IS-IS IPv6 Cisco IOS

For generel IS-IS and IS-IS for Ipv4 see IS-IS

Configuring IPv6 IS-IS

IPv4/IPv6 Dualstack example

interface FastEthernet0/1
 ip address 10.14.0.2 255.255.255.0
 ip router isis
 ipv6 address 2001:10:14::2/64
 ipv6 router isis
 isis circuit-type level-2-only
!
router isis
 net 49.0000.0100.1125.5255.00
 metric-style wide
 passive-interface FastEthernet2/0

Enabling IPv6 on IPv4 networks

When enabling IPv6 IS-IS between two neighbors running IPv4 the adjacency is broken if not both Routers have IPv4 and IPv6 enabled simultaneously.

To avoid this situation it's necessary - at least temporarily - to disable adjacency check on IS-IS on all routers before IPv6 enabling.

Example

router isis
 net 49.0000.0100.1125.5255.00
 is-type level-2-only
 metric-style wide
 passive-interface FastEthernet2/0
 !
 address-family ipv6
 <notice>no adjacency-check</notice>
 exit-address-family
!

IPv6 IS-IS through IPv4 only islands

Because IS-IS uses CLNP and not IPv6 a standard IPv6-over-IPv4-Tunnel can't be used. A GRE tunnel through IPv4 is necessary.

Building the tunnel

R1

hostname R1
!
interface Tunnel10
 description GRE tunnel over IPv4-only network to R2
 ip address 192.168.218.1 255.255.255.0
 ip router isis
 ipv6 address 2001:16D8:DD85:A600::1/64
 ipv6 enable
 ipv6 router isis
 isis circuit-type level-2-only
 tunnel source FastEthernet0/1
 tunnel destination 91.16.45.44
!
interface Loopback0
 ip address 192.168.217.1 255.255.255.255
 ip router isis
 ipv6 address 2001:16D8:DD85:A501::1/128
 ipv6 router isis
 isis circuit-type level-2-only
!
interface FastEthernet0/1
 description Connection to IPv4 only network
 ip address 83.90.56.5 255.255.255.252
!
router isis
 net 49.0000.1921.6821.7002.00
 is-type level-2-only
 metric-style wide
!
router bgp 3642
 bgp router-id 192.168.217.1
 no bgp default ipv4-unicast
 neighbor PG-IPv6 peer-group
 neighbor PG-IPv6 remote-as 3642
 neighbor PG-IPv6 update-source Loopback0
 neighbor PG-IPv4 peer-group
 neighbor PG-IPv4 remote-as 3642
 neighbor PG-IPv4 update-source Loopback0
 neighbor 2001:16D8:DD85:A600::2 peer-group PG-IPv6
 neighbor 192.168.225.1 peer-group PG-IPv4
 !
 address-family ipv4
 neighbor 192.168.225.1 activate
 no auto-summary
 no synchronization
 exit-address-family
 !
 address-family ipv6
 neighbor 2001:16D8:DD85:A600::2 activate
 exit-address-family

R2

hostname R2
!
interface Tunnel10
 description GRE tunnel over IPv4-only network to R1
 ip address 192.168.226.1 255.255.255.0
 ip router isis
 ipv6 address 2001:16D8:DD85:A600::2/64
 ipv6 enable
 ipv6 router isis
 isis circuit-type level-2-only
 tunnel source FastEthernet0/1
 tunnel destination 83.90.56.5
!
interface Loopback0
 ip address 192.168.225.1 255.255.255.255
 ip router isis
 ipv6 address 2001:16D8:DD85:A701::1/128
 ipv6 router isis
 isis circuit-type level-2-only
!
interface FastEthernet0/1
 description Connection to IPv4 only network
 ip address 91.16.45.44 255.255.255.252
!
router isis
 net 49.0000.1921.6822.5001.00
 is-type level-2-only
 metric-style wide
!
router bgp 3642
 bgp router-id 192.168.225.1
 no bgp default ipv4-unicast
 neighbor PG-IPv6 peer-group
 neighbor PG-IPv6 remote-as 3642
 neighbor PG-IPv6 update-source Loopback0
 neighbor PG-IPv4 peer-group
 neighbor PG-IPv4 remote-as 3642
 neighbor PG-IPv4 update-source Loopback0
 neighbor 2001:16D8:DD85:A501::1 peer-group PG-IPv6
 neighbor 192.168.217.1 peer-group PG-IPv4
 !
 address-family ipv4
 neighbor PEER next-hop-self
 neighbor 192.168.217.1 activate
 no auto-summary
 no synchronization
 exit-address-family
 !
 address-family ipv6
 neighbor 2001:16D8:DD85:A501::1 activate
 exit-address-family

Testing

CLNS throgh tunnel

R2#<input>show clns neighbors</input>
System Id      Interface   SNPA                State  Holdtime  Type Protocol
R1      <notice>Tu10</notice>        83.90.56.5       Up     28        <notice>L2</notice>   IS-IS

Testing

R2#<input>traceroute clns  49.0000.1921.6821.7002.00</input>

Type escape sequence to abort.
Tracing the route to 49.0000.1921.6821.7002.00
  1 49.0000.1921.6821.7002.00 0 msec ! 0 msec ! 0 msec !