EIGRP for IPv6
This document describes how to configure Enhanced Interior Gateway Routing Protocol (EIGRP) for IPv6. EIGRP is an enhanced version of the IGRP developed by Cisco.
It is the
enhanced distance vector protocol, which relies on a diffused update algorithm
to determine the shortest path to the destination within the network. The EIGRP
for IP version 6 will work on the same way as EIGRP IP version 4, where it can
configure and managed separately.
The EIGRP is inherently the multicast routing protocol because it will
support for the non IP protocols. The mechanisms and configuration techniques
will slightly vary from the IPv4 to IPv6. The engineers or professionals who
have worked with the IPv4 will able to get the IPv6 concept very easily. The
EIGRP maintains the feature parity over the protocols, when appropriate.
Because of this difference, the operation and configuration will slightly
differ.
There are few major differences between the version 4 and version 6 are
such as:
·
The EIGRP for IPv6 routing process will use the shut down feature
·
With the EIGRP for IPv6, the router ID is needed on the each router or a
routing process will not start.
·
The EIGRP for the IPv6 is configured directly on a router interface.
To address certain issues in the IGRP, the Cisco created an enhanced
version of the EIGRP which is significantly more capable than the IGRP. To
advertise the routing information whenever necessary, there is the change
without the need of router to advertise that periodically, the layer 3
independent, transparent protocol is capable of the reliable multicast and
unicast delivery. To maintain the loop free operation at each instant, the
EIGRP uses the feasibility condition to identify the neighbors, offering the
guaranteed loop free path to the given destination. It will allow the EIGRP
router to avoid the forwarding packets to the neighbor from the routing loop.
To handle the multiple topology changes at the time of single diffusing
computation, the EIGRP implements the finite state machine is called as the
diffusing update algorithm which control diffusing computation run, inserting
the collected information and processing the reply into a routing table or just
connecting the additional diffusing computation.
The Internet protocol version6 packet is disabled by default. To enable
the IPv6 packet forwarding, it is important to use the command of ipv6 unicast-
routing in the global configuration before enabling the EIGRP. The router ID is
the mandatory one for the IPv6 EIGRP to function properly. Suppose, 1 is not
configured manually, one will be generated with the help of the physical
interface or loopback. Unlike the EIGRP for IPv4, IPv6 may not require the use
of the command network to advertise the network. This command has to be
configured on all the router interface which are participating in the EIGRP. If
you fail to configure that command on the interface, the network cannot
advertise, so, cannot be learned by its neighbor. While EIGRP for IPv6 is
configured on the entire interfaces, the log messages will inform that an
adjacency is formed.
You can use a command of passive interface to control the routing
information advertisement. This command enables the suppression of the routing
updates through some of the interfaces when it allows updates to be exchanged
over the other interfaces. When it is used with the EIGRP, it will suppress the
hello packet exchange between the routers that will result in a loss of the
neighbor relationship. Hence, it is used in the interfaces only where no
routers are connected with it. It will stop not only the routing updates in
advertising, but also suppresses the incoming routing updates.
To configure the EIGRP for IPv6, it is essential to have the knowledge
about EIGRP IPv6 and IPv6 addressing. Configuring the EIGRO for IPv6 has few
restrictions too. The interfaces may be directly configured with the EIGRP for
IPv6, without any use of the global IPv6 addresses. There is no network
statement in the EIGRP for the IPv6. The EIGRP for IPv6 has the shutdown
feature which ensures that the process of routing is in mode - no shut to start
running the protocol. The router ID requires to be configured for the EIGRP
IPv6 protocol instance before it can run.
Build a network and check the connectivity:
Set up the network topology and just configure the basic settings such
as device access, passwords and an interface IP addresses.
1.
Cable a network as shown in the above network topology
2.
Configure the PC host
3.
Initialize and also reload the routers as required
4.
Configure settings for the each router
5.
Disable the DNS lookup
6.
Configure the routers IP addresses as pointed in the addressing table.
In this case, configure FE80::x link local address as well as the unicast
address for every router interface.
7.
Configure a device name as given in a topology
8.
Assign the Cisco as vty and console passwords.
9.
Assign the class as a privileged EXEC password
10.
Configure the logging synchronous to prevent the vty and console
messages from the interrupting command entry.
11.
Configure the message of a day
12.
Copy a running configuration to startup the configuration.
13.
Verify the connectivity
The routers must able to ping one another and every PC must be able to
ping their default gateway. The PC cannot able to ping the other PC until the
EIGRP routing is configured. Then verify and troubleshoot if required.
Configure the EIGRP for the IPv6 routing:
1. Enable the IPv6 routing on a router
R1(config)#ipv6 router eigrp 1
2. Assign the router ID of the each router
To start an EIGRP for IPv6 routing configuration process, provide
command as ipv6 router eigrp 1, where AS number is denoted as 1.
The EIGRP for the IPv6 needs the 32 bit address for a router ID. Then
use the command router id to configure a router ID in a router configuration
mode.
3. Enable the EIGRP for IPv6 routing on every router
An IPv6 routing process is the shutdown as default. Then provide command
of no shutdown to enable the EIGRP for IP version 6 routing on entire router.
4. Configure the EIGRP for IPv6 by using the AS 1 on a gigabit Ethernet
and serial interfaces on a router.
Provide a command of ipv6 eigrp 1 on an interface which participate in
an EIGRP routing process. An AS number as 1 will assigned in the step 2. The R!
configuration is as follows:
Assign the EIGRP participating interface on r3 and R2. You can find the
neighbor adjacency messages as an interface is added to a routing process of
EIGRP. Given below is the R1 messages.
Verify the end to end connectivity
Verify the EIGRP for IPv6 routing:
1. Determine a neighbor adjacency
On the R1, provide the command show ipv6 eigrp neighbors to verify that
an adjacency has been accomplished with their neighboring routers. Then the
link local address of a neighbor router displayed in an adjacency table as
follows:
2. Examine an EIGRP IPv6 routing table
Use the command show ipv6 route eigrp to demonstrate the IPv6 certain
EIGRP routes on the whole routers.
3. Examine an EIGRP topology
The example as shown below:
R1# show ipv6 eigrp topology
4 . Verify current state and parameters of an active IPv6 process of
routing protocol
Provide the command show ipv6 protocols to verify a configured
parameter. In the output, the EIGRP is a configured IPv6 routing protocol along
with 1.1.1.1 as a router ID for the R!. The routing protocol is also associated
with an autonomous system1 with 3 active interfaces such as S0/0/1, S0/0/0 and
G0/0.
Configure and also verify the passive interface:
The passive interface will not allow the incoming and outgoing routing
update over a configured interface. A command of passive interface causes a
router to stop receiving and sending the hello packets over the interface.
1 . Configure the interface G0/0 as the passive on R2 and R1
2 . Verify the configuration of the passive interface
Provide the command as show ipv6 protocols on the R1 and verify it G0/0
is configured as passive interface.
3 . Configure a G0/0 passive interface on the R3
If some of the interfaces are configured as the passive, then use a
command of passive interface default to configure the entire interface on a
router as passive. Then use the command no passive interface to allow the EIGRP
hello message in as well as out of a router interface.
Configure all the interfaces as the passive on R3 as follows:
After providing the command passive interface default, the R3 will no
longer take part in a routing process. To configure the serial type interface
below routing process is very important.
A neighbor relationship has been accomplished again with the R2 and R1.
Then verify it only G0/0 is configured as the passive.
There are several additional configuration available for the EIGRP for
IPv6. The EIGRP IPv6 as well as EIGRPv4 use the same configuration and concept
commands for the unequal and equal cost load balancing. Configuration setting
is made with the variance commands and maximum path in the EIGRP for IPv6
configuration mode. Remember that this setting has to configure separately for
the IPv4 and IPv6 on the dual stack routers when the same configuration command
is used. The EIGRP for IPv6 use the same parameters exactly, the interfaces
such as delay and bandwidth, that are used with the IPv4 to calculate a metric
for the each route. An IOS configuration command to set that parameter,
commands used in the interface configuration mode are same for the IPv4 and
IPv6.
The EIGRP for IPv6 uses a same concept for the hold timers and hello as
like EIGRP ipv4. The command is used to set that parameters have to be used in
the global configuration mode. To set the parameter separately for the IPv6 and
IPv4, the IOS uses an IPv6 keyword for the EIGRP IPv6 command and an ip keyword
for an EIGRPv4 command.
Once the 2 EIGRPv6 routers become the neighbors, it will exchange all
the appropriate network topology information. The EIGRPv6 uses the bandwidth,
reliability, load and delay as the metric components like the EIGRPv4. A metric
calculation formula which is used by the EIGRPv6 is identical to the EIGRPv4.
The best path to the network is called as the successor route to the EIGRPv4
and the EIGRPv6 retains the concept. The feasible successor is the route which
mets a feasibility condition and potentially will become a successor path
suppose the route of the successor fails. The IPv4 and IPv6 of EIGRP both have
a feasible successor concept. The feasibility condition will dictate that a
reported distance is better than the current metric to reach a same subnet.
For the destination, all neighbors which pass the feasibility condition
and are safe to use as the next hops is known as feasible successors. The
feasible successor is the neighbor, which guaranteed to give the loop free
route to the destination and FS are identified by passing the feasibility
condition. Technically, each successor is the feasible successor because that
meets FC. Commonly, the feasible successor is used to indicate only the
neighbors which give the loop free. All feasible successors and successors to
the destination can get in an output of show ip eigrp topology. The poison
reverse and split horizon are used to prevent the routing loops in the EIGRP
for IPv6.
The EIGRP for IPv6 is the distance vector routing protocol with the same
link state features. It can be configured directly with the router interfaces
also. The EIGRPv6 will exchange the messages allowing a router to discover
neighbors, and from the neighbor relationship as well as advertises the subnets
along with a metric component for the every route. The EIGRPv6 has the same
successor as well as feasible successor concepts. From this section you can
learn how to configure and verify the EIGRP for IPv6. After the configuration,
it is very important to very the EIGRP for IPv6.
-===another example
http://www.cisco.com/c/en/us/support/docs/ip/enhanced-interior-gateway-routing-protocol-eigrp/113267-eigrp-ipv6-00.html
EIGRP IPv6 Configuration Example
Configuring EIGRP for IPv6 has some restrictions; they are listed below:
The interfaces can be directly configured with EIGRP for IPv6, without the use of a global IPv6 address. There is no network statement in EIGRP for IPv6.
The router ID needs to be configured for an EIGRPv6 protocol instance before it can run.
EIGRP for IPv6 has a shutdown feature. Ensure that the routing process is in "no shut" mode to start running the protocol.
The configurations in this document are based on the Cisco 3700 series router on Cisco IOS Software Release 12.4 (15)T 13.
In this example, two routers (R1 and R2) are configured with IPv6 address. Loopback addresses are assigned in both routers, and they are configured to be in EIGRP1. The EIGRPv6 is enabled per interface level using this command:
ipv6 eigrp as-number
This example uses this network setup:
This example uses these configuration:
| R1 Configuration |
|---|
hostname R1
!
ipv6 unicast-routing
!
interface Loopback0
no ip address
ipv6 address 1010:AB8::/64 eui-64
ipv6 enable
ipv6 eigrp 1
!
interface Loopback1
no ip address
ipv6 address 2020:AB8::/64 eui-64
ipv6 enable
ipv6 eigrp 1
!
interface Loopback2
no ip address
ipv6 address 3030:AB8::/64 eui-64
ipv6 enable
ipv6 eigrp 1
!
interface Serial0/0
no ip address
ipv6 address FE80::1 link-local
ipv6 address 2010:AB8::1/64
ipv6 enable
ipv6 eigrp 1
clock rate 2000000
!
ipv6 router eigrp 1
router-id 2.2.2.2
no shutdown
!
end
|
| R2 Configuration |
|---|
hostname R2
!
ipv6 unicast-routing
!
interface Loopback0
no ip address
ipv6 address 1000:AB8::/64 eui-64
ipv6 enable
ipv6 eigrp 1
!
interface Loopback1
no ip address
ipv6 address 2000:AB8::/64 eui-64
ipv6 enable
ipv6 eigrp 1
!
interface Loopback2
no ip address
ipv6 address 3000:AB8::/64 eui-64
ipv6 enable
ipv6 eigrp 1
!
interface Serial0/0
no ip address
ipv6 address FE80::2 link-local
ipv6 address 2010:AB8::2/64
ipv6 enable
ipv6 eigrp 1
clock rate 2000000
!
ipv6 router eigrp 1
router-id 1.1.1.1
no shutdown
!
end
|
Use this section to confirm that your configuration works properly.
| Show ipv6 eigrp neighbors |
|---|
Router R1
IPv6-EIGRP neighbors for process 1
H Address Interface Hold Uptime SRTT RTO Q Seq
(sec) (ms) Cnt Num
0 Link-local address: Se0/0 13 15:17:58 44 264 0 12
FE80::2
!--- Shows the link local address of router R2.
Router R2
IPv6-EIGRP neighbors for process 1
H Address Interface Hold Uptime SRTT RTO Q Seq
(sec) (ms) Cnt Num
0 Link-local address: Se0/0 14 16:32:05 30 300 0 12
FE80::1
!--- Shows the link local address of router R1.
|
The
show ipv6 route eigrp command shows the content of the IPv6 routing table that includes the routes specific to EIGRP.
| show ipv6 route eigrp |
|---|
Router R1
R1#show ipv6 route eigrp
IPv6 Routing Table - 12 entries
Codes: C - Connected, L - Local, S - Static, R - RIP, B - BGP
U - Per-user Static route, M - MIPv6
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
D - EIGRP, EX - EIGRP external
D 1000:AB8::/64 [90/2297856]
via FE80::2, Serial0/0
D 2000:AB8::/64 [90/2297856]
via FE80::2, Serial0/0
D 3000:AB8::/64 [90/2297856]
via FE80::2, Serial0/0
!--- This command shows IPv6-specific EIGRP routes.
Router R2
R2#show ipv6 route eigrp
IPv6 Routing Table - 12 entries
Codes: C - Connected, L - Local, S - Static, R - RIP, B - BGP
U - Per-user Static route, M - MIPv6
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
D - EIGRP, EX - EIGRP external
D 1010:AB8::/64 [90/2297856]
via FE80::1, Serial0/0
D 2020:AB8::/64 [90/2297856]
via FE80::1, Serial0/0
D 3030:AB8::/64 [90/2297856]
via FE80::1, Serial0/0
|
| show ipv6 eigrp interfaces |
|---|
Router R1
R1#show ipv6 eigrp 1 interface
IPv6-EIGRP interfaces for process 1
Xmit Queue Mean Pacing Time Multicast Pending
Interface Peers Un/Reliable SRTT Un/Reliable Flow Timer Routes
Se0/0 1 0/0 44 0/15 199 0
Lo0 0 0/0 0 0/1 0 0
Lo1 0 0/0 0 0/1 0 0
Lo2 0 0/0 0 0/1 0 0
!--- This command determines which interface EIGRP is active.
Router R2
R2#show ipv6 eigrp 1 interface
IPv6-EIGRP interfaces for process 1
Xmit Queue Mean Pacing Time Multicast Pending
Interface Peers Un/Reliable SRTT Un/Reliable Flow Timer Routes
Se0/0 1 0/0 30 0/15 135 0
Lo0 0 0/0 0 0/1 0 0
Lo1 0 0/0 0 0/1 0 0
Lo2 0 0/0 0 0/1 0 0
|
