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Use of VLANs for IPv4-IPv6 Coexistence in Enterprise Networks

presented by leeh@ncnu.edu.tw

2007.05.14 tech3 R322

rfc 4554

2

VLAN Overview - 1

3rd floor

2nd floor

1st floor

SALES

ADMIN

ENG

physical LAN = A broadcast domain

3

VLAN Overview - 2

3rd floor

2nd floor

1st floor

SALES

ADMIN

ENG

physical LAN = A broadcast domain

!?

4

VLAN Overview - 3

3rd floor

2nd floor

1st floor

SALES ADMINENG

A VLAN = A broadcast domain = Logical network (subnet)

• Segmentation

• Flexibility

• Security

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VLAN Operations - 1

Switch A

ADMINVLAN

SALESVLAN

ENGVLAN

Switch B

ADMINVLAN

SALESVLAN

ENGVLAN

• Each logical VLAN is like a separate physical bridge• VLANs can span across multiple switches

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VLAN Operations - 2

• Each logical VLAN is like a separate physical bridge• VLANs can span across multiple switches• Trunks carries traffic for multiple VLANs

Trunk

Fast Ethernet

Switch A

ADMINVLAN

SALESVLAN

ENGVLAN

Switch B

ADMINVLAN

SALESVLAN

ENGVLAN

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For a LAN environment…IPv6 host IPv6 hostIPv4 host IPv4 host

Layer 2 switch

IPv6 host IPv6 host IPv4 host IPv4 host

Can be treated as separate LANs

noise noise noisenoise

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Routing works….

IPv6 host IPv4 host

Layer 2 switch

IPv6 only router

R1

IPv4 only router

R2

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Separate to 2 domains

IPv6 host IPv6 hostIPv4 host IPv4 host

Layer 2 switch

IPv6 host IPv6 host IPv4 host IPv4 host

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Pure IPv4/IPv6..

R

10 11 12 19

R

13 14 15 19 16 17 18 19

R

Data Link

Network

VLAN trunking

IPv6 hosts

Vlan 19

IPv4 only router IPv4 only router IPv6 only router

IPv6 hosts

Vlan 19

IPv6 hosts

Vlan 19

A case for providing pure IPv4 and pure IPv6 by using same physical link

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Congruent IPv4 and IPv6 subnets

IPv6 hostIPv4 host

Dual stack router

IPv4 /IPv6

R

Layer 2 switch

Dual stack host

12

A mix of IPv4 and IPv6 Solutions

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Cisco cmd: sh run int fa9/35

!interface FastEthernet9/35 description "R3-R0-1" no ip address switchport switchport access vlan 39 switchport mode accessend

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Cisco cmd: sh run int vlan39

interface Vlan39 description "Computer Classroom" ip address 10.10.39.254 255.255.255.0 ip access-group 139 in ip helper-address 163.22.2.3 no ip redirects no ip unreachables no ip proxy-arp ip route-cache flow ip igmp snooping querier ip policy route-map ADSL1!

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Cisco cmd: show vlan

39 VLAN0039 active Fa9/35

41 VLAN0041 active Gi7/43

47 VLAN0047 active Fa9/24

80 VLAN0080 active Fa9/18

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Example: Create vlan of Layer 2

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Example: Delete vlan of Layer 2

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Example: Delete vlan of Layer 2

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Example: create a routing interface

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Example: create a IPv6 routing interface

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Example: assign an interface to a vlan

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Example: assign an interface to a vlan

23取自　 http://solomon.ipv6.club.tw/Course/IPv6/ch2.pdf page5

try to remember…..

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Draft-ietf-ngtrans-isatap-13.txt

Intra-Site Automatic Tunnel Addressing Protocol (ISATAP)

取自　www.ipv6.org.tw/seminar/92_v6_training/2a.ppt

RFC 4212

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ISATAP

The primary function of ISATAP is to allow hosts that are multiple IPv4 hops away from an IPv6 router to participate in the IPv6 network by automatically tunneling IPv6 packets over IPv4 to the next-hop address.

Example: ISATAP host communicates with IPv6 host (no ISATAP support).

The ISATAP host is isolated in an IPv4 network whereas the IPv6 host is a IPv6 network

IPv4 IPv4 InfrastructureInfrastructure

HOST B ISATAPISATAPSupportedSupported

ISATAP IPv6 IPv6

NetworkNetwork

IPv6 HOST

取自　www.ipv6.org.tw/seminar/92_v6_training/2a.ppt

26

ISATAP

27

ISATAP

In the reverse direction, the ISATAP router automatically performs IPv6-in-IPv4 tunneling for packets from the native IPv6 host to the ISATAP host even though the native IPv6 host has no knowledge of the legacy IPv4 infrastructure or addressing architecture.

IPv4 IPv4 InfrastructureInfrastructure

HOST B ISATAPISATAPSupportedSupported

ISATAP IPv6 IPv6

NetworkNetwork

IPv6 HOST

取自　www.ipv6.org.tw/seminar/92_v6_training/2a.ppt

28

Construction of ISATAP addressISATAP interface identifier can be combined with any 64-bit prefix (including 6to4 prefixes) to form an RFC 2373 compliant IPv6 globally aggregatable unicast address.

IPv4 address inside EUI-64 interface identifier

::0:5EFE:A.B.C.D for IPv4 address A.B.C.D

The 0:5EFE portion is formed from the combination of the

Oganizational Unit Identifier (OUI) that is assigned to IANA,

and a type that indicates an embedded IPv4 address (FE).

Interface IdentifierPrefix

ISATAP Prefix Specially constructed EUI64 Interface ID

64-bits 64-bits

ISATAP Address Format

取自　www.ipv6.org.tw/seminar/92_v6_training/2a.ppt

29

ISATAP Address Example

If TYPE = 0xFF and TSE = 0xFE, TSD contains legacy EUI48 (TSE = 0xFF reserved by IEEE).If TYPE = 0xFE, TSE and TSD together contain embedded IPv4 address.

IPv4 address is: 140.173.129.3 routing prefix is: 3FFE:1A05:510:2412

ISATAP IPv6 address is:

OUI Extension ID24-bits 40-bits

EUI-64 Format Interface Identifier

00 00 5e TYPE TSE TSD

:0:5EFE:3FFE:1A05:510:2412 140.173.129.3

Link-local variant is: FE80::0:5EFE:140.173.129.3

Specially constructed EUI64 Interface IDSpecially constructed EUI64 Interface ID

取自　www.ipv6.org.tw/seminar/92_v6_training/2a.ppt

30

ISATAP OperationSimple Deployment Scenario of ISATAP (Hosts….)

The Automatic Tunneling Pseudo-Interface uses the link-local ISATAP address assigned to the interface as a source, and uses the last 32 bits in the source and destination IPv6 addresses (corresponding to the embedded IPv4 addresses) as the source and destination IPv4 addresses

FE80::5EFE:10.40.1.29IPv4 IPv4

InfrastructureInfrastructureIPv6Header

IPv6Data

IPv6Header

IPv6Data

IPv4Header

192.168.41.3010.40.1.29

FE80::5EFE:192.168.41.30

HOST A ISATAPISATAPSupportedSupported

HOST B ISATAPISATAPSupportedSupported

IPv6Header

IPv6Data

Src = FE80::5EFE:10.40.1.29Dst = FE80::5EFE:192.168.41.30

Src = FE80::5EFE:10.40.1.29Dst = FE80::5EFE:192.168.41.30

Src = 10.40.1.29Dst = 192.68.41.30

取自　www.ipv6.org.tw/seminar/92_v6_training/2a.ppt

31

ISATAP Operation

Simple Deployment Scenario of ISATAP (Routers…)

IPv6 IPv6 NetworkNetwork

IPv4 IPv4 NetworkNetwork

IPv6 in IPv4ISATAP

IPv6 HOST

ISATAP HOST

3FFE:1A05:5102412:5EFE:10.40.1.2910.40.1.29

IPv6Header

IPv6Data

3FFE:1A05:5102412:5EFE:192.168.41.25

192.168.41.25

IPv6Header

IPv6Data

IPv4Header

IPv6Header

IPv6Data

Src = 3FFE:1A05:5102412:5EFE:10.40.1.29Dst = 3FFE:3600:8::1

Src = 10.40.1.29Dst = 192.68.41.25

Src = 3FFE:1A05:5102412:5EFE:10.40.1.29Next = 3FFE:1A05:5102412:5EFE:192.168.41.25Dst = 3FFE:3600:8::1

取自　www.ipv6.org.tw/seminar/92_v6_training/2a.ppt

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Thank you!