IPv6 IS-IS FRR configuration example
Network requirements
As shown in Figure 117, Switch A, Switch B, and Switch C belong to the same IS-IS routing domain. Configure IPv6 IS-IS FRR so that when the Link A fails, traffic can be switched to Link B immediately.
Figure 117: Network diagram
Table 29: Interface and IP address assignment
Device | Interface | IP address | Device | Interface | IP address |
|---|---|---|---|---|---|
Switch A | Vlan-int100 | 1::1/64 | Switch B | Vlan-int101 | 3::1/64 |
Vlan-int200 | 2::1/64 | Vlan-int200 | 2::2/64 | ||
Loop0 | 10::1/128 | Loop0 | 20::1/128 | ||
Switch C | Vlan-int100 | 1::2/64 | |||
Vlan-int101 | 3::2/64 |
Configuration procedure
Configure IPv6 addresses for interfaces on the switches and enable IPv6 IS-IS. (Details not shown.)
Configure IPv6 IS-IS on the switches to make sure Switch A, Switch B, and Switch C can communicate with each other at Layer 3. (Details not shown.)
Configure IPv6 IS-IS FRR:
Enable IPv6 IS-IS FRR to calculate a backup next hop through LFA calculation, or designate a backup next hop by using a referenced routing policy.
(Method 1.) Enable IPv6 IS-IS FRR to calculate a backup next hop through LFA calculation:
# Configure Switch A.
<SwitchA> system-view [SwitchA] isis 1 [SwitchA-isis-1] address-family ipv6 [SwitchA-isis-1-ipv6] fast-reroute lfa
# Configure Switch B.
<SwitchB> system-view [SwitchB] isis 1 [SwitchB-isis-1] address-family ipv6 [SwitchB-isis-1-ipv6] fast-reroute lfa
(Method 2.) Enable IPv6 IS-IS FRR to designate a backup next hop by using a routing policy:
# Configure Switch A.
<SwitchA> system-view [SwitchA] ipv6 prefix-list abc index 10 permit 20::1 128 [SwitchA] route-policy frr permit node 10 [SwitchA-route-policy-frr-10] if-match ipv6 address prefix-list abc [SwitchA-route-policy-frr-10] apply ipv6 fast-reroute backup-interface vlan-interface 100 backup-nexthop 1::2 [SwitchA-route-policy-frr-10] quit [SwitchA] isis 1 [SwitchA-isis-1] address-family ipv6 [SwitchA-isis-1-ipv6] fast-reroute route-policy frr [SwitchA-isis-1-ipv6] quit [SwitchA-isis-1] quit
# Configure Switch B.
<SwitchB> system-view [SwitchB] ipv6 prefix-list abc index 10 permit 10::1 128 [SwitchB] route-policy frr permit node 10 [SwitchB-route-policy-frr-10] if-match ipv6 address prefix-list abc [SwitchB-route-policy-frr-10] apply ipv6 fast-reroute backup-interface vlan-interface 101 backup-nexthop 3::2 [SwitchB-route-policy-frr-10] quit [SwitchB] isis 1 [SwitchB-isis-1] address-family ipv6 [SwitchB-isis-1-ipv6] fast-reroute route-policy frr [SwitchB-isis-1-ipv6] quit [SwitchB-isis-1] quit
Verifying the configuration
# Display route 20::1/128 on Switch A to view the backup next hop information.
[SwitchA] display ipv6 routing-table 20::1 128 verbose
Summary count : 1
Destination: 20::1/128
Protocol: IS_L1
Process ID: 1
SubProtID: 0x1 Age: 00h27m45s
Cost: 10 Preference: 15
IpPre: N/A QosLocalID: N/A
Tag: 0 State: Active Adv
OrigTblID: 0xa OrigVrf: default-vrf
TableID: 0xa OrigAs: 0
NibID: 0x24000005 LastAs: 0
AttrID: 0xffffffff Neighbor: ::
Flags: 0x10041 OrigNextHop: FE80::34CD:9FF:FE2F:D02
Label: NULL RealNextHop: FE80::34CD:9FF:FE2F:D02
BkLabel: NULL BkNextHop: FE80::7685:45FF:FEAD:102
Tunnel ID: Invalid Interface: Vlan-interface200
BkTunnel ID: Invalid BkInterface: Vlan-interface100
FtnIndex: 0x0 TrafficIndex: N/A
Connector: N/A
# Display route 10::1/128 on Switch B to view the backup next hop information.
[SwitchB] display ipv6 routing-table 10::1 128 verbose
Summary count : 1
Destination: 10::1/128
Protocol: IS_L1
Process ID: 1
SubProtID: 0x1 Age: 00h33m23s
Cost: 10 Preference: 15
IpPre: N/A QosLocalID: N/A
Tag: 0 State: Active Adv
OrigTblID: 0xa OrigVrf: default-vrf
TableID: 0xa OrigAs: 0
NibID: 0x24000006 LastAs: 0
AttrID: 0xffffffff Neighbor: ::
Flags: 0x10041 OrigNextHop: FE80::34CC:E8FF:FE5B:C02
Label: NULL RealNextHop: FE80::34CC:E8FF:FE5B:C02
BkLabel: NULL BkNextHop: FE80::7685:45FF:FEAD:102
Tunnel ID: Invalid Interface: Vlan-interface200
BkTunnel ID: Invalid BkInterface: Vlan-interface101
FtnIndex: 0x0 TrafficIndex: N/A
Connector: N/A