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VLANVLAN

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What Do We Mean byWhat Do We Mean by

Bandwidth Management?Bandwidth Management?Brings back router Brings back router--oriented benefits into our networksoriented benefits into our networks

while improving upon router deficiencieswhile improving upon router deficiencies

Classic router benefitsClassic router benefits

± ± Broadcast containment and policyBroadcast containment and policyEnforcement (security)Enforcement (security)

Classic router deficienciesClassic router deficiencies ± ± Change managementChange management

± ± Complex administrationComplex administration

± ± CostCost

How?How?

Layer 3 handling, VLANs, routing, filtering, ...Layer 3 handling, VLANs, routing, filtering, ...

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VLANs for Bandwidth AllocationVLANs for Bandwidth Allocation

ConfigurationConfiguration

MembershipMembership

CriteriaCriteria

ManagementManagement

Explicit and ImplicitExplicit and ImplicitSpanningSpanning

BoxesBoxes

Defines Membership PoliciesDefines Membership Policies

There¶s More to VLAN Technology than TaggingThere¶s More to VLAN Technology than Tagging

Level of Level of

Automation Automation

LogicalLogical

ViewsViews

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PolicyPolicy--Based Virtual LANsBased Virtual LANs Defines membership policiesDefines membership policies

Flexible VLAN policy definitionFlexible VLAN policy definition ± ± Port groupingPort grouping

± ± M AC address groupingM AC address grouping ± ± Protocol groupingProtocol grouping

± ± Application control Application control

Mature technologyMature technology

Backbone LANBackbone LAN

Port GroupPort Group

Address Groups Address Groups

Protocol GroupProtocol Group

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ProtocolProtocol--Based VLAN DefinitionsBased VLAN Definitions

IPIP

IPXIPX

NetBIOSNetBIOS

Subnet 1 Subnet 4

Subnet 2

VLANs defined byVLANs defined byexisting paradigmsexisting paradigms ± ± Layer 3 ID,Layer 3 ID,

layer 2 simplicitylayer 2 simplicity

Support for routable andSupport for routable andnonnon--routable protocolsroutable protocols ± ± IP subnet, AppleTalk, IPX,IP subnet, AppleTalk, IPX,

DECnet, NetBIOS,DECnet, NetBIOS,Netbeui, XNS, SNA,Netbeui, XNS, SNA,Vines, X.25, andVines, X.25, and WildcardWildcard

NonNon--proprietaryproprietaryimplementationimplementation

Subnet 7

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How Does Routing Fit In?How Does Routing Fit In?Q: Why?Q: Why?

A1: You can¶t flatten a network overnight A1: You can¶t flatten a network overnight

A2: Routing allows directed unicasts to traverse VLANs A2: Routing allows directed unicasts to traverse VLANs

1 2

RoutingRouting

BridgingBridging

VLANVLAN--BB

VLANVLAN-- A A

RR

3 4

IP Subnet A =

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Where Should the Router Reside?Where Should the Router Reside? Inside the Switch: Multinetting, Per Inside the Switch: Multinetting, Per--portport

configuration, ASIC+RISC preprocessing,configuration, ASIC+RISC preprocessing,no Hops, no links, lower costno Hops, no links, lower cost

Outside the Switch: More routing protocolsOutside the Switch: More routing protocols

ExternalExternalRouter Router

SwitchSwitch

VLANVLAN--BBVLANVLAN-- A A

RR

5

BB

3 41 2

InternalInternalRoutingRouting

BridgingBridging

VLANVLAN--BBVLANVLAN-- A A

RR

BB

3 41 2

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Routing/VLAN StructureRouting/VLAN Structure Logical protocolLogical protocol--basedbasedVLAN enginesVLAN engines

Route between VLANsRoute between VLANs ± ± IP, IPX, AppletalkIP, IPX, Appletalk

Switch within VLANsSwitch within VLANs

Flexibly combined withFlexibly combined with

other definition optionsother definition options ASIC accelerated ASIC accelerated

RoutingRoutingEngineEngine

SwitchingSwitchingEngineEngine SSSS

M AC M ACM AC

VLAN EngineVLAN Engine VLAN EngineVLAN Engine

158.101.20.X158.101.20.X 158.101.10.X158.101.10.X

158.101.10.1158.101.10.1158.101.10.2158.101.10.2158.101.20.1158.101.20.1

158.101.20.2158.101.20.2 158.101.20.3158.101.20.3

RR

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Using ProtocolUsing Protocol--Based VLANsBased VLANs

to Allocate Bandwidthto Allocate Bandwidth

IP Subnet A

AT Network

IPIP--BasedBased

FileserversFileservers

AppleTalk Must Be AppleTalk Must Be

Supported on a MajoritySupported on a Majority--IP LANIP LAN

Support AppleTalk,but isolate it

Broadcast ContainmentBroadcast Containment

VLANs vs. FiltersVLANs vs. Filters

VLAN AdvantageVLAN Advantage

± ± Protocol dependentProtocol dependent

± ± Less maintenanceLess maintenance

Address filter advantage Address filter advantage

± ± Simple, clear Simple, clear

User BenefitsUser Benefits

Support required protocolsSupport required protocols

Optimize response time for other protocolsOptimize response time for other protocols

IP Subnet A

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Using ProtocolUsing Protocol--Based VLANs toBased VLANs to

Allocate Bandwidth Allocate BandwidthBroadcast FirewallsBroadcast Firewalls

IPIP--BasedBased

FileserversFileservers


VLAN advantageVLAN advantage

± ± Easily span boxesEasily span boxes


Port groupPort groupfilter advantagefilter advantage

± ± Simple, clear Simple, clear


Improved application and desktop response timeImproved application and desktop response time

Reduce exposure to lab broadcast stormsReduce exposure to lab broadcast storms

IP Subnet A

Support AppleTalk,but isolate it

IP Subnet A

NetBIOS

Test LabTest Lab

Generating NetBIOS TrafficGenerating NetBIOS Traffic

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Using ProtocolUsing Protocol--Based VLANsBased VLANs

to Enforce Policyto Enforce PolicyRestricted Subnet AccessRestricted Subnet Access

IP Subnet AIP Subnet A


HR Server;HR Server;


Only Members of ³IP Subnet A´ VLANcan Access HR Server

Engineering Server;Engineering Server;

IP subnet BIP subnet B

IP Subnet BIP Subnet B


VLAN advantageVLAN advantage


± ± Less maintenanceLess maintenance

Address group Address group

filter advantagefilter advantage ± ± Tighter securityTighter security


Policy enforcement for secure accessPolicy enforcement for secure access


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Using ProtocolUsing Protocol--Based VLANs to EaseBased VLANs to Ease

the Adds/Moves/Change Problemthe Adds/Moves/Change ProblemMoving an IP DeviceMoving an IP Device -- No Station ReconfigurationNo Station Reconfiguration

IP Subnet A

IP Subnet B


7

9

5

9

4

IP Subnet A

User Needs to MoveUser Needs to Move

Across Building Across Building

User BenefitUser Benefit

No workstation changes neededNo workstation changes needed

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VLANs on the BackplaneVLANs on the Backplane

RISC

Inter swich Link (ISL)Inter swich Link (ISL)

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Relationship between VLANs and ELANsRelationship between VLANs and ELANs ELANs are simply another switch portELANs are simply another switch port

± ± ELANs are flat, fast and simple,ELANs are flat, fast and simple, butbut suffer the samesuffer the samebroadcast issues asbroadcast issues as

Bandwidth issues addressed by same techniquesBandwidth issues addressed by same techniques ± ± Filters, VLANs, IP Multicasting, Integral RoutingFilters, VLANs, IP Multicasting, Integral Routing

VLANs particularly sensible in ATMVLANs particularly sensible in ATM ± ± Each ELAN is a ³Virtual´ path to begin withEach ELAN is a ³Virtual´ path to begin with

± ± ELAN configuration is flexibleELAN configuration is flexible

± ± ELAN

s are meant to be parallelELAN

s are meant to be parallel The same issues driving high function switchingThe same issues driving high function switching

apply to (LANEapply to (LANE--based) ATM networksbased) ATM networks

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TELSYS TELSYS

vlan_p

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