Configuring IPv6 on Our Internetwork

I’ll configure the internetwork I’ve been using throughout this book—five routers connected together—but I’m not going to add IPv6 on the 871W router or to the LAN and WLAN networks connected to the R1, R2, and R3 routers, to keep things simple and easier to understand. So let’s get started by adding IPv6 to the Corp, R1, R2, and R3 routers. I’ll then add both the RIP and OSPF routing protocols and finish the chapter by running through some verification commands.

As usual, I’ll start with the Corp router:

Corp#config t
Corp(config)#ipv6 unicast-routing
Corp(config)#int f0/1
Corp(config-if)#ipv6 address 2001:db8:3c4d:11::/64 eui-64
Corp(config-if)#int s0/0/0
Corp(config-if)#ipv6 address 2001:db8:3c4d:12::/64 eui-64
Corp(config-if)#int s0/0/1
Corp(config-if)#ipv6 address 2001:db8:3c4d:13::/64 eui-64
Corp(config-if)#int s0/1/0
Corp(config-if)#ipv6 address 2001:db8:3c4d:14::/64 eui-64
Corp(config-if)#int s0/2/0
Corp(config-if)#ipv6 address 2001:db8:3c4d:15::/64 eui-64
Corp(config-if)#^Z
Corp#copy run start
Destination filename [startup-config]?[enter]
Building configuration...
[OK]
Corp#

In the preceding configuration, I changed the subnet address for each interface only slightly.
Let’s take a look at the routing table:

 Corp#sh ipv6 route
IPv6 Routing Table - 12 entries
Codes: C - Connected, L - Local, S - Static, R - RIP, B - BGP
U - Per-user Static route I1 - ISIS L1, I2 - ISIS L2, IA - ISIS
interarea, IS - ISIS summary O - OSPF intra, OI - OSPF inter,
OE1 - OSPF ext 1, OE2 - OSPF ext 2
ON1 - OSPF NSSA ext 1, ON2 - OSPF NSSA ext 2
C 2001:DB8:3C4D:11::/64 [0/0]
via ::, FastEthernet0/1
L 2001:DB8:3C4D:11:21A:2FFF:FE55:C9E9/128 [0/0]
via ::, FastEthernet0/1
C 2001:DB8:3C4D:12::/64 [0/0]
via ::, Serial0/0/0
L 2001:DB8:3C4D:12:21A:2FFF:FE55:C9E8/128 [0/0]
via ::, Serial0/0/0
C 2001:DB8:3C4D:13::/64 [0/0]
via ::, Serial0/0/1
L 2001:DB8:3C4D:13:21A:2FFF:FE55:C9E8/128 [0/0]
via ::, Serial0/0/1
C 2001:DB8:3C4D:14::/64 [0/0]
via ::, Serial0/1/0
L 2001:DB8:3C4D:14:21A:2FFF:FE55:C9E8/128 [0/0]
via ::, Serial0/1/0
C 2001:DB8:3C4D:15::/64 [0/0]
via ::, Serial0/2/0
L 2001:DB8:3C4D:15:21A:2FFF:FE55:C9E8/128 [0/0]
via ::, Serial0/2/0
L FE80::/10 [0/0]
via ::, Null0
L FF00::/8 [0/0]
via ::, Null0
Corp#

So what’s up with the two addresses for each interface? One shows C connected, and one shows L? Well, the connected address is the IPv6 address I configured on each interface, and the L is the automatically assigned link-local. Notice in the link-local address that the FF:FE is inserted into the address to create the eui-64 address.

One more thing before we move on to the R1 router. Notice that when addressing the interfaces, I added a different number to the subnet number for each one. Also note that they closely match my IPv4 private addresses. I did it this way to make administration easier. Okay—let’s configure the R1 router now:

R1#config t
R1(config)#ipv6 unicast-routing
R1(config)#int s0/0/0
R1(config-if)#ipv6 address 2001:db8:3c4d:12::/64 eui-64
R1(config-if)#int s0/0/1
R1(config-if)#ipv6 address 2001:db8:3c4d:13::/64 eui-64
R1(config-if)#^Z
R1#show ipv6 route
IPv6 Routing Table - 6 entries
[codes cut]
C 2001:DB8:3C4D:12::/64 [0/0]
via ::, Serial0/0/0
L 2001:DB8:3C4D:12:21A:6DFF:FE64:9B2/128 [0/0]
via ::, Serial0/0/0
C 2001:DB8:3C4D:13::/64 [0/0]
via ::, Serial0/0/1
L 2001:DB8:3C4D:13:21A:6DFF:FE64:9B2/128 [0/0]
via ::, Serial0/0/1
L FE80::/10 [0/0]
via ::, Null0
L FF00::/8 [0/0]
via ::, Null0
R1#

Notice that I used the exact same IPv6 subnet addresses on each side of the link. Let’s
configure the R2 and R3 routers, and then add RIPv6:

R2#config t
R2(config)#ipv6 unicast-routing
R2(config)#int s0/2/0
R2(config-if)#ipv6 address 2001:db8:3c4d:14::/64 eui-64
R2(config-if)#do show ipv6 route
IPv6 Routing Table - 4 entries

C 2001:DB8:3C4D:14::/64 [0/0]
via ::, Serial0/2/0
L 2001:DB8:3C4D:14:213:60FF:FE20:4E4C/128 [0/0]
via ::, Serial0/2/0
L FE80::/10 [0/0]
via ::, Null0
L FF00::/8 [0/0]
via ::, Null0
R2(config-if)#
Looking good! Let’s go to R3:
R3#config t
R3(config)#ipv6 unicast-routing
R3(config)#int s0/0/1
R3(config-if)#ipv6 address 2001:db8:3c4d:15::/64 eui-64
R3(config-if)#do show ipv6 route
IPv6 Routing Table - 4 entries
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(config-if)#

Again, notice that I used the exact same IPv6 subnet addresses on each side of the links from the Corp router to the R1, R2, and R3 routers. Now let’s start adding routing protocols!