EIGRP for IPv6

Hi IPexpert blog followers,

Today is the day that I am going to teach you about another new topic for the CCIE R&S 4.0 Lab.  This time it’s EIGRP for IPv6 as you probably already figured out from the blog article title.

Well you probably all know EIGRP for IPv4 if not then google is your friend of just leave me us a message and I or one of my IPexpert colleagues would be more than happy to write a blog on that.

Well as the scope for this article is about EIGRP for IPv6 I will lay out a few facts about this routing protocol.

As we also may know EIGRP is the enhanced version of the IGRP developed by Cisco. EIGRP uses the same distance vector algorithm and distance information as IGRP. However, the convergence properties and the operating efficiency of EIGRP have improved substantially over IGRP.

Here are a few things you need to know before starting:

• EIGRP for IPv6 is configured under the interface just like OSPFv3 and RIPng and networks are also advertised using the interface command.
• When you configured this under the interface, IPv6 for EIGRP is always started in the so called in “shutdown” mode.
• Just like you probably know with OSPFv3, IPv6 EIGRP also requires a router-id in IPv4 format.
• When you want to configure passive interfaces these only can be configured under the routing process.
• Before you can start configuring EIGRP for IPv6 you probably need some extra memory resources and you need the IOS 12.4(6)T version or later.
• Unlike EIGRP for IPv4 it’s not possible to configure split horizon for EIGRP for IPv6 because it offers the possibility to create multiple prefixes per interface.
• There is no concept of classful routing within IPv6 for EIGRP and also it’s not possible to automatically summarize the networks.
• EIGRP for IPv6 provides route filtering using the distribute-list prefix-list command. The use of the route-map command is not supported for route filtering with a distribute list.

To show you how it’s working I’ve set up a dynamips/GNS3 topology for you guys so you can see how you do the configuration.

We will use the following diagram:

The first step is to assign the IP addresses to the interfaces we want to enable IPv6 for

After assigning  the IPv6 addresses we need to enable IPv6 on all the routers

ipv6 unicast-routing
ipv6 cef

The we need to create the EIGRPv6 router process and enable it on the interfaces

ipv6 router eigrp 100
no shutdown
!
interface FastEthernet0/0
ipv6 enable
ipv6 eigrp 100

The full configuration files  can be found below:

• R0
• R1
• R2
• R3

The .net file for building the mini lab using the above configs can be downloaded

ipv6_eigrp.

For this example I will only use R0 to do all the verification commands on.

If you’re interested how the other routers outputs will look like you can build the lab by yourself. I know I told you before you can build this lab but I also want to and I encourage you to do so, because nothing beats the hands-on self experience.

Show the routing table:

R0#sh ipv6 route
IPv6 Routing Table - Default - 5 entries
Codes: C - Connected, L - Local, S - Static, U - Per-user Static route
B - BGP, M - MIPv6, R - RIP, I1 - ISIS L1
I2 - ISIS L2, IA - ISIS interarea, IS - ISIS summary, D - EIGRP
EX - EIGRP external
O - OSPF Intra, OI - OSPF Inter, OE1 - OSPF ext 1, OE2 - OSPF ext 2
ON1 - OSPF NSSA ext 1, ON2 - OSPF NSSA ext 2
LC  2009:1000::/128 [0/0]
via Loopback0, receive
D   2009:1000::1/128 [90/156160] 
via FE80::C801:14FF:FED0:0, FastEthernet0/0
D   2009:1000::2/128 [90/156160] 
via FE80::C802:14FF:FED0:0, FastEthernet1/0
D   2009:1000::3/128 [90/156160] 
via FE80::C803:14FF:FED0:0, FastEthernet2/0
L   FF00::/8 [0/0]
via Null0, receive

Show the neighbours:

R0#sh ipv6 eigrp neighbors
IPv6-EIGRP neighbors for process 100
H   Address                 Interface       Hold Uptime   SRTT   RTO  Q  Seq
(sec)         (ms)       Cnt Num
2   Link-local address:     Fa2/0             14 01:23:27   45   405  0  13
FE80::C803:14FF:FED0:0
1   Link-local address:     Fa1/0             11 01:23:49  117   702  0  10
FE80::C802:14FF:FED0:0
0   Link-local address:     Fa0/0             13 01:24:10  895  5000  0  13
FE80::C801:14FF:FED0:0

Show the topology:

R0#sh ipv6 eigrp topology
IPv6-EIGRP Topology Table for AS(100)/ID(10.10.0.0)
Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply,
r - reply Status, s - sia Status
P 2009:1000::1/128, 1 successors, FD is 156160 
via FE80::C801:14FF:FED0:0 (156160/128256), FastEthernet0/0
P 2009:1000::/128, 1 successors, FD is 128256 
via Connected, Loopback0
P 2009:1000::3/128, 1 successors, FD is 156160 
via FE80::C803:14FF:FED0:0 (156160/128256), FastEthernet2/0
P 2009:1000::2/128, 1 successors, FD is 156160 
via FE80::C802:14FF:FED0:0 (156160/128256), FastEthernet1/0

Regards,

ing. Iwan Hoogendoorn

CCIE #13084 (R&S / Security / SP)

Sr. Support Engineer – IPexpert, Inc.

URL: http://www.IPexpert.com

Tags: CCIE R&S, EIGRP for IPv6, ipexpert