EIGRP Redistribution – Changing Metric and AD

This is using the same Topology setup as the RIP / OSPF Redistribution posts, however as noted in micro-text on the Topology below, I’ve changed the OSPF Area 0 to EIGRP AS 100, and removed any loopbacks in the EIGRP route domain as they are not necessary for now:

To change the metric or ‘seed metric’ in EIGRP, you have two options / commands:

• “default-metric 1544 10 255 1 1500” in router configuration mode for EIGRP, this changes all seed metrics to use the following values to calculate it, those numbers in order being Bandwidth, Delay, Reliability, BW Again, and MTU – This changes the default metric for all Redistributed routes into the EIGRP routing domain
  
• “redistribute rip metric …” to only change the metric for routes coming from a particular protocol, whereas “default-metric …” sets a seed for all protocols

Here is an example, step by step, of configuring Redistributing RIP into the EIGRP routing domain, with ?’s to see what about is required, and also how the routes change.

Here is R2’s routes to R1’s Loopbacks before Redistribution:

R2#show ip route rip
20.0.0.0/24 is subnetted, 1 subnets
R       20.1.1.0 [120/1] via 172.12.123.1, 00:00:04, Serial0/0
10.0.0.0/24 is subnetted, 1 subnets
R       10.1.1.0 [120/1] via 172.12.123.1, 00:00:04, Serial0/0
15.0.0.0/24 is subnetted, 1 subnets
R       15.1.1.0 [120/1] via 172.12.123.1, 00:00:04, Serial0/0

Now I will do Redistribution, and ? every step of the way to demonstrate the metrics needed to input, first time around we will define the protocol the metric is being set for:

R3(config)#router eigrp 100
R3(config-router)#redist rip ?
metric     Metric for redistributed routes
route-map  Route map reference
<cr>

R3(config-router)#redist rip metric ?
<1-4294967295>  Bandwidth metric in Kbits per second

R3(config-router)#redist rip metric 1544 ?
<0-4294967295>  EIGRP delay metric, in 10 microsecond units

R3(config-router)#redist rip metric 1544 10 ?
<0-255>  EIGRP reliability metric where 255 is 100% reliable

R3(config-router)#redist rip metric 1544 10 255 ?
<1-255>  EIGRP Effective bandwidth metric (Loading) where 255 is 100% loaded

R3(config-router)#redist rip metric 1544 10 255 1 ?
<1-65535>  EIGRP MTU of the path

R3(config-router)#redist rip metric 1544 10 255 1 1500 ?
route-map  Route map reference
<cr>

R3(config-router)#redist rip metric 1544 10 255 1 1500
R3(config-router)#

Now RIP Routes will be Redistributing into the EIGRP routing domain, however only the seed metric was adjusted so far, NOT the AD. Now to see if it affected R2’s routes:

R2#show ip route rip
20.0.0.0/24 is subnetted, 1 subnets
R       20.1.1.0 [120/1] via 172.12.123.1, 00:00:09, Serial0/0
10.0.0.0/24 is subnetted, 1 subnets
R       10.1.1.0 [120/1] via 172.12.123.1, 00:00:09, Serial0/0
15.0.0.0/24 is subnetted, 1 subnets
R       15.1.1.0 [120/1] via 172.12.123.1, 00:00:09, Serial0/0

Same thing, which should be happening, as RIP’s AD of 120 is lower than EIGRP External route AD of 170, but I want to confirm they are still known to R2 as backup routes so I tested this by shutting down the interface in the RIP routing domain:

R2(config)#int s0/0
R2(config-if)#shut
R2(config-if)#
*Mar  1 10:17:49.899: %LINK-5-CHANGED: Interface Serial0/0, changed state to administratively down
*Mar  1 10:17:50.901: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/0, changed state to down
R2(config-if)#do show ip route rip

R2(config-if)#do show ip route eigrp
20.0.0.0/24 is subnetted, 1 subnets
D EX    20.1.1.0 [170/1662976] via 30.1.1.3, 00:00:22, FastEthernet0/0
172.12.0.0/24 is subnetted, 1 subnets
D EX    172.12.123.0 [170/1662976] via 30.1.1.3, 00:00:22, FastEthernet0/0
10.0.0.0/24 is subnetted, 1 subnets
D EX    10.1.1.0 [170/1662976] via 30.1.1.3, 00:00:22, FastEthernet0/0
15.0.0.0/24 is subnetted, 1 subnets
D EX    15.1.1.0 [170/1662976] via 30.1.1.3, 00:00:22, FastEthernet0/0

And there are the EIGRP routes once that RIP interface drops.

Now I am going to try a different approach to setting the seed metric, using the “default-metric” command, then just doing “redistribute eigrp” on the ASBR to see how or if this changes the routes and metrics being passed to R2 (after removing old Redist commands):

R3(config-router)#no redist rip metric 1544 10 255 1 1500
R3(config-router)#default-metric 1544 10 255 1 1500
R3(config-router)#redist rip

Then go over to R2 to verify if any behaviors changed between the two methods:

R2#show ip route rip
20.0.0.0/24 is subnetted, 1 subnets
R       20.1.1.0 [120/1] via 172.12.123.1, 00:00:11, Serial0/0
10.0.0.0/24 is subnetted, 1 subnets
R       10.1.1.0 [120/1] via 172.12.123.1, 00:00:11, Serial0/0
15.0.0.0/24 is subnetted, 1 subnets
R       15.1.1.0 [120/1] via 172.12.123.1, 00:00:11, Serial0/0
R2#conf t
Enter configuration commands, one per line.  End with CNTL/Z.
R2(config)#int s0/0
R2(config-if)#shut
R2(config-if)#
*Mar  1 10:56:01.227: %LINK-5-CHANGED: Interface Serial0/0, changed state to administratively down
*Mar  1 10:56:02.229: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/0, changed state to down
R2(config-if)#do show ip route eigrp
20.0.0.0/24 is subnetted, 1 subnets
D EX    20.1.1.0 [170/1662976] via 30.1.1.3, 00:00:12, FastEthernet0/0
172.12.0.0/24 is subnetted, 1 subnets
D EX    172.12.123.0 [170/1662976] via 30.1.1.3, 00:00:12, FastEthernet0/0
10.0.0.0/24 is subnetted, 1 subnets
D EX    10.1.1.0 [170/1662976] via 30.1.1.3, 00:00:12, FastEthernet0/0
15.0.0.0/24 is subnetted, 1 subnets
D EX    15.1.1.0 [170/1662976] via 30.1.1.3, 00:00:12, FastEthernet0/0
R2(config-if)#

Nothing has changed at all, except that the default metric of EIGRP routes will be calculated from the values configured on “default-metric” – However I was wondering what would happen if I just did “redist rip” without any sort of metric changing? Here is what it looks like:

R3(config)#router eigrp 100
R3(config-router)#no redist rip
R3(config-router)#no default-metric 1544 10 255 1 1500
R3(config-router)#redist rip
R3(config-router)#
ASR#2
[Resuming connection 2 to r2 … ]

*Mar  1 11:10:18.673: %SYS-5-CONFIG_I: Configured from console by console
*Mar  1 11:10:19.402: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/0, changed state to up[OK]
R2#sh ip route rip
20.0.0.0/24 is subnetted, 1 subnets
R       20.1.1.0 [120/1] via 172.12.123.1, 00:00:26, Serial0/0
10.0.0.0/24 is subnetted, 1 subnets
R       10.1.1.0 [120/1] via 172.12.123.1, 00:00:26, Serial0/0
15.0.0.0/24 is subnetted, 1 subnets
R       15.1.1.0 [120/1] via 172.12.123.1, 00:00:26, Serial0/0
R2#conf t
Enter configuration commands, one per line.  End with CNTL/Z.
R2(config)#int s0/0
R2(config-if)#shut
R2(config-if)#
*Mar  1 11:42:32.118: %LINK-5-CHANGED: Interface Serial0/0, changed state to administratively down
*Mar  1 11:42:33.120: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/0, changed state to down
R2(config-if)#do show ip route eigrp

R2(config-if)#

There is nothing at all to display, and that is because EIGRP much alike RIP does not have a default or ‘seed’ metric for Redistribution, so if you do not enter metric values using either of the above methods than we do not get EIGRP Redistribution of RIP routes!

 

Now to work with Administrative Distance on the Boarder Router

First I wanted to try the “distance # (IP) (WC Mask)” first to see how this would react with EIGRP, as with OSPF it uses the sources routers RID but EIGRP has no RID to be used:

R2(config-router)#distance 119 30.1.1.3 0.0.0.0
R2(config-router)#^Z
R2#
*Mar  1 13:45:39.095: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor 30.1.1.5 (FastEthernet0/0) is down: route configuration changed
*Mar  1 13:45:39.095: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor 30.1.1.4 (FastEthernet0/0) is down: route configuration changed
*Mar  1 13:45:39.099: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor 30.1.1.3 (FastEthernet0/0) is down: route configuration changed
R2#clear
*Mar  1 13:45:40.157: %SYS-5-CONFIG_I: Configured from console by console
*Mar  1 13:45:40.237: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor 30.1.1.5 (FastEthernet0/0) is up: new adjacency
*Mar  1 13:45:40.249: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor 30.1.1.4 (FastEthernet0/0) is up: new adjacency
*Mar  1 13:45:40.253: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor 30.1.1.3 (FastEthernet0/0) is up: new adjacency
R2#show ip route
[Route codes redacted]

Gateway of last resort is not set

2.0.0.0/32 is subnetted, 1 subnets
C       2.2.2.2 is directly connected, Loopback2
20.0.0.0/24 is subnetted, 1 subnets
R       20.1.1.0 [120/1] via 172.12.123.1, 00:00:17, Serial0/0
172.12.0.0/24 is subnetted, 1 subnets
C       172.12.123.0 is directly connected, Serial0/0
10.0.0.0/24 is subnetted, 1 subnets
R       10.1.1.0 [120/1] via 172.12.123.1, 00:00:17, Serial0/0
30.0.0.0/24 is subnetted, 1 subnets
C       30.1.1.0 is directly connected, FastEthernet0/0
15.0.0.0/24 is subnetted, 1 subnets
R       15.1.1.0 [120/1] via 172.12.123.1, 00:00:18, Serial0/0

So this essentially changed nothing in the case of Redistribution, and this has not been covered yet in material I have studied (which all uses ‘distance eigrp …’), so I have to assume this changes the distance of Internal EIGRP routes which I will later try to confirm.

However, I did confirm with EIGRP, the distance command by itself did use the source routers neighbor interface address, as the adjacencies did drop but immediately reformed, so it did change something on the network – Unfortunately my AS is all on one Ethernet segment so there isn’t any dynamic learning of routes at this time. VERY INTERESTING.

Moving right along, we will do this the tried and true method using ‘distance eigrip …’:

R2(config-router)#distance eigrp 90 119
R2(config-router)#do show ip route
[Route codes redacted]

Gateway of last resort is not set

2.0.0.0/32 is subnetted, 1 subnets
C       2.2.2.2 is directly connected, Loopback2
20.0.0.0/24 is subnetted, 1 subnets
D EX    20.1.1.0 [119/1660672] via 30.1.1.3, 00:02:03, FastEthernet0/0
172.12.0.0/24 is subnetted, 1 subnets
C       172.12.123.0 is directly connected, Serial0/0
10.0.0.0/24 is subnetted, 1 subnets
D EX    10.1.1.0 [119/1660672] via 30.1.1.3, 00:02:03, FastEthernet0/0
30.0.0.0/24 is subnetted, 1 subnets
C       30.1.1.0 is directly connected, FastEthernet0/0
15.0.0.0/24 is subnetted, 1 subnets
D EX    15.1.1.0 [119/1660672] via 30.1.1.3, 00:02:04, FastEthernet0/0

A couple of important thing to note with the above command, and following output:

• When entering the command, the first number is Internal AD and the second is External routes AD, I did not need to type internal or external, and Internal will always come before the external #
• I provided an External AD lower than RIP’s default AD of 120, so routes leading to the NBMA RIP network are now being placed into the route table, as when two paths to the same destination are presented to a router the lowest AD is the tie breaker
• “Distance eigrp …” is the option you MUST use to change the AD of routes being Redistributed, however there is no further options to filter changes to Administrative Distance so you must use a Distribution-List on the ASBR to filter routes

And this is where the lesson ends on Changing the Seed Metric and Administrative Distance for EIGRP, as now we have come to the point that to filter certain routes, change the AD for certain routes, etc, we will need Distribution-Lists and even Route-Maps on the router doing the Redistribution to make that happen.