IPv6 - Policy-based routing

Same topology as before but without the offset:

Three loopbacks on BB2 advertised through RIPng to R3:

2001:205:90:31::1
2001:220:20:3::1
2001:222:22:2::1

Here is a traceroute from VLAN38:

R3#trace
Protocol [ip]: ipv6
Target IPv6 address: 2001:205:90:31::1
Source address: FEC0:CC1E:1:38::3
Insert source routing header? [no]: no
Numeric display? [no]:
Timeout in seconds [3]:
Probe count [3]:
Minimum Time to Live [1]:
Maximum Time to Live [30]:
Priority [0]:
Port Number [33434]:
Type escape sequence to abort.
Tracing the route to 2001:205:90:31::1

1 FEC0:CC1E:1:35::5 28 msec 32 msec 32 msec
2 FEC0:CC1E:1:54::4 12 msec
FEC0:CC1E:1:45::4 60 msec
FEC0:CC1E:1:54::4 28 msec
3 2001:205:90:31::1 52 msec 72 msec 24 msec
R3#

Notice at step 2 of the trace we flip-flop between the two hops from R5. Let's use policy based routing to force traffic from VLAN38 to use the serial link to R4. On R5:

ipv6 access-list PBRv6
permit ipv6 FEC0:CC1E:1:38::/64 2001:205:90:31::/64
permit ipv6 FEC0:CC1E:1:38::/64 2001:220:20:3::/64
permit ipv6 FEC0:CC1E:1:38::/64 2001:222:22:2::/64

route-map PBRv6 permit 10
match ipv6 address PBRv6
set ipv6 default next-hop FEC0:CC1E:1:45::4

int s1/0.35
ipv6 policy route-map PBRv6

Do the trace again:

R3#trace
Protocol [ip]: ipv6
Target IPv6 address: 2001:205:90:31::1
Source address: FEC0:CC1E:1:38::3
Insert source routing header? [no]:
Numeric display? [no]:
Timeout in seconds [3]:
Probe count [3]:
Minimum Time to Live [1]:
Maximum Time to Live [30]:
Priority [0]:
Port Number [33434]:
Type escape sequence to abort.
Tracing the route to 2001:205:90:31::1

1 FEC0:CC1E:1:35::5 20 msec 36 msec 24 msec
2 FEC0:CC1E:1:45::4 4 msec 80 msec 24 msec
3 2001:205:90:31::1 16 msec 40 msec 36 msec
R3#

Sweet. What if the link between R4 and R5 fails?

R5(config-subif)#int s1/1
R5(config-if)#shut

Now back to R3:

Protocol [ip]: ipv6
Target IPv6 address: 2001:205:90:31::1
Source address: FEC0:CC1E:1:38::3
Insert source routing header? [no]:
Numeric display? [no]:
Timeout in seconds [3]:
Probe count [3]:
Minimum Time to Live [1]:
Maximum Time to Live [30]:
Priority [0]:
Port Number [33434]:
Type escape sequence to abort.
Tracing the route to 2001:205:90:31::1

1 FEC0:CC1E:1:35::5 48 msec 28 msec 44 msec
2 FEC0:CC1E:1:54::4 24 msec 88 msec 20 msec
3 2001:205:90:31::1 8 msec 64 msec 44 msec
R3#

Now we are using the frame relay link.