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4-Port Ethernet Switch Configuration Notes forthe Cisco 1700 Series Routers

This document describes the configuration of the 4-port 10/100BASE-TX Ethernet switch on Cisco 1711and Cisco 1712 Security Access routers running Cisco IOS Release 12.2(15)ZL and higher, and theCisco WIC-4ESW interface card supported on Cisco 1721, Cisco 1751, Cisco 1751-V, and Cisco 1760routers, running Cisco IOS Release 12.3(2)XC and higher.

The 4-port 10/100BASE-TX Ethernet switch is a Layer 2 Ethernet switch with Layer 3 routingcapability, and supports a maximum of 16 VLANs. (Layer 3 routing is forwarded to the host, and is notactually performed at the switch.)

There are no new or modified commands for use with the switch. All commands used with the switchare documented in the Cisco IOS command reference publications.

The first port on the Cisco WIC-4ESW is always identified as “1.” For the Cisco 1721 router, the portsare referred to as FastEthernet1 to FastEthernet4, no matter in what slot the card is installed.

On the Cisco 1751 router and the Cisco 1760 router, the Fast Ethernet interfaces on Cisco WIC-4ESWare addressed as F<slot>/1 through F<slot>/4, depending in what slot the card is installed. (In thisdocument, the ports will be refered as F1 through F4.)

The following topics provide information about the 4-port Ethernet switch, along with configurationguidelines and examples:

• Benefits, page 2

• Supported Standards, page 2

• Platform Limitations, page 2

• Supported Features, page 3

• Configuration Guidelines, page 16

• Related Documentation, page 41

• Obtaining Documentation, page 41

• Obtaining Technical Assistance, page 42

• Obtaining Additional Publications and Information, page 43

• Glossary, page 44

24-Port Ethernet Switch Configuration Notes for the Cisco 1700 Series Routers

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Benefits

BenefitsThe following benefits are provided by the switch:

• Statistical gains by combining multiple traffic types over a common IP infrastructure

• Security options, including

– IP security (IPSec)

– Intrusion Detection System (IDS) (access control list (ACL))

– Virtual Private Network (VPN)

– Context-based Access Control (CBAC) firewall options

• Broadband WAN options

• The Interface Range Specification feature, which makes configuration easier because

– Identical commands can be entered once for a range of interfaces, rather than being enteredseparately for each interface

– Interface ranges can be saved as macros

Supported StandardsThe following standards are supported:

• 802.1d

• 802.1p

• 802.1q

Platform LimitationsThe following features arenot supported on the switch:

• Virtual Local Area Network (VLAN) trunking protocols (server and client modes, and transparentmode v2)

• Spanning Tree Protocol (STP) backbone fast

• STP portfast Bridge Protocol Data Unit (BPDU) guard

• STP uplink fast

• STP Root Guard

• STP Unidirectional Link Detection (UDLD)

• Port security

• Protected Port

• 802.1x port-based authentication

• Storm control

• Switched Port Analyzer (SPAN)

• Internet Group Management Protocol (IGMP) Snooping


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Supported Features

• 802.1P priority override

• MAC address table commands

• EtherChannel

• Enable or disable per port based on unknown unicast or multicast flooding

• Multicast groups

• IP multicast support

• Cisco Group Management Protocol (CGMP) client, CGMP fast-leave

• Dynamic access ports

• Dynamic trunk protocol

• Dynamic VLANs

• Voice VLANs

• General Attribute Registration Protocol (GARP), GARP Multicast Registration Protocol (GMRP),and GARP VLAN Registration Protocol (GVRP)

• Cisco Inter-Switch Link (ISL) tagging (the chip does not support ISL)

• Layer 3 onboard switching

• Monitoring of VLANs

• Multi-VLAN ports network port

• Shared STP instances

• VLAN-based SPAN

• VLAN Query Protocol (VQP)

• VTP pruning protocol

• Web-based management interface

• Remote Monitoring (RMON)

Supported FeaturesThe switch supports the features described below:

• Layer 2 Ethernet Interfaces, page 4

• Switch Virtual Interfaces (SVIs), page 6

• VLAN Trunking Protocol (Transparent Mode Only), page 6

• Spanning Tree Protocol, page 8

• Cisco Discovery Protocol, page 14

• Quality of Service, page 14


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Supported Features

Layer 2 Ethernet InterfacesThe Ethernet switch supports simultaneous, parallel connections between Layer 2 Ethernet segments.Switched connections between Ethernet segments last only for the duration of the packet. Newconnections can be made between different segments for the next packet.

The Ethernet switch solves congestion problems caused by high-bandwidth devices and a large numberof users by assigning each device (for example, a server) to its own 10-, 100-, or 1000-Mbps segment.Because each Ethernet interface on the switch represents a separate Ethernet segment, servers in aproperly configured switched environment achieve full access to the bandwidth.

Because collisions are a major bottleneck in Ethernet networks, an effective solution is full-duplexcommunication. Normally, Ethernet operates in half-duplex mode, which means that stations can eitherreceive or transmit. In full-duplex mode, two stations can transmit and receive at the same time. Whenpackets can flow in both directions simultaneously, effective Ethernet bandwidth doubles to 20 Mbps for10-Mbps interfaces and to 200 Mbps for Fast Ethernet interfaces.

Switching Frames Between Segments

Each Ethernet interface on an Ethernet switch can connect to a single workstation or server, or to a hubthrough which workstations or servers connect to the network.

On a typical Ethernet hub, all ports connect to a common backplane within the hub, and the bandwidthof the network is shared by all devices attached to the hub. If two stations establish a session that uses asignificant level of bandwidth, the network performance of all other stations attached to the hub isdegraded.

To reduce degradation, the switch treats each interface as an individual segment. When stations ondifferent interfaces need to communicate, the switch forwards frames from one interface to the other atwire speed to ensure that each session receives full bandwidth.

To switch frames between interfaces efficiently, the switch maintains an address table. When a frameenters the switch, it associates the MAC address of the sending station with the interface on which it wasreceived.

Building the Address Table

An Ethernet switch builds the address table by using the source address of the frames received. Whenthe switch receives a frame for a destination address not listed in its address table, it floods the frame toall interfaces of the same VLAN except the interface that received the frame. When the destinationstation replies, the switch adds its relevant source address and interface ID to the address table. Theswitch then forwards subsequent frames to a single interface without flooding to all interfaces. Theaddress table can store at least 1,024 address entries without flooding any entries. The switch uses anaging mechanism, with a fixed aging timer of 5 minutes; if an address remains inactive for 5 minutes, itis removed from the address table.

VLAN Trunks

A trunk is a point-to-point link between one or more Ethernet switch interfaces and another networkingdevice such as a router or a switch. Trunks carry the traffic of multiple VLANs over a single link andallow you to extend VLANs across an entire network. The switch supports only one encapsulation on allEthernet interfaces, 802.1Q-802.1Q, an industry-standard trunking encapsulation.


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Supported Features

Layer 2 Interface Modes

Switchport mode accessputs the interface into nontrunking mode. The interface will stay in access moderegardless of the connected port mode. Only access VLAN traffic will travel on the access port untagged(802.3).

When you connect a Cisco switch to a device other than a Cisco device through an 802.1Q trunk, theCisco switch combines the Spanning Tree instance of the VLAN trunk with the Spanning Tree instanceof the other 802.1Q switch. However, Spanning Tree information for each VLAN is maintained by Ciscoswitches separated by a cloud of 802.1Q switches that are not Cisco switches. The 802.1Q cloudseparating the Cisco switches and that is not Cisco devised, is treated as a single trunk link between theswitches.

Make sure that the native VLAN for an 802.1Q trunk is the same on both ends of the trunk link. If theVLAN on one end of the trunk is different from the VLAN on the other end, Spanning Tree loops mightresult. Inconsistencies detected by a Cisco switch mark the line as broken and block traffic for thespecific VLAN.

Caution Disabling Spanning Tree protocol on the VLAN of an 802.1Q trunk without disabling Spanning Treeprotocol on every VLAN in the network can potentially cause Spanning Tree loops. Cisco recommendsthat you leave Spanning Tree protocol enabled on the VLAN of an 802.1Q trunk or that you disableSpanning Tree protocol on every VLAN in the network. Make sure that your network is loop-free beforedisabling Spanning Tree protocol.

Layer 2 Interface Configuration Guidelines and Restrictions

Follow these guidelines and restrictions when configuring Layer 2 interfaces:

In a network of Cisco switches connected through 802.1Q trunks, the switches maintain one instance ofSpanning Tree for each VLAN allowed on the trunks. 802.1Q switches that are not Cisco switches,maintain only one instance of Spanning Tree for all VLANs allowed on the trunks.

Table 1 Default Layer 2 Ethernet Interface Configuration

Feature Default Value

Interface mode switchport mode access

Trunk encapsulation switchport trunk encapsulation dot1q

Allowed VLAN range VLANs 1-1005

Default VLAN (for access ports) VLAN 1

Native VLAN (for 802.1Q trunks) VLAN 1

Spanning Tree Protocol (STP) Enabled for all VLANs

STP port priority 128

STP port cost 100 for 10-Mbps Ethernet interfaces

19 for 10/100-Mbps Fast Ethernet interfaces

19 for 1000-Mbps Fast Ethernet interfaces


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Supported Features

Switch Virtual Interfaces (SVIs)A switch virtual interface (SVI) represents a VLAN of switch ports as one interface to the routing orbridging function in the system. Only one SVI can be associated with a VLAN, but it is necessary toconfigure an SVI for a VLAN only when you wish to route between VLANs, fallback-bridgenonroutable protocols between VLANs, or to provide IP host connectivity to the switch. By default, anSVI is created for the default VLAN (VLAN 1) to permit remote switch administration. Additional SVIsmust be explicitly configured. In Layer 2 mode, SVIs provide IP host connectivity only to the system;in Layer 3 mode, you can configure routing across SVIs.

SVIs are created the first time that you enter thevlan interface configuration command for a VLANinterface. The VLAN corresponds to the VLAN tag associated with data frames on an Inter-Switch Link(ISL) or 802.1Q encapsulated trunk or the VLAN ID configured for an access port. Configure a VLANinterface for each VLAN for which you want to route traffic, and assign it an IP address.

SVIs support routing protocol and bridging configurations.

Note You must use thevlan databasecommand to completely configure VLAN interface instances. Thevlan databasecommand adds the VLAN instance to the Flash-based database. You must also enter theinterface vlan command to enable the VLAN interface. For additional information, see theconfiguration guidelines and examples in the“Configuring VLANs and SVIs” section on page 22.

VLAN Trunking Protocol (Transparent Mode Only)VTP is a Layer 2 messaging protocol that maintains VLAN configuration consistency by managing theaddition, deletion, and renaming of VLANs within a VTP domain. A VTP domain (also called aVLANmanagement domain) is made up of one or more switches that share the same VTP domain name andthat are interconnected with trunks.

VTP minimizes misconfigurations and configuration inconsistencies that can result in a number ofproblems, such as duplicate VLAN names, incorrect VLAN-type specifications, and security violations.Before you create VLANs, you must decide whether to use VTP in your network. With VTP, you canmake configuration changes centrally on one or more switches and have those changes automaticallycommunicated to all the other switches in the network.

The following sections provide information about VTP.

VTP Domain

A VTP domain (or VLAN management domain) is made up of one or more interconnected switches thatshare the same VTP domain name. A switch can be configured to be in one and only one VTP domain.You make global VLAN configuration changes for the domain using either the command-line interface(CLI) or Simple Network Management Protocol (SNMP).

By default, the switch is in VTP server mode and is in an unnamed domain state until the switch receivesan advertisement for a domain over a trunk link or until you configure a management domain. You cannotcreate or modify VLANs on a VTP server until the management domain name is specified or learned.

If the switch receives a VTP advertisement over a trunk link, it inherits the management domain nameand the VTP configuration revision number. The switch ignores advertisements with a differentmanagement domain name or an earlier configuration revision number.


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Supported Features

When you make a change to the VLAN configuration on a VTP server, the change is propagated to allswitches in the VTP domain. VTP advertisements are transmitted out all trunk connections using IEEE802.1Q encapsulation.

VTP maps VLANs dynamically across multiple LAN types with unique names and internal indexassociations. Mapping eliminates excessive device administration required from network administrators.

Supported VTP Mode

The switch supports VTP only in transparent mode. By configuring the switch as VTP transparent, youcan create and modify VLANs, but the changes affect only the individual switch.

A VTP transparent switch does not advertise its VLAN configuration and does not synchronize itsVLAN configuration based on received advertisements. However, in VTP version 2, transparent switchesdo forward VTP advertisements that they receive out their trunk interfaces.

VTP Advertisements

Each switch in the VTP domain sends periodic advertisements out each trunk interface to a reservedmulticast address. VTP advertisements are received by neighboring switches, which update their VTPand VLAN configurations as necessary.

The following global configuration information is distributed in VTP advertisements:

• VLAN IDs (801.Q)

• VTP domain name

• VTP configuration revision number

• VLAN configuration, including maximum transmission unit (MTU) size for each VLAN

• Frame format

VTP Configuration Guidelines and Restrictions

Follow these guidelines and restrictions when implementing VTP in your network:

• All switches in a VTP domain must run the same VTP version.

• You must configure a password on each switch in the management domain when in secure mode.

• A VTP version 2–capable switch can operate in the same VTP domain as a switch running VTPversion 1, provided that VTP version 2 is disabled on the VTP version 2–capable switch. (VTPversion 2 is disabled by default.)

• Do not enable VTP version 2 on a switch unless all switches in the same VTP domain are version2-capable. When you enable VTP version 2 on a switch, all version 2–capable switches in thedomain enable VTP version 2

• The Cisco IOSend andCtrl -Z commands are not supported in VLAN database mode.

• The VLAN database stored on internal Flash memory is supported.

• Use thesqueeze flashcommand to remove old copies of overwritten VLAN databases.


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Supported Features

Spanning Tree ProtocolThis section provides information about configuring the STP on an Ethernet switch.

Spanning Tree is a Layer 2 link management protocol that provides path redundancy while preventingundesirable loops in the network. For a Layer 2 Ethernet network to function properly, only one activepath can exist between any two stations. Spanning Tree operation is transparent to end stations, whichcannot detect whether they are connected to a single LAN segment or to a switched LAN of multiplesegments.

The Ethernet switch uses STP (the IEEE 802.1D bridge protocol) on all VLANs. By default, a singleinstance of STP runs on each configured VLAN (provided that you do not manually disable STP). Youcan enable and disable STP on a per-VLAN basis.

When you create fault-tolerant internetworks, you must have a loop-free path between all nodes in anetwork. The Spanning Tree algorithm calculates the best loop-free path throughout a switched Layer 2network. Switches send and receive Spanning Tree frames at regular intervals. The switches do notforward these frames, but use the frames to construct a loop-free path.

Multiple active paths between end stations cause loops in the network. If a loop exists in the network,end stations might receive duplicate messages and switches might learn endstation MAC addresses onmultiple Layer 2 interfaces. These conditions result in an unstable network.

STP defines a tree with a root switch and a loop-free path from the root to all switches in the Layer 2network. Spanning Tree forces redundant data paths into a standby (blocked) state. If a network segmentin the Spanning Tree fails and a redundant path exists, the Spanning Tree algorithm recalculates theSpanning Tree topology and activates the standby path.

When two ports on a switch are part of a loop, the Spanning Tree port priority and port path cost settingdetermine which port is put in the forwarding state and which port is put in the blocking state. TheSpanning Tree port priority value represents the location of an interface in the network topology and howwell located it is to pass traffic. The Spanning Tree port path cost value represents media speed.

Bridge Protocol Data Units

The stable active Spanning Tree topology of a switched network is determined by the following:

• The unique bridge ID (bridge priority and MAC address) associated with each VLAN on each switch

• The Spanning Tree path cost to the root bridge

• The port identifier (port priority and MAC address) associated with each Layer 2 interface

The bridge protocol data units (BPDUs) are transmitted in one direction from the root switch, and eachswitch sends configuration BPDUs to communicate and compute the Spanning Tree topology. Eachconfiguration BPDU contains the following minimal information:

• The unique bridge ID of the switch that the transmitting switch believes to be the root switch

• The Spanning Tree path cost to the root

• The bridge ID of the transmitting bridge

• Message age

• The identifier of the transmitting port

• Values for the hello, forward delay, and max-age protocol timers


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Supported Features

Note When a switch transmits a bridge packet data unit (BPDU) frame, all switches connected to the LAN onwhich the frame is transmitted receive the BPDU. When a switch receives a BPDU, it does not forwardthe frame but instead uses the information in the frame to calculate a BPDU, and, if the topologychanges, initiate a BPDU transmission.

A BPDU exchange results in the following:

• One switch is elected as the root switch.

• The shortest distance to the root switch is calculated for each switch based on the path cost.

• A designated bridge for each LAN segment is selected. This is the switch closest to the root bridgethrough which frames is forwarded to the root.

• A root port is selected. This is the port providing the best path from the bridge to the root bridge.

• Ports included in the Spanning Tree are selected.

• Election of the root bridge.

For each VLAN, the switch with the highest bridge priority (the lowest numerical priority value) iselected as the root switch. If all switches are configured with the default priority (32768), the switch withthe lowest MAC address in the VLAN becomes the root switch.

The Spanning Tree root switch is the logical center of the Spanning Tree topology in a switched network.All paths that are not needed to reach the root switch from anywhere in the switched network are placedin Spanning Tree blocking mode.

BPDUs contain information about the transmitting bridge and its ports, including bridge and MACaddresses, bridge priority, port priority, and path cost. Spanning Tree uses this information to elect theroot bridge and root port for the switched network, as well as the root port and designated port for eachswitched segment.

STP Timers

Table 2 describes the STP timers that affect the entire Spanning Tree performance.

Table 2 STP Timers

Timer Purpose

Hello timer Determines how often the switch broadcasts hello messages to other switches.

Forward delay timer Determines how long each of the listening and learning states will last beforethe port begins forwarding

Maximum age timer Determines the amount of time that protocol information received on a port isstored by the switch.


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Supported Features

Spanning Tree Port States

Propagation delays can occur when protocol information passes through a switched LAN. As a result,topology changes can take place at different times and at different places in a switched network. Whena Layer 2 interface transitions directly from nonparticipation in the Spanning Tree topology to theforwarding state, it can create temporary data loops.

Ports must wait for new topology information to propagate through the switched LAN before starting toforward frames. They must allow the frame lifetime to expire for frames that have been forwarded usingthe old topology.

Each Layer 2 interface on a switch using Spanning Tree exists in one of the following five states:

• Blocking—The Layer 2 interface does not participate in frame forwarding.

• Listening—First transitional state after the blocking state when Spanning Tree determines that theLayer 2 interface should participate in frame forwarding.

• Learning—The Layer 2 interface prepares to participate in frame forwarding.

• Forwarding—The Layer 2 interface forwards frames.

• Disabled—The Layer 2 interface does not participate in Spanning Tree and is not forwardingframes.

A Layer 2 interface moves through these five states as follows:

• From initialization to blocking

• From blocking to listening or to disabled

• From listening to learning or to disabled

• From learning to forwarding or to disabled

• From forwarding to disabled

Note For an illustration of how a port moves through the five stages mentioned above, refer to Figure 1 (STPPort States) in the16- and 36-Port Ethernet Switch Module for Cisco 2600 Series, Cisco 3600 Series, andCisco 3700 Series documentation that is available at the following URL:http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122newft/122t/122t11/ft1636nm.htm#1433396.

This document includes illustrations and detailed information about switch functionality.

When you enable Spanning Tree, every port in the switch, VLAN, or network goes through the blockingstate and the transitory states of listening and learning at power up. If properly configured, each Layer 2interface stabilizes to the forwarding or blocking state.

When the Spanning Tree algorithm places a Layer 2 interface in the forwarding state, the followingprocess occurs:

1. The Layer 2 interface is put into the listening state while it waits for protocol information thatsuggests that it should go to the blocking state.

2. The Layer 2 interface waits for the forward delay timer to expire, moves the Layer 2 interface to thelearning state, and resets the forward delay timer.

http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122newft/122t/122t11/ft1636nm.htm#18897

http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122newft/122t/122t11/ft1636nm.htm#18897

http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122newft/122t/122t11/ft1636nm.htm

http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122newft/122t/122t11/ft1636nm.htm


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Supported Features

3. In the learning state, the Layer 2 interface continues to block frame forwarding as it learns endstation location information for the forwarding database.

4. The Layer 2 interface waits for the forward delay timer to expire and then moves the Layer 2interface to the forwarding state, where both learning and frame forwarding are enabled.

Blocking State

A Layer 2 interface in the blocking state does not participate in frame forwarding. After initialization, aBPDU is sent out to each Layer 2 interface in the switch. A switch initially assumes it is the root untilit exchanges BPDUs with other switches. This exchange establishes which switch in the network is theroot or root bridge. If only one switch is in the network, no exchange occurs, the forward delay timerexpires, and the ports move to the listening state. A port always enters the blocking state followingswitch initialization.

A Layer 2 interface in the blocking state performs as follows:

• Discards frames received from the attached segment.

• Discards frames switched from another interface for forwarding.

• Does not incorporate end station location into its address database. (There is no learning on ablocking Layer 2 interface, so there is no address database update.)

• Receives BPDUs and directs them to the system module.

• Does not transmit BPDUs received from the system module.

• Receives and responds to network management messages.

Listening State

The listening state is the first transitional state a Layer 2 interface enters after the blocking state. TheLayer 2 interface enters this state when STP determines that the Layer 2 interface should participate inframe forwarding.

A Layer 2 interface in the listening state performs as follows:



• Does not incorporate end station location into its address database. (There is no learning at thispoint, so there is no address database update.)


• Receives, processes, and transmits BPDUs received from the system module.



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Supported Features

Learning State

A Layer 2 interface in the learning state prepares to participate in frame forwarding. The Layer 2interface enters the learning state from the listening state.

A Layer 2 interface in the learning state performs as follows:



• Incorporates end station location into its address database.


• Receives, processes, and transmits BPDUs received from the system module.


Forwarding State

A Layer 2 interface in the forwarding state forwards frames. The Layer 2 interface enters the forwardingstate from the learning state.

A Layer 2 interface in the forwarding state performs as follows:

• Forwards frames received from the attached segment.

• Forwards frames switched from another Layer 2 interface for forwarding.

• Incorporates end station location information into its address database.


• Processes BPDUs received from the system module.


Disabled State

A Layer 2 interface in the disabled state does not participate in frame forwarding or Spanning Tree. ALayer 2 interface in the disabled state is virtually nonoperational.

A disabled Layer 2 interface performs as follows:


• Discards frames switched from another Layer 2 interface for forwarding.

• Does not incorporate end station location into its address database. (There is no learning, so there isno address database update.)

• Does not receive BPDUs.

• Does not receive BPDUs for transmission from the system module.


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Supported Features

Default Spanning Tree Configuration

Table 3 provides a description of the default Spanning Tree configuration.

Spanning Tree Port Priority

In the event of a loop, Spanning Tree considers port priority when selecting an interface to put into theforwarding state. You can assign higher priority values to interfaces that you want Spanning Tree toselect first, and lower priority values to interfaces that you want Spanning Tree to select last. If allinterfaces have the same priority value, Spanning Tree puts the interface with the lowest interfacenumber in the forwarding state and blocks other interfaces. The possible priority range is 0 through 255,configurable in increments of 4 (the default is 128).

Cisco IOS software uses the port priority value when the interface is configured as an access port anduses VLAN port priority values when the interface is configured as a trunk port.

Spanning Tree Port Cost

The Spanning Tree port path cost default value is derived from the media speed of an interface. In theevent of a loop, Spanning Tree considers port cost when selecting an interface to put into the forwardingstate. You can assign lower cost values to interfaces that you want Spanning Tree to select first and highercost values to interfaces that you want Spanning Tree to select last. If all interfaces have the same costvalue, Spanning Tree puts the interface with the lowest interface number in the forwarding state andblocks other interfaces.

The possible cost range is 0 through 65535 (the default is media-specific).

Spanning Tree uses the port cost value when the interface is configured as an access port and uses VLANport cost values when the interface is configured as a trunk port.

Table 3 Spanning Tree Default Configuration

Feature Default Value

Enable state Spanning Tree enabled for all VLANs

Bridge priority 32768

Spanning Tree port priority (configurable on aper-interface basis)

128

Spanning Tree port cost (configurable on a per-interfacebasis)

Fast Ethernet: 19Ethernet: 100

Spanning Tree VLAN port priority (configurable on aper-VLAN basis)

128

Spanning Tree VLAN port cost (configurable on aper-VLAN basis)

Fast Ethernet: 10

Ethernet: 10

Hello time 2 seconds

Forward delay time 15 seconds

Maximum aging time 20 seconds


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Supported Features

Cisco Discovery ProtocolCisco Discovery Protocol (CDP) is a protocol that runs over Layer 2 (the data link layer) on all Ciscorouters, bridges, access servers, and switches. CDP allows network management applications to discoverCisco devices that are neighbors of already known devices, in particular, neighbors running lower-layer,transparent protocols. With CDP, network management applications can learn the device type and theSNMP agent address of neighboring devices. This feature enables applications to send SNMP queries toneighboring devices.

CDP runs on all LAN and WAN media that support Subnetwork Access Protocol (SNAP). EachCDP-configured device sends periodic messages to a multicast address. Each device advertises at leastone address at which it can receive SNMP messages. The advertisements also contain the time-to-live,or hold-time information, which indicates the length of time a receiving device should hold CDPinformation before discarding it.

Quality of ServiceTypically, networks operate on a best-effort delivery basis, which means that all traffic has equal priorityand an equal chance of being delivered in a timely manner. When congestion occurs, all traffic has anequal chance of being dropped.

With the QoS feature configured on your switch, you can select specific network traffic, prioritize itaccording to its relative importance, and use congestion-management and congestion-avoidancetechniques to provide preferential treatment. Implementing QoS in your network makes networkperformance more predictable and bandwidth utilization more effective.

The QoS implementation for this release is based on the DiffServ architecture, an emerging standardfrom the Internet Engineering Task Force (IETF). This architecture specifies that each packet isclassified upon entry into the network. The classification is carried in the IP packet header, using 6 bitsfrom the deprecated IP type of service (ToS) field to carry the classification (class) information.Classification can also be carried in the Layer 2 frame.

These special bits in the Layer 2 frame or a Layer 3 packet are described here and shown inFigure 1 onpage 15.

• Prioritization values in Layer 2 frames:

• Layer 2 802.1Q frame headers have a 2-byte Tag Control Information field that carries the CoSvalue in the three most-significant bits, which are called theUser Priority bits. On interfacesconfigured as Layer 2 802.1Q trunks, all traffic is in 802.1Q frames except for traffic in thenative VLAN.

• Other frame types cannot carry Layer 2 CoS values.

• Layer 2 CoS values range from 0 for low priority to 7 for high priority.

• Prioritization bits in Layer 3 packets:

• Layer 3 IP packets can carry either an IP precedence value or a Differentiated Services CodePoint (DSCP) value. QoS supports the use of either value, because DSCP values arebackward-compatible with IP precedence values.

• IP precedence values range from 0 to 7.

• DSCP values range from 0 to 63.


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Supported Features

Figure 1 QoS Classification Layers in Frames and Packets

Note Layer 2 Inter-Switch Link (ISL) frame is not supported in this release.

Note Layer 3 IPv6 packets are dropped when received by the switch.

All switches and routers across the Internet rely on the class information to provide the same forwardingtreatment to packets with the same class information and different treatment to packets with differentclass information. The class information in the packet can be assigned by end hosts or by switches orrouters along the way, based on a configured policy, detailed examination of the packet, or both. Detailedexamination of the packet is expected to happen closer to the edge of the network so that the coreswitches and routers are not overloaded.

Switches and routers along the path can use the class information to limit the amount of resourcesallocated per traffic class. The behavior of an individual device when handling traffic in the DiffServarchitecture is called per-hop behavior. If all devices along a path provide a consistent per-hop behavior,you can construct an end-to-end QoS solution.

Implementing QoS in your network can be a simple or complex task and depends on the QoS featuresoffered by your internetworking devices, the traffic types and patterns in your network, and thegranularity of control you need over incoming and outgoing traffic.

The Ethernet switch can function as a Layer 2 switch connected to a Layer 3 router. When a packet entersthe Layer 2 engine directly from a switch port, it is placed into one of four queues in the dynamic,120 KB shared memory buffer. The queue assignment is based on the dot1p value in the packet. Thequeues are then serviced on a weighted round-robin (WRR) basis.

4697

4

Encapsulated Packet

Layer 2header

IP header

3 bits used for CoS

Data

Layer 2 ISL Frame

ISL header(26 bytes)

Encapsulated frame 1...(24.5 KB)

FCS(4 bytes)

Layer 2 802.1Q and 802.1p Frame

Preamble Start framedelimiter

DA

Len

SA Tag PT Data FCS

Layer 3 IPv4 Packet

Versionlength

ToS(1 byte)

ID Offset TTL Proto FCS IP-SA IP-DA Data

3 bits used for CoS (user priority)

IP precedence or DSCP


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Configuration Guidelines

Table 4 summarizes the queues, CoS values, and weights for Layer 2 QoS on the Ethernet switch.

The weights specify the number of packets that are serviced in the queue before moving on to the nextqueue. If the queue has no packets to be serviced, it is skipped. Weighted Random Early Detection(WRED) is not supported on the Fast Ethernet ports.

The WRR default values cannot be changed. There are currently no CLI commands to determine QoSinformation for WRR weights and queue mappings. You cannot configure port based QoS on the Layer2 switch ports.

Configuration GuidelinesThis section provides guidelines for configuring the switch and contains the following sections.

• Configuration Prerequisites, page 16

• Configuring Layer 2 Interfaces, page 17

• Configuring VLANs and SVIs, page 22

• Configuring VTP (Transparent Mode), page 26

• Configuring Spanning Tree, page 27

• Verifying the Switch Port Configuration, page 34

• Configuring IP Information, page 34

• Configuration Examples, page 36

• Optional Interface Feature Examples, page 37

• VLAN Configuration Example, page 38

• Disabling VTP (VTP Transparent Mode) Example, page 38

• Spanning Tree Examples, page 38

Configuration PrerequisitesThe following are prerequisites to configuring the Ethernet switch:

• Configure IP routing. (Refer to theCisco IOS IP Configuration Guide.)

• Use of the Cisco IOS T Release, beginning with 12.2(15)ZL or later for Cisco WIC-4ESW support.(Refer to the Cisco IOS documentation.)

Table 4 Queues, CoS Values, and Weights for Layer2 QoS

Queue Number CoS Value Weight

3 6,7 8

2 4,5 4

1 0,3 2

0 1,2 1

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Configuring Layer 2 InterfacesThis section provides the following configuraiton information:

• Configuring a Range of Interfaces, page 17 (required)

• Defining a Range Macro, page 17 (optional)

• Configuring Layer 2 Optional Interface Features, page 18 (optional)

Configuring a Range of Interfaces

Use theinterface rangecommand in global configuration mode to configure a range of interfaces.

Defining a Range Macro

Use the define interface-range command in global configuration mode to define an interface rangemacro:

Command PurposeRouter(config)# interface range { macromacro_name | FastEthernet interface [ -interface ] | vlan vlan_ID} [ , FastEthernetinterface [ - interface ] | vlan vlan_ID ]

Select the range of interfaces to be configured.

• The space before the dash is required. Forexample, the commandinterface rangefastethernet 1 - 4 for a Cisco 1721 router isvalid; the commandinterface rangefastethernet 1-4 is not valid. The commandinterface range fastethernet<slot>/1 -<slot>/4 for Cisco 1751 and Cisco 1760 routersis valid; the commandinterface rangefastethernet<slot>/1-<slot>/4 is not valid.

• You can enter one macro or up to fivecomma-separated ranges.

• Comma-separated ranges can include bothVLANs and physical interfaces.

• You are not required to enter spaces before orafter the comma.

• The interface range command only supportsVLAN interfaces that are configured with theinterface vlan command.

Command PurposeRouter(config)# define interface-rangemacro_name { FastEthernet interface [ -interface ] | { vlan vlan_ID - vlan_ID } | [ ,FastEthernet interface [ - interface ]

Define the interface-range macro and save it inNVRAM.

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Verifying Configuration of a Range of Interfaces

Use theshow running-configuration command to show the defined interface-range macroconfiguration, as shown below:

Router# show running-configuration | include define interface-range enet_listdefine interface-range enet_list FastEthernet1 - 4

Configuring Layer 2 Optional Interface Features

• Interface Speed and Duplex Configuration Guidelines, page 18

• Configuring the Interface Speed, page 18

• Configuring the Interface Duplex Mode, page 19

• Configuring a Description for an Interface, page 20

• Configuring an Ethernet Interface as a Layer 2 Trunk, page 20

• Configuring an Ethernet Interface as Layer 2 Access, page 21

Interface Speed and Duplex Configuration Guidelines

When configuring an interface speed and duplex mode, note these guidelines:

• If both ends of the line support autonegotiation, Cisco highly recommends the defaultautonegotiation settings.

• If one interface supports autonegotiation and the other end does not, configure duplex and speed onboth interfaces; do not use theauto setting on the supported side.

• Both ends of the line need to be configured to the same setting. For example, both hard-set or bothauto-negotiate. Mismatched settings are not supported.

Caution Changing the interface speed and duplex mode configuration might shut down and reenable the interfaceduring the reconfiguration.

Configuring the Interface Speed

Follow these steps to set the interface speed, beginning with theinterface fastethernet command inglobal configuration mode:

Note If you set the interface speed to auto on a 10/100-Mbps Ethernet interface, both speed and duplex areautonegotiated.

Command Purpose

Step 1 Router(config)# interface fastethernetinterface

Selects the interface to be configured.

Step 2 Router(config-if)# speed [ 10 | 100 | auto ] Sets the interface speed of the interface.


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Configuring the Interface Duplex Mode

Follow these steps to set the duplex mode of an Ethernet or Fast Ethernet interface, beginning with theinterface fastethernet command in global configuration mode:

Note If you set the port speed to auto on a 10/100-Mbps Ethernet interface, both speed and duplex areautonegotiated. You cannot change the duplex mode of autonegotiation interfaces.

The following example shows how to set the interface duplex mode to full on Fast Ethernet interface 4:

Router(config)# interface fastethernet 4Router(config-if)# duplex full

Verifying Interface Speed and Duplex Mode Configuration

Use theshow interfacescommand to verify the interface speed and duplex mode configuration for aninterface, as shown in the following output example:

Router# show interfaces fastethernet 4

FastEthernet4 is up, line protocol is downHardware is Fast Ethernet, address is 0000.0000.0c89 (bia 0000.0000.0c89)MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec, reliability 255/255, txload 1/255, rxload 1/255

Encapsulation ARPA, loopback not setKeepalive set (10 sec)Auto-duplex, Auto-speedARP type: ARPA, ARP Timeout 04:00:00Last input never, output never, output hang neverLast clearing of "show interface" counters neverQueueing strategy: fifoOutput queue 0/40, 0 drops; input queue 0/75, 0 drops5 minute input rate 0 bits/sec, 0 packets/sec5 minute output rate 0 bits/sec, 0 packets/sec 0 packets input, 0 bytes, 0 no buffer Received 0 broadcasts, 0 runts, 0 giants, 0 throttles 0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored 0 input packets with dribble condition detected 3 packets output, 1074 bytes, 0 underruns(0/0/0) 0 output errors, 0 collisions, 5 interface resets 0 babbles, 0 late collision, 0 deferred 0 lost carrier, 0 no carrier 0 output buffer failures, 0 output buffers swapped out

Router#

Command Purpose

Step 1 Router(config)# interface fastethernetinterface

Selects the interface to be configured.

Step 2 Router(config-if)# duplex [auto | full |half]

Sets the duplex mode of the interface.


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Configuring a Description for an Interface

You can add a description of an interface to help you remember its function. The description appears inthe output of the following commands: show configuration, show running-config, andshowinterfaces.

Use thedescription command, in interface configuration mode, to add a description for an interface:

Configuring an Ethernet Interface as a Layer 2 Trunk

Use the following commands, beginning in global configuration mode, to configure an Ethernet interfaceas a Layer 2 trunk:

Note Ports do not support Dynamic Trunking Protocol (DTP). Ensure that the neighboring switch is set to amode that will not send DTP.

Verifying an Ethernet Interface as a Layer 2 Trunk

Use the followingshow commands to verify the configuration for an Ethernet interface as a Layer 2trunk.

Router# show running - config interface fastethernet 4

Building configuration...Current configuration:!interface FastEthernet4no ip addressswitchport trunk encapsulation dot1qend

Router# show interfaces fastethernet 4 switchport

Command PurposeRouter(config-if)# description string Adds a description for an interface.

Command Purpose

Step 1 Router(config)# interface fastethernet port Selects the interface to configure.

Step 2 Router(config-if)# shutdown (Optional) Shuts down the interface to prevent trafficflow until configuration is complete.

Note Encapsulation is always dot1q.

Step 3 Router(config-if)# switch port mode trunk Configures the interface as a Layer 2 trunk.

Step 4 Router(config-if)# switch port trunknative vlan vlan _num

For 802.1Q trunks, specifies the native VLAN.

Step 5 Router(config-if)# switch port trunkallowed vlan { add | except | none |remove } vlan1 [, vlan [, vlan [, ... ]]

(Optional) Configures the list of VLANs allowed onthe trunk. All VLANs are allowed by default. Youcannot remove any of the default VLANs from a trunk.

Step 6 Router(config-if)# no shutdown Activates the interface. (Required only if you shutdown the interface.)

Step 7 Router(config-if)# end Exits configuration mode.


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Name: Fa4Switchport: EnabledAdministrative Mode: trunkOperational Mode: trunkAdministrative Trunking Encapsulation: dot1qNegotiation of Trunking: DisabledAccess Mode VLAN: 0 ((Inactive))Trunking Native Mode VLAN: 1 (default)Trunking VLANs Enabled: ALLTrunking VLANs Active: nonePriority for untagged frames: 0Override vlan tag priority: FALSEVoice VLAN: noneAppliance trust: none

Router# show interfaces fastethernet 4 trunkPort Mode Encapsulation Status Native vlanFa4 on 802.1q trunking 1

Port Vlans allowed on trunkFa4 1-1005

Port Vlans allowed and active in management domainFa4 1-2,200,300

Port Vlans in spanning tree forwarding state and not prunedFa4 1-2,200,300Router#

Configuring an Ethernet Interface as Layer 2 Access

Use the following commands, beginning in global configuration mode, to configure an Ethernet interfaceas Layer 2 access:

Verifying an Ethernet Interface as Layer 2 Access

Use theshow running-config interface command to verify therunningconfiguration of the interface,as shown below:

Router# show running-config interface fastethernet port

Use theshow interfacescommand to verify the switch port configuration of the interface, as shownbelow:

Router# show interfaces fastethernet port switchport

Command Purpose

Step 1 Router(config)# interface fastethernet port Selects the interface to configure.

Step 2 Router(config-if)# shutdown (Optional) Shuts down the interface to preventtraffic flow until configuration is complete.

Encapsulation is always dot1q.

Step 3 Router(config-if)# switchport mode access Configures the interface as a Layer 2 access.

Step 4 Router(config-if)# switchport access vlanvlan _num

For access ports, specifies the access vlan.

Step 5 Router(config-if)# no shutdown Activates the interface. (Required only if you shutdown the interface.)



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Configuring VLANs and SVIsThis section describes how to configure VLANs and SVIs on the switch, and contains the followingsections:

• Configuring VLANs, page 22

• Configuring SVIs, page 23

• Deleting a VLAN Instance from the Database, page 24

• Deleting an SVI, page 26

Configuring VLANs

Use the following commands, beginning in privileged EXEC mode, to configure an Ethernet interfaceas Layer 2 access:

Verifying the VLAN Configuration

You can verify the VLAN configuration in VLAN database mode.

Use theshow command in VLAN database mode to verify the VLAN configuration, as shown below:

Router(vlan)# show VLAN ISL Id: 1 Name: default Media Type: Ethernet VLAN 802.10 Id: 100001 State: Operational MTU: 1500 Translational Bridged VLAN: 1002 Translational Bridged VLAN: 1003

VLAN ISL Id: 2 Name: VLAN0002 Media Type: Ethernet VLAN 802.10 Id: 100002 State: Operational MTU: 1500

VLAN ISL Id: 1002 Name: fddi-default Media Type: FDDI VLAN 802.10 Id: 101002 State: Operational MTU: 1500 Bridge Type: SRB Translational Bridged VLAN: 1 Translational Bridged VLAN: 1003

Command Purpose

Step 1 Router# vlan database Enters VLAN configuration mode.

Step 2 Router(vlan)# vlan vlan _id Adds an Ethernet VLAN.

Step 3 Router(vlan)# exit Updates the VLAN database, propagates it throughoutthe administrative domain, and returns to privilegedEXEC mode.


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<snip>

Router(vlan)#

Enter theshow vlan-switchcommand in EXEC mode using the Cisco IOS CLI to verify the VLANconfiguration, as shown below:

Router# show vlan-switch

VLAN Name Status Ports---- -------------------------------- --------- -------------------------------1 default active Fa1, Fa22 VLAN0002 active Fa3200 VLAN0200 active300 VLAN0300 active1002 fddi-default active1003 token-ring-default active1004 fddinet-default active1005 trnet-default active

VLAN Type SAID MTU Parent RingNo BridgeNo Stp BrdgMode Trans1 Trans2---- ----- ---------- ----- ------ ------ -------- ---- -------- ------ ------1 enet 100001 1500 - - - - - 1002 10031002 fddi 101002 1500 - - - - - 1 10031003 tr 101003 1500 1005 0 - - srb 1 10021004 fdnet 101004 1500 - - 1 ibm - 0 01005 trnet 101005 1500 - - 1 ibm - 0 0Router#

Configuring SVIs

Use the following commands, beginning in global configuration mode, to configure an SVI for Layer 3processing:

Note One or more switch interfaces must be configured to belong to the VLAN for the SVI to be operational.See the“Configuring an Ethernet Interface as a Layer 2 Trunk” section on page 20and the“Configuringan Ethernet Interface as Layer 2 Access” section on page 21 for information about how to add one ormore ports to a VLAN.

Command Purpose

Step 1 Router(config)# interface Vlan vlan _num Adds an SVI interface for the specified VLAN.

Step 2 Router(config-if)# ip address ip_addresssubnet_mask

(Optional) Adds an IP address for Layer 3 routingcapability.



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Verifying the SVI Configuration

Use theshow interface vlanvlan _id command to verify the SVI configuration, as shown in thefollowing output example:

Router# show interface vlan 2Vlan2 is up, line protocol is up Hardware is EtherSVI, address is 0005.9a39.4f70 (bia 0005.9a39.4f70) MTU 1500 bytes, BW 100000 Kbit, DLY 1000000 usec, reliability 255/255, txload 1/255, rxload 1/255 Encapsulation ARPA, loopback not set ARP type: ARPA, ARP Timeout 04:00:00 Last input never, output never, output hang never Last clearing of "show interface" counters never Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0 Queueing strategy: fifo Output queue: 0/40 (size/max) 5 minute input rate 0 bits/sec, 0 packets/sec 5 minute output rate 0 bits/sec, 0 packets/sec 0 packets input, 0 bytes, 0 no buffer Received 0 broadcasts, 0 runts, 0 giants, 0 throttles 0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored 0 packets output, 0 bytes, 0 underruns 0 output errors, 3 interface resets 0 output buffer failures, 0 output buffers swapped outRouter#

Deleting a VLAN Instance from the Database

When you delete a VLAN from a switch that is in VTP server mode, the VLAN is removed from allswitches in the VTP domain. When you delete a VLAN from a switch that is in VTP transparent mode,the VLAN is deleted only on that specific switch.

You cannot delete the default VLANs for the different media types: Ethernet VLAN 1 and FDDI orToken Ring VLANs 1002 to 1005.

Use the following commands, beginning in privileged EXEC mode, to delete a VLAN from the database:

Command Purpose


Step 2 Router(vlan)# no vlan vlan _id Deletes the VLAN.

Step 3 Router(vlan)# exit Updates the VLAN database, propagates itthroughout the administrative domain, and returnsto privileged EXEC mode.


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Verifying VLAN Deletion

You can verify that a VLAN has been deleted from the switch in VLAN database mode.

Use theshowcommand in VLAN database mode to verify that a VLAN has been deleted from theswitch, as shown in the following output example:

Router(vlan)# show VLAN ISL Id: 1 Name: default Media Type: Ethernet VLAN 802.10 Id: 100001 State: Operational MTU: 1500 Translational Bridged VLAN: 1002 Translational Bridged VLAN: 1003

VLAN ISL Id: 1002 Name: fddi-default Media Type: FDDI VLAN 802.10 Id: 101002 State: Operational MTU: 1500 Bridge Type: SRB Translational Bridged VLAN: 1 Translational Bridged VLAN: 1003<snip>

Router(vlan)#

Enter theshow vlan-switch briefcommand in EXEC mode, using the Cisco IOS CLI to verify that aVLAN has been deleted from the switch, as shown in the following output example:

Router# show vlan - switch brief

VLAN Name Status Ports---- -------------------------------- --------- -------------------------------1 default active Fa1, Fa22 VLAN0002 active Fa3200 VLAN0200 active300 VLAN0300 active1002 fddi-default active1003 token-ring-default active1004 fddinet-default active1005 trnet-default activeRouter#


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Deleting an SVI

Use the following commands, beginning in global configuration mode, to delete an SVI:

Note Deleting an SVI does not delete the VLAN.

Configuring VTP (Transparent Mode)The Ethernet switch supports VTP only in transparent mode. This section describes how to configure theEthernet switch in VTP transparent mode. When you configure the switch as VTP transparent, youdisable VTP on the switch.

A VTP transparent switch does not send VTP updates and does not act on VTP updates received fromother switches. However, a VTP transparent switch running VTP version 2 does forward received VTPadvertisements out all of its trunk links.

Use the following commands, beginning in privileged EXEC mode, to disable VTP on the switch:

Verifying VTP

Use theshow vtp status command to verify VTP status, as shown in the following output example:

Router# show vtp status

VTP Version : 2Configuration Revision : 0Maximum VLANs supported locally : 256Number of existing VLANs : 8VTP Operating Mode : TransparentVTP Domain Name : NULLVTP Pruning Mode : DisabledVTP V2 Mode : DisabledVTP Traps Generation : DisabledMD5 digest : 0x99 0x04 0x23 0x53 0x35 0x77 0x0F 0xD0Configuration last modified by 10.1.1.1 at 3-1-02 00:23:59Router#

Note Theshow vtp status command shows the maximum VLANs supported by the router. Although thenumber might be higher for the router, the switch supports a maximum of 16 VLANs.

Command Purpose

Step 1 Router(config-if)# no interface vlanvlan _id

Removes the SVI interface corresponding to theVLAN.

Step 2 Router(config)# end Exits configuration mode.

Command Purpose


Step 2 Router(vlan)# vtp transparent Configures VTP transparent mode.

Step 3 Router(vlan)# exit Exits VLAN configuration mode.


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Configuring Spanning TreeThis section describes the configuration of Spanning Tree protocol on the switch, and contains thefollowing sections:

• Enabling Spanning Tree, page 27

• Configuring Spanning Tree Port Priority, page 28

• Configuring Spanning Tree Port Cost, page 29

• Configuring the Bridge Priority of a VLAN, page 29

• Configuring the Hello Time, page 30

• Configuring the Forward-Delay Time for a VLAN, page 30

• Configuring the Maximum Aging Time for a VLAN, page 31

• Configuring the Root Bridge, page 31

• Disabling Spanning Tree, page 32

Enabling Spanning Tree

You can enable Spanning Tree on a per-VLAN basis. The switch maintains a separate instance ofSpanning Tree for each VLAN (except on VLANs on which you disable Spanning Tree).

Use the following commands, in global configuration mode, to enable Spanning Tree on a per-VLANbasis:

Verifying Spanning Tree

Use theshow spanning-tree vlan to verify Spanning Tree configuration, as shown in the followingoutput example:

Router# show spanning - tree vlan 200VLAN200 is executing the ieee compatible Spanning Tree protocol Bridge Identifier has priority 32768, address 000b.be96.49a8 Configured hello time 2, max age 20, forward delay 15 We are the root of the spanning tree Topology change flag not set, detected flag not setNumber of topology changes 1 last change occurred 00:04:12 ago from FastEthernet4 Times: hold 1, topology change 35, notification 2 hello 2, max age 20, forward delay 15 Timers: hello 1, topology change 0, notification 0, aging 0

Command Purpose

Step 1 Router(config)# spanning - tree vlan vlan _ID Enables Spanning Tree protocol on a per-VLANbasis.



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Port 4 (FastEthernet4) of VLAN200 is forwarding Port path cost 19, Port priority 128, Port Identifier 128.4. Designated root has priority 32768, address 000b.be96.49a8 Designated bridge has priority 32768, address 000b.be96.49a8 Designated port id is 128.4, designated path cost 0 Timers: message age 0, forward delay 0, hold 0 Number of transitions to forwarding state: 1 BPDU: sent 141, received 0Router#

Configuring Spanning Tree Port Priority

Use the following commands, beginning in global configuration mode, to configure the Spanning Treeport priority of an interface.

Verifying Spanning Tree Port Priority

Use theshow spanning-tree interface to verify theSpanning Tree interface and the Spanning Tree portpriority configuration, as shown in the following output example:

Router# show spanning - tree interface fastethernet 3

Port 264 (FastEthernet3) of VLAN2 is forwarding Port path cost 19, Port priority 100, Port Identifier 129.8. Designated root has priority 32768, address 0010.0d40.34c7 Designated bridge has priority 32768, address 0010.0d40.34c7 Designated port id is 128.1, designated path cost 0 Timers: message age 2, forward delay 0, hold 0 Number of transitions to forwarding state: 1 BPDU: sent 0, received 13513Router#

Command Purpose

Step 1 Router(config)# interface fastethernet port Selects an interface to configure.

Step 2 Router(config-if)#[ no ] spanning - treeport - priority port _priority

Configures the port priority for an interface. Theport_priority value can be from 1 to 255 inincrements of 4.

Use theno form of this command to restore thedefaults.

Step 3 Router(config-if)#[ no ] spanning - tree vlanvlan _ID port - priority port _priority

Configures the VLAN port priority for an interface.The port_priority value can be from 1 to 255 inincrements of 4.




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Configuring Spanning Tree Port Cost

Use the following commands, beginning in global configuration mode, to configure the Spanning Treeport cost of an interface:

Verifying Spanning Tree Port Cost

Use theshow spanning-tree vlan command to verify theSpanning Tree port costconfiguration, as shownin the following output example:

Router# show spanning - tree vlan 200!Port 264 (FastEthernet3) of VLAN200 is forwardingPort path cost 17, Port priority 64, Port Identifier 129.8. Designated root has priority 32768, address 0010.0d40.34c7 Designated bridge has priority 32768, address 0010.0d40.34c7 Designated port id is 128.1, designated path cost 0 Timers: message age 2, forward delay 0, hold 0 Number of transitions to forwarding state: 1 BPDU: sent 0, received 13513!Router#

Configuring the Bridge Priority of a VLAN

Caution Be careful when using this command. For most situations thespanning-tree vlanvlan_ID root primaryand thespanning-tree vlanvlan_ID root secondarycommands are the preferred commands to modifythe bridge priority.

Command Purpose

Step 1 Router(config)# interface fastethernet port Selects an interface to configure.

Step 2 Router(config-if)#[ no ] spanning - tree costport _cost

Configures the port cost for an interface. The value ofport_cost can be from 1 to 200,000,000 (1 to 65,535 inCisco IOS Releases 12.1(2)E and earlier).


Step 3 Router(config-if)#[ no ] spanning - tree vlanvlan _ID cost port _cost

Configures the VLAN port cost for an interface. Thevalue port_cost can be from 1 to 65,535.




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Use the following commands, in global configuration mode, to configure the Spanning Tree bridgepriority of a VLAN:

Verifying the Bridge Priority of a VLAN

Use theshow spanning-tree vlan bridge command to verify thebridge priority, as shown in thefollowing output example.

Router# show spanning-tree vlan 200 bridge brief

Hello Max FwdVlan Bridge ID Time Age Delay Protocol---------------- -------------------- ---- ---- ----- --------VLAN200 33792 0050.3e8d.64c8 2 20 15 ieeeRouter#

Configuring the Hello Time

Use the following commands, in global configuration mode, to configure the hello interval for theSpanning Tree.

Configuring the Forward-Delay Time for a VLAN

Use the following commands, in global configuration mode, to configure the forward delay for theSpanning Tree:

Command Purpose

Step 1 Router(config)#[ no ] spanning - tree vlanvlan _ID priority bridge _priority

Configures the bridge priority of a VLAN. Thebridge_priority value can be from 1 to 65535.

Use theno keyword to restore the defaults.


Command Purpose

Step 1 Router(config)#[ no ] spanning - tree vlanvlan _ID hello - time hello _t ime

Configures the hello time of a VLAN. Thehello_timevalue can be from 1 to 10 seconds.



Command Purpose

Step 1 Router(config)#[ no ] spanning - tree vlanvlan _ID forward - time forward _time

Configures the forward time of a VLAN. The valueof forward _time can be from 4 to 30 seconds.




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Configuring the Maximum Aging Time for a VLAN

Use the following commands, in global configuration mode, to configure the maximum age interval forthe Spanning Tree:

Configuring the Root Bridge

The Ethernet switch maintains a separate instance of Spanning Tree for each active VLAN configuredon the switch. A bridge ID, consisting of the bridge priority and the bridge MAC address, is associatedwith each instance. For each VLAN, the switch with the lowest bridge ID will become the root bridgefor that VLAN.

To configure a VLAN instance to become the root bridge, the bridge priority can be modified from thedefault value (32768) to a significantly lower value so that the bridge becomes the root bridge for thespecified VLAN. Use thespanning-tree vlanvlan-ID root command to alter the bridge priority.

The switch checks the bridge priority of the current root bridges for each VLAN. The bridge priority forthe specified VLANs is set to 8192 if this value will cause the switch to become the root for the specifiedVLANs.

If any root switch for the specified VLANs has a bridge priority lower than 8192, the switch sets thebridge priority for the specified VLANs to 1 less than the lowest bridge priority.

For example, if all switches in the network have the bridge priority for VLAN 100 set to the default valueof 32768, entering thespanning-tree vlan100 root primary command on a switch will set the bridgepriority for VLAN 100 to 8192, causing the switch to become the root bridge for VLAN 100.

Note The root switch for each instance of Spanning Tree should be a backbone or distribution switch. Do notconfigure an access switch as the Spanning Tree primary root.

Use the diameter keyword to specify the Layer 2 network diameter (that is, the maximum number ofbridge hops between any two end stations in the Layer 2 network). When you specify the networkdiameter, the switch automatically picks an optimal hello time, forward delay time, and maximum agetime for a network of that diameter, which can significantly reduce the Spanning Tree convergence time.You can use the hello keyword to override the automatically calculated hello time.

Note We recommend that you avoid configuring the hello time, forward delay time, and maximum age timemanually after configuring the switch as the root bridge.

Command Purpose

Step 1 Router(config)#[ no ] spanning - tree vlanvlan _ID max- age max_age

Configures the maximum aging time of a VLAN. Thevalue ofmax_age can be from 6 to 40 seconds.




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Use the following commands, in global configuration mode, to configure the switch as the root:

Disabling Spanning Tree

Use the following commands, in global configuration mode, to disable Spanning Tree on a per-VLANbasis.

Verifying that Spanning Tree Is Disabled

Use theshow spanning-tree vlan command to verify thethat theSpanning Tree is disabled, as shownin the following output example:

Router# show spanning - tree vlan 200<...output truncated...>Spanning tree instance for VLAN 200 does not exist.Router#

Configuring Cisco Discovery Protocol (CDP)This section describes the following features of Cisco Discovery Protocol:

• Configuring Cisco Discovery Protocol (CDP), page 32

• Enabling CDP on an Interface, page 33

• Monitoring and Maintaining CDP, page 34

Configuring Cisco Discovery Protocol (CDP)

Use the following command, in global configuration mode, to enable CDP globally:

Command Purpose

Step 1 Router(config)#[ no ] spanning - tree vlanvlan_ID root primary [ diameter hops[ hello - time seconds ]]

Configures a switch as the root switch.



Command Purpose

Step 1 Router(config)# no spanning - tree vlanvlan _ID

Disables Spanning Tree on a per-VLAN basis.


Command PurposeRouter(config)#[ no ] cdp run Enables CDP globally. Use the no keyword to disable

CDP.


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Verifying the CDP Global Configuration

Use theshow cdpcommand to verify the CDP configuration, as shown in the following output example:

Router# show cdp

Global CDP information: Sending CDP packets every 120 seconds Sending a holdtime value of 180 seconds Sending CDPv2 advertisements is enabledRouter#

Enabling CDP on an Interface

Use the following command, in interface configuration mode, to enable CDP on an interface:

The following example shows how to enable CDP on Fast Ethernet interface 3:

Router(config)# interface fastethernet 3Router(config-if)# cdp enable

Verifying the CDP Interface Configuration

Use theshow cdp interfacecommand toverify the CDP configuration for an interface, as shown in thefollowing output example:

Router# show cdp interface fastethernet 3

FastEthernet3 is up, line protocol is up Encapsulation ARPA Sending CDP packets every 120 seconds Holdtime is 180 secondsRouter#

Verifying CDP Neighbors

Use theshow cdp neighborscommand toverify information about the neighboring equipment, as shownin the following output example:

Router# show cdp neighbors

Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge S - Switch, H - Host, I - IGMP, r - RepeaterDevice ID Local Intrfce Holdtme Capability Platform Port IDR51-C13-3524 Fas 1 159 T S WS-C3524-PFas 0/21orig_callgen Fas 2 160 R 3640 Fas 1/07200_1 Fas 3 177 R T 7206VXR Fas 0/0

Command PurposeRouter(config-if)# cdp enable Enables CDP on an interface.


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Monitoring and Maintaining CDP

Use one or more of the following commands, beginning in privileged EXEC mode, to monitor andmaintain CDP on your device:

Verifying the Switch Port ConfigurationFollow these steps to verify the switch port configuration:

Step 1 Use theshow run interfacecommand to verify the switch port configuration:

Router# show run interface < interface >

Step 2 Use thewrite memory command to save the current configuration in Flash memory:

Router# write memory

Configuring IP InformationThis section describes how to assign IP information on the Ethernet switch. The following topics areincluded:

• Assigning IP Information to the Switch, page 35

• Specifying a Domain Name and Configuring the DNS, page 36

Command PurposeRouter# clear cdp counter s Resets the traffic counters to zero.

Router# clear cdp table Deletes the CDP table of information about neighbors.

Router# show cdp Verifies global information such as frequency oftransmissions and the holdtime for packets beingtransmitted.

Router# show cdp entry entry _name [ protocol| version ]

Verifies information about a specific neighbor. Thedisplay can be limited to protocol version information.

Router# show cdp interface port Verifies information about interfaces on which CDP isenabled.

Router# show cdp neighbors port detail Verifies information about neighbors. The display canbe limited to neighbors on a specific interface and canbe expanded to provide more detailed information.

Router# show cdp traffic Verifies CDP counters, including the number ofpackets sent and received and checksum errors.


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Assigning IP Information to the Switch

You can use a BOOTP server to automatically assign IP information to the switch; however, the BOOTPserver must be set up in advance with a database of physical MAC addresses and corresponding IPaddresses, subnet masks, and default gateway addresses. In addition, the switch must be able to accessthe BOOTP server through one of its ports.

At startup, a switch without an IP address requests the information from the BOOTP server; therequested information is saved in the switch running the configuration file. To ensure that the IPinformation is saved when the switch is restarted, save the configuration by entering thewrite memorycommand in privileged EXEC mode.

You can change the information in these fields. The mask identifies the bits that denote the networknumber in the IP address. When you use the mask to subnet a network, the mask is then referred to as asubnet mask. The broadcast address is reserved for sending messages to all hosts. The CPU sends trafficto an unknown IP address through the default gateway.

Use the following commands, beginning in privileged EXEC mode, to enter the IP information:

Note Using theno ip addresscommand in configuration mode disables the IP protocol stack and removes theIP information. Cluster members without IP addresses rely on the IP protocol stack being enabled.

Use the following commands, beginning in global configuration mode, to remove an IP address from theswitch:

Caution If you are removing the IP address through a Telnet session, your connection to the switch will be lost.

Command Purpose

Step 1 Router# configure terminal Enters global configuration mode.

Step 2 Router(config)# interface vlan 1 Enter interface configuration mode, and enter theVLAN to which the IP information is assigned.VLAN 1 is the management VLAN, but you canconfigure any VLAN from IDs 1 to 1001.

Step 3 Router(config)# ip address ip_addresssubnet_mask

Enters the IP address and subnet mask.

Step 4 Router(config)# exit Returns to global configuration mode.

Step 5 Router# ip default-gateway ip_address Enters the IP address of the default router.

Step 6 Router# end Returns to privileged EXEC mode.

Command Purpose

Step 1 Router(config)# interface vlan 1 Enters interface configuration mode, and enters theVLAN to which the IP information is assigned.VLAN 1 is the management VLAN, but you canconfigure any VLAN from IDs 1 to 1001.

Step 2 Router(config-subif)# no ip address Removes the IP address and subnet mask.

Step 3 Router(config-subif)# end Returns to privileged EXEC mode.


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Specifying a Domain Name and Configuring the DNS

Each unique IP address can have a host name associated with it. The Cisco IOS software maintains a ECmode, and related Telnet support operations. This cache speeds the process of converting names toaddresses.

IP defines a hierarchical naming scheme that allows a device to be identified by its location or domain.Domain names are pieced together with periods (.) as the delimiting characters. For example, CiscoSystems is a commercial entity that IP identifies by acom domain name, so its domain name iscisco.com. A specific device in this domain, the FTP system, for example, is identified asftp.cisco.com.

To track domain names, IP has defined the concept of a domain name system (DNS), the purpose ofwhich is to hold a cache (or database) of names mapped to IP addresses. To map domain names to IPaddresses, you must first identify the host names and then specify a name server and enable the DNS,the Internet’s global naming scheme that uniquely identifies network devices.

Specifying the Domain Name

You can specify a default domain name that the software uses to complete domain name requests. Youcan specify either a single domain name or a list of domain names. When you specify a domain name,any IP host name without a domain name has that domain name appended to it before being added to thehost table.

Specifying a Name Server

You can specify up to six hosts that can function as a name server to supply name information for theDNS.

Enabling the DNS

If your network devices require connectivity with devices in networks for which you do not control nameassignment, you can assign device names that uniquely identify your devices within the entireinternetwork. The Internet’s global naming scheme, the DNS, accomplishes this task. This service isenabled by default.

Configuration ExamplesThis section provides the following configuration examples:

• Range of Interface Examples, page 37

• Optional Interface Feature Examples, page 37

• VLAN Configuration Example, page 38

• Disabling VTP (VTP Transparent Mode) Example, page 38

• Spanning Tree Examples, page 38

• Inter-VLAN Routing Example, page 40


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Range of Interface Examples

Single Range Configuration Example

The following example shows all Fast Ethernet interfaces being reenabled:

Router(config)# int range fastEthernet 1 - 4Router(config-if-range)# no shutRouter(config-if-range)#*Mar 3 22:38:35.929: %LINK-3-UPDOWN: Interface FastEthernet1, changed state to up*Mar 3 22:38:35.933: %LINK-3-UPDOWN: Interface FastEthernet2, changed state to up*Mar 3 22:38:35.941: %LINK-3-UPDOWN: Interface FastEthernet3, changed state to up*Mar 3 22:38:35.949: %LINK-3-UPDOWN: Interface FastEthernet4, changed state to up*Mar 3 22:38:36.105: %DTP-5-TRUNKPORTON: Port Fa4 has become dot1q trunk*Mar 3 22:38:36.589: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan1, changed stateto up*Mar 3 22:38:36.597: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan2, changed stateto up*Mar 3 22:38:36.933: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet2,changed state to up*Mar 3 22:38:36.941: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet3,changed state to up*Mar 3 22:38:36.949: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet4,changed state to upRouter(config-if-range)#

Range Macro Definition Example

The following example shows an interface-range macro named enet_list being defined to selectFast Ethernet interfaces 1 through 4:

Router(config)# define interface-range enet_list fastethernet 1 - 4

Router(config)#

The following example shows how to change to the interface-range configuration mode using theinterface-range macro enet_list:

Router(config)# interface range macro enet _list

Optional Interface Feature Examples

Interface Speed Example

The following example shows the interface speed being set to 100 Mbps on Fast Ethernet interface 4:

Router(config)# interface fastethernet 4

Router(config-if)# speed 100

Setting the Interface Duplex Mode Example

The following example shows the interface duplex mode being set to full on Fast Ethernet interface 4:

Router(config)# interface fastethernet 4

Router(config-if)# duplex full


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Adding a Description for an Interface Example

The following example shows how to add a description of Fast Ethernet interface 4:

Router(config)# interface fastethernet 4Router(config-if)# description Link to root switch

Configuring an Ethernet Interface as a Layer 2 Trunk Example

The following example shows how to configure the Fast Ethernet interface 4 as an 802.1Q trunk. Thisexample assumes that the neighbor interface is configured to support 802.1Q trunking.

Router# configure terminalEnter configuration commands, one per line. End with CNTL/Z.Router(config)# interface fastethernet 4Router(config-if)# shutdownRouter(config-if)# switchport trunk encapsulation dot1qRouter(config-if)# switchport mode trunkRouter(config-if)# no shutdownRouter(config-if)# endRouter# exit

VLAN Configuration Example

The following example shows how to configure the VLAN:

Router# vlan databaseRouter(vlan)# vlan 3VLAN 3 added:Name: VLAN0003Router(vlan)# exitAPPLY completed.Exiting....

Disabling VTP (VTP Transparent Mode) Example

The following example shows how to configure the switch as VTP transparent:

Router# vlan databaseRouter(vlan)# vtp transparentSetting device to VTP TRANSPARENT mode.Router(vlan)# exitAPPLY completed.Exiting....

Spanning Tree Examples

The following example shows Spanning Tree being enabled on VLAN 200:

Router# configure terminalRouter(config)# spanning - tree vlan 200Router(config)# endRouter#

Note Because Spanning Tree is enabled by default, issuing ashow running command to view the resultingconfiguration will not display the command you entered to enable Spanning Tree.


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The following example shows Spanning Tree being disabled on VLAN 200:

Router# configure terminalRouter(config)# no spanning - tree vlan 200Router(config)# endRouter#

Spanning-Tree Interface and Spanning-Tree Port Priority Example

The following example shows the VLAN port priority of an interface being configured:

Router# configure terminalRouter(config)# interface fastethernet 3Router(config-if)# spanning - tree vlan 200 port - priority 64Router(config-if)# endRouter#

The following example shows how to verify the configuration of VLAN 200 on the interface when it isconfigured as a trunk port:

Router# show spanning - tree vlan 200!Port 264 (FastEthernet3) of VLAN200 is forwardingPort path cost 19, Port priority 64, Port Identifier 129.8. Designated root has priority 32768, address 0010.0d40.34c7 Designated bridge has priority 32768, address 0010.0d40.34c7 Designated port id is 128.1, designated path cost 0 Timers: message age 2, forward delay 0, hold 0 Number of transitions to forwarding state: 1 BPDU: sent 0, received 13513Router#

Spanning-Tree Port Cost Example

The following example shows how to change the Spanning Tree port cost of a Fast Ethernet interface:

Router# configure terminalRouter(config)# interface fastethernet 3Router(config-if)# spanning - tree cost 18Router(config-if)# endRouter#

The following example shows how to configure the Spanning Tree VLAN port cost of a Fast Ethernetinterface:

Router# configure terminalRouter(config)# interface fastethernet 3Router(config-if)# spanning - tree vlan 200 cost 17Router(config-if)# exit

The following example shows how to verify the configuration of the interface when it is configured asan access port:

Router# show spanning - tree interface fastethernet 3 Port 264 (FastEthernet3) of VLAN200 is forwarding Port path cost 18, Port priority 100, Port Identifier 129.8. Designated root has priority 32768, address 0010.0d40.34c7 Designated bridge has priority 32768, address 0010.0d40.34c7 Designated port id is 128.1, designated path cost 0 Timers: message age 2, forward delay 0, hold 0 Number of transitions to forwarding state: 1 BPDU: sent 0, received 13513Router#


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Bridge Priority of a VLAN

The following example shows the bridge priority of VLAN 200 being configured to 33792:

Router# configure terminalRouter(config)# spanning - tree vlan 200 priority 33792Router(config)# endRouter#

Hello Time Example

The following example shows the hello time for VLAN 200 being configured to 7 seconds:

Router# configure terminalRouter(config)# spanning - tree vlan 200 hello-time 7Router(config)# endRouter#

Forward-Delay Time for a VLAN Example

The following example shows the forward delay time for VLAN 200 being configured to 21 seconds:

Router# configure terminalRouter(config)# spanning - tree vlan 200 forward-time 21Router(config)# endRouter#

Maximum Aging Time for a VLAN Example

The following example configures the maximum aging time for VLAN 200 to 36 seconds:

Router# configure terminalRouter(config)# spanning - tree vlan 200 max - age 36Router(config)# endRouter#

Spanning Tree Root Example

The following example shows the switch being configured as the root bridge for VLAN 10, with anetwork diameter of 4:

Router# configure terminalRouter(config)# spanning - tree vlan 10 root primary diameter 4Router(config)# exitRouter#

Inter-VLAN Routing Example

Configuring inter-VLAN routing is identical to the configuration on an Ethernet switch with a MultilayerSwitch Feature Card (MSFC). Configuring an interface for WAN routing is consistent with other CiscoIOS platforms.

The following example provides a sample configuration:

Router# interface Vlan 160Router(config-if)# description voice vlanRouter(config-if)# ip address 10.6.1.1 255.255.255.0

Router(config)# interface Vlan 60Router(config-if)# description data vlanRouter(config-if)# ip address 10.60.1.1 255.255.255.0


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Related Documentation

Router(config-if)# interface Serial1/0Router(config-if)# ip address 160.3.1.2 255.255.255.0

Note Standard Interior Gateway Protocol (IGP) routing protocols such as Routing Information Protocol (RIP),Interior Gateway Routing Protocol (IGRP), Enhanced Interior Gateway Routing Protocol (EIGRP), andOpen Shortest Path First (OSPF) are supported on the Ethernet switch.

Related DocumentationRefer to the following documentation for additional information on the Cisco 1700 series routers:

• Cisco 1760 Router Hardware Installation Guide



• Cisco 1711 and Cisco 1712 Security Access Routers Hardware Installation Guide

• Cisco Interface Cards Installation Guide

Obtaining DocumentationCisco provides several ways to obtain documentation, technical assistance, and other technicalresources. These sections explain how to obtain technical information from Cisco Systems.

Cisco.comYou can access the most current Cisco documentation on the World Wide Web at this URL:

http://www.cisco.com/univercd/home/home.htm

You can access the Cisco website at this URL:

http://www.cisco.com

International Cisco websites can be accessed from this URL:

http://www.cisco.com/public/countries_languages.shtml

Documentation CD-ROMCisco documentation and additional literature are available in a Cisco Documentation CD-ROMpackage, which may have shipped with your product. The Documentation CD-ROM is updated regularlyand may be more current than printed documentation. The CD-ROM package is available as a single unitor through an annual or quarterly subscription.

Registered Cisco.com users can order a single Documentation CD-ROM (product numberDOC-CONDOCCD=) through the Cisco Ordering tool:

http://www.cisco.com/en/US/partner/ordering/ordering_place_order_ordering_tool_launch.html

http://www.cisco.com/univercd/cc/td/doc/product/access/acs_mod/1700/1700/1760/index.htm

http://www.cisco.com/univercd/cc/td/doc/product/access/acs_mod/1700/1751/1751hig/index.htm



http://www.cisco.com/univercd/cc/td/doc/product/access/acs_mod/cis2600/hw_inst/wic_inst/wic_doc/index.htm

http://www.cisco.com/univercd/home/home.htm

http://www.cisco.com

http://www.cisco.com/public/countries_languages.shtml



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Obtaining Technical Assistance

All users can order annual or quarterly subscriptions through the online Subscription Store:

http://www.cisco.com/go/subscription

Ordering DocumentationYou can find instructions for ordering documentation at this URL:

http://www.cisco.com/univercd/cc/td/doc/es_inpck/pdi.htm

You can order Cisco documentation in these ways:

• Registered Cisco.com users (Cisco direct customers) can order Cisco product documentation fromthe Networking Products MarketPlace:

http://www.cisco.com/en/US/partner/ordering/index.shtml

• Nonregistered Cisco.com users can order documentation through a local account representative bycalling Cisco Systems Corporate Headquarters (California, USA) at 408 526-7208 or, elsewhere inNorth America, by calling 800 553-NETS (6387).

Documentation FeedbackYou can submit comments electronically on Cisco.com. On the Cisco Documentation home page, clickFeedback at the top of the page.

You can send your comments in e-mail to [email protected].

You can submit comments by using the response card (if present) behind the front cover of yourdocument or by writing to the following address:

Cisco SystemsAttn: Customer Document Ordering170 West Tasman DriveSan Jose, CA 95134-9883

We appreciate your comments.

Obtaining Technical AssistanceFor all customers, partners, resellers, and distributors who hold valid Cisco service contracts, the CiscoTechnical Assistance Center (TAC) provides 24-hour, award-winning technical support services, onlineand over the phone. Cisco.com features the Cisco TAC website as an online starting point for technicalassistance.

Cisco TAC WebsiteThe Cisco TAC website (http://www.cisco.com/tac) provides online documents and tools fortroubleshooting and resolving technical issues with Cisco products and technologies. The Cisco TACwebsite is available 24 hours a day, 365 days a year.

Accessing all the tools on the Cisco TAC website requires a Cisco.com user ID and password. If youhave a valid service contract but do not have a login ID or password, register at this URL:

http://tools.cisco.com/RPF/register/register.do


http://www.cisco.com/go/subscription

http://www.cisco.com/univercd/cc/td/doc/es_inpck/pdi.htm

http://www.cisco.com/en/US/partner/ordering/index.shtml

http://www.cisco.com/tac



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Obtaining Additional Publications and Information

Opening a TAC CaseThe online TAC Case Open Tool (http://www.cisco.com/tac/caseopen) is the fastest way to open P3 andP4 cases. (Your network is minimally impaired or you require product information). After you describeyour situation, the TAC Case Open Tool automatically recommends resources for an immediate solution.If your issue is not resolved using these recommendations, your case will be assigned to a Cisco TACengineer.

For P1 or P2 cases (your production network is down or severely degraded) or if you do not have Internetaccess, contact Cisco TAC by telephone. Cisco TAC engineers are assigned immediately to P1 and P2cases to help keep your business operations running smoothly.

To open a case by telephone, use one of the following numbers:

Asia-Pacific: +61 2 8446 7411 (Australia: 1 800 805 227)EMEA: +32 2 704 55 55USA: 1 800 553-2447

For a complete listing of Cisco TAC contacts, go to this URL:

http://www.cisco.com/warp/public/687/Directory/DirTAC.shtml

TAC Case Priority DefinitionsTo ensure that all cases are reported in a standard format, Cisco has established case priority definitions.

Priority 1 (P1)—Your network is “down” or there is a critical impact to your business operations. Youand Cisco will commit all necessary resources around the clock to resolve the situation.

Priority 2 (P2)—Operation of an existing network is severely degraded, or significant aspects of yourbusiness operation are negatively affected by inadequate performance of Cisco products. You and Ciscowill commit full-time resources during normal business hours to resolve the situation.

Priority 3 (P3)—Operational performance of your network is impaired, but most business operationsremain functional. You and Cisco will commit resources during normal business hours to restore serviceto satisfactory levels.

Priority 4 (P4)—You require information or assistance with Cisco product capabilities, installation, orconfiguration. There is little or no effect on your business operations.

Obtaining Additional Publications and InformationInformation about Cisco products, technologies, and network solutions is available from various onlineand printed sources.

• The Cisco Product Catalog describes the networking products offered by Cisco Systems, as well asordering and customer support services. Access the Cisco Product Catalog at this URL:

http://www.cisco.com/en/US/products/products_catalog_links_launch.html

• Cisco Press publishes a wide range of networking publications. Cisco suggests these titles for newand experienced users: Internetworking Terms and Acronyms Dictionary, InternetworkingTechnology Handbook, Internetworking Troubleshooting Guide, and the Internetworking DesignGuide. For current Cisco Press titles and other information, go to Cisco Press online at this URL:

http://www.ciscopress.com


http://www.cisco.com/tac/caseopen

http://www.cisco.com/warp/public/687/Directory/DirTAC.shtml

http://www.cisco.com/en/US/products/products_catalog_links_launch.html



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Glossary

• Packet magazine is the Cisco quarterly publication that provides the latest networking trends,technology breakthroughs, and Cisco products and solutions to help industry professionals get themost from their networking investment. Included are networking deployment and troubleshootingtips, configuration examples, customer case studies, tutorials and training, certification information,and links to numerous in-depth online resources. You can access Packet magazine at this URL:

http://www.cisco.com/go/packet

• iQ Magazine is the Cisco bimonthly publication that delivers the latest information about Internetbusiness strategies for executives. You can access iQ Magazine at this URL:

http://www.cisco.com/go/iqmagazine

• Internet Protocol Journal is a quarterly journal published by Cisco Systems for engineeringprofessionals involved in designing, developing, and operating public and private internets andintranets. You can access the Internet Protocol Journal at this URL:

http://www.cisco.com/en/US/about/ac123/ac147/about_cisco_the_internet_protocol_journal.html

• Training—Cisco offers world-class networking training. Current offerings in network training arelisted at this URL:

http://www.cisco.com/en/US/learning/index.html

Glossary802.1p—IEEE standard for queuing and multicast support

802.1q—IEEE standard for VLAN frame tagging

AVVID —Architecture for Voice, Video, and Integrated Data

BPDU—bridge protocol data unit

CBAC—Context-based Access Control

CDP—Cisco Discovery Protocol

CoS—class of service

DSCP—Differentiated Services Code Point

IP—Internet Protocol

PSTN—public switched telephone network

QoS—quality of service

SNMP—Simple Network Management Protocol

STP—Spanning Tree Protocol

VLAN —virtual local area network

VoIP—Voice over IP

VPN—Virtual Private Network

VTP—VLAN Trunking Protocol

WAN—wide area network

WRR—weighted round-robin


http://www.cisco.com/go/packet

http://www.cisco.com/go/iqmagazine

http://www.cisco.com/en/US/about/ac123/ac147/about_cisco_the_internet_protocol_journal.html

http://www.cisco.com/en/US/learning/index.html


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Glossary

This document is to be used in conjunction with the documents listed in the“Related Documentation” section on page 41.

Copyright © 2003 Cisco Systems, Inc. All rights reserved.

CCSP, the Cisco Square Bridge logo, Cisco Unity, Follow Me Browsing, FormShare, and StackWise are trademarks of Cisco Systems, Inc.; Changing the Way We Work, Live, Play, and Learn, and iQuick Study are service marks of Cisco Systems, Inc.; and Aironet, ASIST, BPX, Catalyst, CCDA, CCDPCCIE, CCIP, CCNA, CCNP, Cisco, the Cisco Certified Internetwork Expert logo, Cisco IOS, Cisco Press, Cisco Systems, Cisco Systems Capital, the Cisco Systems logo, Empowering the Internet Generation, Enterprise/Solver, EtherChannel, EtherFast, EtherSwitch, Fast Step, GigaDrive, GigaStack, HomeLink, Internet Quotient, IOS, IP/TV, iQ Expertise, the iQ logo, iQ Net Readiness Scorecard, LightStream, Linksys, MeetingPlace, MGX, the Networkers logo, Networking Academy, Network Registrar, Packet, PIX, Post-Routing, Pre-Routing, ProConnect, RateMUX, Registrar, ScriptShare, SlideCast, SMARTnet, StrataView Plus, SwitchProbe, TeleRouter, The Fastest Way to Increase Your Internet Quotient, TransPath, and VCO are registered trademarks of Cisco Systems, Inc. and/or its affiliates in the United States and certain other countries.

All other trademarks mentioned in this document or Website are the property of their respective owners. The use of the word partner does not imply a partnership relationship between Cisco and any other company. (0406R)


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Glossary

cisco 1711

Documents