In this article, we will discuss EIGRP named mode. If you are studying for CCNP, then you will run into this at some point.
There are two ways of configuring EIGRP. The classic way, called EIGRP AS mode, is the most common. Using this mode, commands related to EIGRP are placed in different hierarchies of the router configuration. For instance, the EIGRP hello and holdtime intervals are placed under interfaces whose subnet is advertised in EIGRP. The networks advertised in EIGRP are placed under EIGRP router configuration, but it’s not that easy to follow up an EIGRP configuration. You need to jump back and forth through the configuration to get all the pieces.
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The second method of configuring EIGRP is called named EIGRP. It was developed to consolidate the hierarchy where the entire EIGRP configuration is done. Basically, you have only one place where you need to look to check the configuration.
Named EIGRP is more about how to configure EIGRP. Nothing has changed in the operation of the protocol. But a few examples should clarify this.
We will use this topology:
This is how you enter the named EIGRP configuration:
R1(config)#router eigrp ? Autonomous System WORD EIGRP Virtual-Instance Name R1(config)#router eigrp
As you can see, it’s pretty similar to the old way of configuring EIGRP. Once you provide a name, then the device knows that you want to use named EIGRP.
R1(config)#router eigrp NAMED_EIGRP R1(config-router)#? Router configuration commands: address-family Enter Address Family command mode default Set a command to its defaults exit Exit from routing protocol configuration mode no Negate a command or set its defaults service-family Enter Service Family command mode shutdown Shutdown this instance of EIGRP R1(config-router)#
Once you enter the named EIGRP configuration hierarchy, you will not see too many options. However, the one that’s most interesting is “address-family”. From here you can select whether you’ll use EIGRP for IPv4 or IPv6:
R1(config-router)#address-family ? ipv4 Address family IPv4 ipv6 Address family IPv6
Going even further, you have the options to configure multiple families for IPv4, like unicast or multicast. You can enter the VRF where EIGRP will run if you want to as well. We will see this later:
R1(config-router)#address-family ipv4 ? autonomous-system Specify Address-Family Autonomous System Number multicast Address Family Multicast unicast Address Family Unicast vrf Specify a specific virtual routing/forwarding instance
Let’s be as specific as possible and select the unicast address family and configure our AS:
R1(config-router)#address-family ipv4 unicast autonomous-system 120
Once you enter the address-family hierarchy, you will see options that you would see under EIGRP routing protocol hierarchy in the old configuration format:
R1(config-router-af)#? Address Family configuration commands: af-interface Enter Address Family interface configuration default Set a command to its defaults eigrp EIGRP Address Family specific commands exit-address-family Exit Address Family configuration mode help Description of the interactive help system maximum-prefix Maximum number of prefixes acceptable in aggregate metric Modify metrics and parameters for address advertisement neighbor Specify an IPv4 neighbor router network Enable routing on an IP network no Negate a command or set its defaults shutdown Shutdown address family timers Adjust peering based timers topology Topology configuration mode
There are a few interesting commands in the above output that we will discuss in a few moments. One of them is “af-interface”. Here you configure interface EIGRP specific parameters:
R1(config-router-af-interface)#? Address Family Interfaces configuration commands: authentication authentication subcommands bandwidth-percent Set percentage of bandwidth percentage limit bfd Enable Bidirectional Forwarding Detection dampening-change Percent interface metric must change to cause update dampening-interval Time in seconds to check interface metrics default Set a command to its defaults exit-af-interface Exit from Address Family Interface configuration mode hello-interval Configures hello interval hold-time Configures hold time next-hop-self Configures EIGRP next-hop-self no Negate a command or set its defaults passive-interface Suppress address updates on an interface shutdown Disable Address-Family on interface split-horizon Perform split horizon summary-address Perform address summarization R1(config-router-af-interface)#
Here you can configure the EIGRP authentication, like EIGRP intervals for instance. Let’s configure the authentication:
R1(config-router-af-interface)#authentication ? key-chain key-chain mode authentication mode R1(config-router-af-interface)#authentication key-chain EIGRP R1(config-router-af-interface)#authentication mode md5 R1(config-router-af-interface)#end R1#
Let’s configure the timers as well:
R1(config-router-af-interface)#hello-interval 3 R1(config-router-af-interface)#hold-time 9 R1(config-router-af)#end R1#
Let’s go back to “address-family” hierarchy and configure EIGRP to run on the interface towards R2 by using the “network” command:
R1(config-router-af)#? Address Family configuration commands: af-interface Enter Address Family interface configuration default Set a command to its defaults eigrp EIGRP Address Family specific commands exit-address-family Exit Address Family configuration mode help Description of the interactive help system maximum-prefix Maximum number of prefixes acceptable in aggregate metric Modify metrics and parameters for address advertisement neighbor Specify an IPv4 neighbor router network Enable routing on an IP network no Negate a command or set its defaults shutdown Shutdown address family timers Adjust peering based timers topology Topology configuration mode R1(config-router-af)#network ? A.B.C.D Network number R1(config-router-af)#network 220.127.116.11 0.0.0.0 R1(config-router-af)#net 10.10.12.1 0.0.0.0 R1(config-router-af)#
After this, the EIGRP adjacency between R1 and R2 is up:
*May 22 06:34:54.503: %DUAL-5-NBRCHANGE: EIGRP-IPv4 120: Neighbor 10.10.12.2 (FastEthernet0/0) is up: new adjacency
One other interesting command under “address-family” hierarchy is “topology”. From here you can configure specific EIGRP parameters like default route origination, K values and load balancing:
R1(config-router-af-topology)#? Address Family Topology configuration commands: auto-summary Enable automatic network number summarization default Set a command to its defaults default-information Control distribution of default information default-metric Set metric of redistributed routes distance Define an administrative distance distribute-list Filter entries in eigrp updates eigrp EIGRP specific commands exit-af-topology Exit from Address Family Topology configuration mode maximum-paths Forward packets over multiple paths metric Modify metrics and parameters for advertisement no Negate a command or set its defaults offset-list Add or subtract offset from EIGRP metrics redistribute Redistribute IPv4 routes from another routing protocol snmp Modify snmp parameters summary-metric Specify summary to apply metric/filtering timers Adjust topology specific timers traffic-share How to compute traffic share over alternate paths variance Control load balancing variance R1(config-router-af-topology)#
We will change the parameters that define on how many paths EIGRP can do load-balancing using the “maximum-paths” command. I did the same on R2:
R1(config-router-af-topology)#maximum-paths ? Number of paths R1(config-router-af-topology)#maximum-paths 16 R1(config-router-af-topology)#
Now, let’s compare the configuration from R1, which uses named EIGRP, with the one from R2, which uses the old way of configuring EIGRP. This is from R1:
router eigrp NAMED_EIGRP ! address-family ipv4 unicast autonomous-system 120 ! af-interface FastEthernet0/0 authentication mode md5 authentication key-chain EIGRP hello-interval 3 hold-time 9 exit-af-interface ! topology base maximum-paths 16 exit-af-topology network 18.104.22.168 0.0.0.0 network 10.10.12.1 0.0.0.0 exit-address-family !
And this is from R2. As you can see, the equivalent configuration is spread among different configuration hierarchies:
interface FastEthernet0/0 ip address 10.10.12.2 255.255.255.0 ip hello-interval eigrp 120 3 ip hold-time eigrp 120 9 ip authentication mode eigrp 120 md5 ip authentication key-chain eigrp 120 EIGRP duplex auto speed auto ! router eigrp 120 network 22.214.171.124 0.0.0.0 network 10.10.12.2 0.0.0.0 maximum-paths 16 no auto-summary !
And the EIGRP routes are in R1’s routing table:
R1#show ip route eigrp | b Gateway Gateway of last resort is not set 126.96.36.199/32 is subnetted, 2 subnets D 188.8.131.52 [90/2662400] via 10.10.12.2, 00:41:38, FastEthernet0/0 R1#
And this was the configuration of EIGRP for IPv4 between R1 and R2.
Now we will configure EIGRP for IPv6 between R1 and R3. On the interfaces between them, IPv6 addresses are configured and IPv6 routing is already enabled. These actions have nothing to do with EIGRP for IPv6 and they are prerequisites for a router to forward IPv6 traffic. Actually, we might not need to configure IPv6 addresses because EIGRP packets are sourced from the link-local IPv6 addresses that are automatically configured once you enable IPv6 on the interface using “IPv6 enable”. But to keep things consistent, we will configure IPv6 addresses.
The only thing that we need to do is to enable address-family for IPv6 under named EIGRP configuration:
R1(config)#router eigrp NAMED_EIGRP R1(config-router)#address-family ipv6 unicast autonomous-system 130 *May 22 08:54:15.183: %DUAL-5-NBRCHANGE: EIGRP-IPv6 130: Neighbor FE80::C804:D9FF:FE7D:0 (FastEthernet1/0) is up: new adjacency R1(config-router-af)#end R1#
So this would be the whole configuration on R1 regarding EIGRP for IPv6:
router eigrp NAMED_EIGRP ! address-family ipv6 unicast autonomous-system 130 ! topology base exit-af-topology exit-address-family !
Whereas the configuration on R3 involves enabling EIGRP for IPv6 under the interface that should be part of the routing protocol:
interface Loopback0 ip address 184.108.40.206 255.255.255.255 ipv6 address 2001:1:1:1::3/128 ipv6 enable ipv6 eigrp 130 ! interface FastEthernet0/0 ip address 10.10.13.3 255.255.255.0 duplex half ipv6 address 2001:1:2:3::3/64 ipv6 enable ipv6 eigrp 130 ! ipv6 router eigrp 130 !
The routes are exchanged for IPv6 through EIGRP:
R1#show ipv route eigrp | b 2001 D 2001:1:1:1::3/128 [90/2662400] via FE80::C804:D9FF:FE7D:0, FastEthernet1/1 R1#
The last option in configuring EIGRP is to configure it in a VRF. Again, you will need to set up the right address-family. In out topology, R4 has already been configured using the old way of configuring EIGRP and it is not part of VRF.
On the other hand, on R1, the interface F1/1 is part of VRF VRF_140.
This is the configuration on R1:
router eigrp NAMED_EIGRP ! address-family ipv4 unicast vrf VRF_140 autonomous-system 140 ! topology base exit-af-topology network 220.127.116.11 0.0.0.0 network 10.10.14.1 0.0.0.0 exit-address-family !
As you can see, the configuration is almost identical to the one from the initial IPv4 address-family, except now the routes will be placed in a VRF. There is a specific configuration that needs to be done to configure the VRF and to place the interfaces in the VRF:
vrf definition VRF_140 rd 140:140 ! address-family ipv4 exit-address-family ! interface FastEthernet1/1 vrf forwarding VRF_140 ip address 10.10.14.1 255.255.255.0 duplex auto speed auto !
Once this is configured, you can see that the EIGRP adjacency was established for the VRF and that the routes are placed in it:
R1#show ip eigrp vrf VRF_140 neighbors EIGRP-IPv4 VR(NAMED_EIGRP) Address-Family Neighbors for AS(140) VRF(VRF_140) H Address Interface Hold Uptime SRTT RTO Q Seq (sec) (ms) Cnt Num 0 10.10.14.4 Fa1/1 12 00:06:46 16 100 0 2 R1#show ip route vrf VRF_140 Routing Table: VRF_140 Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGP D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2 E1 - OSPF external type 1, E2 - OSPF external type 2 i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2 ia - IS-IS inter area, * - candidate default, U - per-user static route o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP + - replicated route, % - next hop override Gateway of last resort is not set 18.104.22.168/32 is subnetted, 1 subnets D 22.214.171.124 [90/2662400] via 10.10.14.4, 00:07:08, FastEthernet1/1 10.0.0.0/8 is variably subnetted, 2 subnets, 2 masks C 10.10.14.0/24 is directly connected, FastEthernet1/1 L 10.10.14.1/32 is directly connected, FastEthernet1/1 R1#
And that’s it about named EIGRP. By reaching this point of the article, you now will have a fair idea of what people talk about when they mention named EIGRP. Also, you now know how to configure EIGRP for IPv4, IPv6 and for VRF using the named EIGRP method.
- CCNP Routing and Switching Official Cert Guide – Kevin Wallace
- EIGRP Classic to Named Mode Conversion