Configuring RIPng

This is really the easy part—all I need to do is to go to each interface on each of our routers and type in one command. Here we go:

Corp#config t
Corp(config)#int f0/1
Corp(config-if)#ipv6 rip ?
WORD User selected string identifying this RIP process
Corp(config-if)#ipv6 rip 1 enable
Corp(config-if)#int s0/0/0
Corp(config-if)#ipv6 rip 1 enable
Corp(config-if)#int s0/0/1
Corp(config-if)#ipv6 rip 1 enable
Corp(config-if)#int s0/1/0
Corp(config-if)#ipv6 rip 1 enable
Corp(config-if)#int s0/2/0
Corp(config-if)#ipv6 rip 1 enable

Let’s configure the R1 router:

R1#config t
R1(config)#int s0/0/0
R1(config-if)#ipv6 rip 1 enable
R1(config-if)#int s0/0/1
R1(config-if)#ipv6 rip 1 enable

R2 config:

R2#config t
R2(config)#int s0/2/0
R2(config-if)#ipv6 rip 1 enable

R3 config:

R3#config t
R3(config)#int s0/0/1
R3(config-if)#ipv6 rip 1 enable

Okay, time to verify my IPv6 routing tables and configurations.

Verifying RIPng

I’m going to start with the usual show ip route command. Here’s the output from the R3 router:

R3#sh ipv6 route

R   2001:DB8:3C4D:11::/64 [120/2]
via FE80::21A:2FFF:FE55:C9E8, Serial0/0/1
R   2001:DB8:3C4D:12::/64 [120/2]
via FE80::21A:2FFF:FE55:C9E8, Serial0/0/1
R   2001:DB8:3C4D:13::/64 [120/2]
via FE80::21A:2FFF:FE55:C9E8, Serial0/0/1
R   2001:DB8:3C4D:14::/64 [120/2]
via FE80::21A:2FFF:FE55:C9E8, Serial0/0/1
C   2001:DB8:3C4D:15::/64 [0/0]
via ::, Serial0/0/1
L   2001:DB8:3C4D:15:21A:6DFF:FE37:A44E/128 [0/0]
 via ::, Serial0/0/1
L   FE80::/10 [0/0]
via ::, Null0
L   FF00::/8 [0/0]
via ::, Null0
R3#

Wow, looks just like the regular IPv4 RIP table, including the administrative distance and hop count. I can see subnets 11, 12, 13, 14, and 15.

Let’s take a look at a few more verification commands:

R3#sh ipv6 protocols
IPv6 Routing Protocol is “connected”
IPv6 Routing Protocol is “static”
IPv6 Routing Protocol is “rip 1”
Interfaces:
Serial0/0/1
Redistribution:
None
R3#

Not too much information provided with the show ipv6 protocols command. Let’s try the show ipv6 rip command:

R3#sh ipv6 rip
RIP process “1”, port 521, multicast-group FF02::9, pid 60
Administrative distance is 120. Maximum paths is 16
Updates every 30 seconds, expire after 180
Holddown lasts 0 seconds, garbage collect after 120
Split horizon is on; poison reverse is off
Default routes are not generated
Periodic updates 44, trigger updates 19
Interfaces:
Serial0/0/1
Redistribution:
None

Okay—now we’re talking! We can see that the administrative distance is still 120, plus the multicast group, maximum paths, and timers. So let’s go ahead and try two more verification commands, beginning with the show ipv6 interface s0/0/1 command:

R3#sh ipv6 interface serial 0/0/1
Serial0/0/1 is up, line protocol is up
IPv6 is enabled, link-local address is FE80::21A:6DFF:FE37:A44E
Global unicast address(es):
2001:DB8:3C4D:1:21A:6DFF:FE37:A44E, subnet is 2001:DB8:3C4D:1::/64 [EUI]
Joined group address(es):
FF02::1
FF02::2
FF02::9
FF02::1:FF37:A44E
MTU is 1500 bytes
ICMP error messages limited to one every 100 milliseconds
ICMP redirects are enabled
ND DAD is enabled, number of DAD attempts: 1
ND reachable time is 30000 milliseconds
Hosts use stateless autoconfig for addresses.

This got us some pretty good information too. But wait, the best is yet to come: the debug ipv6 rip command—this should be good:

R3#debug ipv6 rip

*May 24 18:31:11.959: RIPng: Sending multicast update on Serial0/0/1 for 1
*May 24 18:31:11.959: src=FE80::21A:6DFF:FE37:A44E
*May 24 18:31:11.959: dst=FF02::9 (Serial0/0/1)
*May 24 18:31:11.959: sport=521, dport=521, length=32
*May 24 18:31:11.959: command=2, version=1, mbz=0, #rte=1
*May 24 18:31:11.959: tag=0, metric=1, prefix=2001:DB8:3C4D:1::/64
*May 24 18:40:44.079: %LINEPROTO-5-UPDOWN: Line protocol on Interface
Serial0/0/0, changed state to down
*May 24 18:31:24.959: RIPng: response received from
FE80::21A:2FFF:FE55:C9E8 on Serial0/0/1 for 1
*May 24 18:31:24.959: src=FE80::21A:2FFF:FE55:C9E8 (Serial0/0/1)
*May 24 18:31:24.959: dst=FF02::9
*May 24 18:31:24.959: sport=521, dport=521, length=32
*May 24 18:31:24.959: command=2, version=1, mbz=0, #rte=1
*May 24 18:31:24.959: tag=0, metric=16,
prefix=2001:DB8:3C4D:12::/64
*May 24 18:31:24.959: RIPng: 2001:DB8:3C4D:12::/64, path
FE80::21A:2FFF:FE55:C9E8/Serial0/0/1 unreachable
*May 24 18:31:24.959: RIPng: 2001:DB8:3C4D:12::/64, expired, ttg is 120
*May 24 18:31:24.959: RIPng: Triggered update requested
*May 24 18:31:25.959: RIPng: generating triggered update for 1
*May 24 18:31:25.959: RIPng: Suppressed null multicast update on
Serial0/0/1 for 1

Now this is interesting. We can see that the source and destination ports used are 521 (yes, we are still using UDP) and that network/subnet 12 is unreachable. This is because the s0/0/0 interface of my Corp router has just decided to go bad. (I swear, writing this book is just like being at work!) Either way, we can see that RIPng still has some basic IPv4 RIP characteristics.