EIGRP Named Mode or Multi-AF Mode is a new development in EIGRP starting in Version 15.x
Its reason for being is to simplify the EIGRP configuration into one place, as previously with EIGRP classic version the configuration was between the interface and the global process which made it harder to see all the configuration relating to EIGRP together.
In the back end nothing has changed so you can run EIGRP between to neighbors with one running classic mode and the other running named mode without a problem.
Using the simple topololgy below we will explore the basic setup and also look at authentication and eigrp named mode redistribution configuration.
First lets configure basic connectivity between R1 & R2
ip address 10.0.21.1 255.255.255.252
ip add 220.127.116.11 255.255.255.255
ip address 10.0.21.2 255.255.255.252
ip add 18.104.22.168 255.255.255.255
Before configuring EIGRP verify connectivity between R1 & R2
R1#ping 10.0.21.2 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 10.0.21.2, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 120/148/176 ms
Now we have verified connectivity lets step right into EIGRP Named Mode configuration.
With EIGRP classic mode you typed router eigrp and then picked a number for the AS Number – with named mode you have two options and the second is a word.
Choose a word and hit enter, you then have to configure the address-family and autonomous-system number. The EIGRP name can be locally significant but the
AS number has to match between routers as in classic mode.
R1(config)#router eigrp ROGER R1(config-router)#address-family ipv4 unicast autonomous-system 12
Now lets view the EIGRP named mode configuration
R1#sh run | sec router eigrp router eigrp ROGER ! address-family ipv4 unicast autonomous-system 12 ! topology base exit-af-topology exit-address-family R1#
At this point no interfaces have been enabled for EIGRP so no neighbors are coming up. We need to go back into the named configuration and add a network statement.
R1(config)#router eigrp ROGER R1(config-router)#address-family ipv4 unicast autonomous-system 12 R1(config-router-af)#network 10.0.21.1 0.0.0.0 R1(config-router-af)#network 22.214.171.124 0.0.0.0 R1(config-router-af)#end *Feb 9 21:57:21.375: %DUAL-5-NBRCHANGE: EIGRP-IPv4 12: Neighbor 10.0.21.2 (FastEthernet0/0) is up: new adjacency
I have already configured R2 so you can see the EIGRP neighbor comes up.
To verify connectivity to the loopback of R2 – lets ping 126.96.36.199
R1#ping 188.8.131.52 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 184.108.40.206, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 92/125/156 ms
You may be wondering what is the difference between Named Mode and Multi-AF Mode – the short answer is nothing. They are the same thing, even though the CCIE V5 Blueprint lists them as two separate items to learn which does provide an element of confusion.
EIGRP Named Mode Redistribution
Now lets take a look at something which on the face of it looks quite simple but with eigrp named mode has become a bit more complicated and that is redistribution.
First lets expand our topology to include another router running OSPF.
R3 has its loopback 220.127.116.11 in OSPF and we will be redistributing OSPF into EIGRP on R2
The first question is where under the new EIGRP configuration do you do the redistribution? Lets find out.
Go into the eigrp named mode, specify the address family and it is under topology base
R2#conf t Enter configuration commands, one per line. End with CNTL/Z. R2(config)#router eigrp ROG R2(config-router)#address-family ipv4 unicast autonomous-system 12 R2(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 R2(config-router-af)#topology base R2(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 fast-reroute Configure Fast-Reroute 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 R2(config-router-af-topology)#redistribute ospf 1 metric 1 1 1 1 1
Remember when redistributing into EIGRP you have to specify a metric. I have just chosen all ones here but as you will see this is going to cause problems.
Lets see if we now have the prefix 18.104.22.168/32 in the routing table of R1
R1#sh ip route 22.214.171.124 % Network not in table R1#
So why is that?
Lets look to see if the prefix is in the topology database
R1#sh ip eigrp topology 126.96.36.199/32 EIGRP-IPv4 VR(ROGER) Topology Entry for AS(12)/ID(188.8.131.52) for 184.108.40.206/32 State is Passive, Query origin flag is 1, 0 Successor(s), FD is Infinity, RIB is 4294967295 Descriptor Blocks: 10.0.21.2 (FastEthernet0/0), from 10.0.21.2, Send flag is 0x0 Composite metric is (655361310720/655360655360), route is External Vector metric: Minimum bandwidth is 1 Kbit Total delay is 20000000 picoseconds Reliability is 1/255 Load is 1/255 Minimum MTU is 1 Hop count is 1 Originating router is 220.127.116.11 External data: AS number of route is 12 External protocol is OSPF, external metric is 2 Administrator tag is 0 (0x00000000) EIGRP-IPv4 Topology Entry for AS(1)/ID(18.104.22.168) %Entry 22.214.171.124/32 not in topology table R1#
It is so why is not being installed into the routing table? Well with EIGRP named mode it uses a new feature called wide metrics, this is to overcome the limitations with the scaling of higher bandwidth links and to make the metrics more granular. However in our example our seed metric of 1 has caused an issue and if you look at the RIB metric above you will see it is 4294967295. The IOS RIB cannot only support a 32 bit number however the EIGRP wide metrics can now support a 64 bit number. The issue here is the Metric in the RIB is so high it cannot be installed into the routing table.
Lets change our seed metric to be a bit higher
R2(config-router-af-topology)#redistribute ospf 1 metric 10 10 255 1 1500
Checking on R1 again we can see this metric has now come within the limits and is installed into the routing table
R1#sh ip eigrp topology 126.96.36.199/32 EIGRP-IPv4 VR(ROGER) Topology Entry for AS(12)/ID(188.8.131.52) for 184.108.40.206/32 State is Passive, Query origin flag is 1, 1 Successor(s), FD is 65543208960, RIB is 512056320 Descriptor Blocks: 10.0.21.2 (FastEthernet0/0), from 10.0.21.2, Send flag is 0x0 Composite metric is (65543208960/65542553600), route is External R1#sh ip route 220.127.116.11 Routing entry for 18.104.22.168/32 Known via "eigrp 12", distance 170, metric 512056320, type external Redistributing via eigrp 12 Last update from 10.0.21.2 on FastEthernet0/0, 00:00:27 ago Routing Descriptor Blocks: * 10.0.21.2, from 10.0.21.2, 00:00:27 ago, via FastEthernet0/0 Route metric is 512056320, traffic share count is 1 Total delay is 110 microseconds, minimum bandwidth is 10 Kbit Reliability 255/255, minimum MTU 1500 bytes Loading 1/255, Hops 1
So when using EIGRP named mode you need to be careful of the higher metrics.
There is another feature in play and that is the metric rib-scale but default it is 128. This is a factor that EIGRP uses to scale down the metric and if we look at the example above you can see the composite metric is 65543208960 If we divide this by 128 you will get the metric used in the routing table.