EIGRP topology Question

From: Andy (ccie@jzr.com)
Date: Sat Jan 10 2004 - 01:55:40 GMT-3


I have question about eigrp topology output. I think I'm seeing weird
behavior.

I have a topology which is essentially a box.
R3---R4
| |
R5---R6

R3/R4 network 13.1.1.0/24
R5/R6 20.1.1.0/24
R3/R5 12.1.1.0/30
R4/R6 12.1.1.4/30

I'm looking at the "sho ip route", "sho ip eigrp topology" and "show ip
topology 13.1.1.0 255.255.255.0" commands.

Based on the metrics, from R6 I would expect to see that the preferred
path is via R4. Referring to the show commands this is what I see.

What I'm having a problem understanding is the "show ip topology
13.1.1.0 255.255.255.0" command. The path to 13.1.1.0 still displays
via R5 (20.1.1.5) even though the Advertised distance for 13.1.1.0 from
R5 (320000) is greater than the FD (307200). Is this the correct
behavior?

This doesn't seem right to me since it does not meet the feasible
condition (assuming I understand it correctly).

Tia,
Andy
R6#
R6#sho ip eigrp top
R6#sho ip rou
Codes: 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, 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

Gateway of last resort is not set

     55.0.0.0/24 is subnetted, 2 subnets
D EX 55.55.55.0 [170/284160] via 12.1.1.6, 00:00:42, Ethernet1/0
D EX 55.5.5.0 [170/284160] via 12.1.1.6, 00:00:42, Ethernet1/0
     20.0.0.0/24 is subnetted, 1 subnets
C 20.1.1.0 is directly connected, Ethernet0/0
     66.0.0.0/24 is subnetted, 2 subnets
C 66.2.2.0 is directly connected, Loopback0
D EX 66.1.1.0 [170/409600] via 20.1.1.5, 00:02:22, Ethernet0/0
     10.0.0.0/24 is subnetted, 1 subnets
D EX 10.1.1.0 [170/284160] via 12.1.1.6, 00:00:42, Ethernet1/0
     11.0.0.0/30 is subnetted, 2 subnets
D EX 11.1.1.0 [170/284160] via 12.1.1.6, 00:00:42, Ethernet1/0
D EX 11.1.1.4 [170/284160] via 12.1.1.6, 00:00:42, Ethernet1/0
     12.0.0.0/30 is subnetted, 2 subnets
C 12.1.1.4 is directly connected, Ethernet1/0
D 12.1.1.0 [90/320000] via 20.1.1.5, 00:00:53, Ethernet0/0
     13.0.0.0/24 is subnetted, 1 subnets
D 13.1.1.0 [90/307200] via 12.1.1.6, 00:00:43, Ethernet1/0
R6#sho ip eigrp top
R6#sho ip eigrp topology
IP-EIGRP Topology Table for AS(1)/ID(66.2.2.2)

Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply,
       r - reply Status, s - sia Status

P 12.1.1.4/30, 1 successors, FD is 281600
         via Connected, Ethernet1/0
P 10.1.1.0/24, 1 successors, FD is 284160, tag is 11
         via 12.1.1.6 (284160/258560), Ethernet1/0
P 11.1.1.0/30, 1 successors, FD is 284160, tag is 11
         via 12.1.1.6 (284160/258560), Ethernet1/0
P 12.1.1.0/30, 1 successors, FD is 307200
         via 20.1.1.5 (320000/294400), Ethernet0/0
P 13.1.1.0/24, 1 successors, FD is 307200
         via 12.1.1.6 (307200/281600), Ethernet1/0
P 11.1.1.4/30, 1 successors, FD is 284160, tag is 11
         via 12.1.1.6 (284160/258560), Ethernet1/0
P 20.1.1.0/24, 1 successors, FD is 281600
         via Connected, Ethernet0/0
P 55.55.55.0/24, 1 successors, FD is 284160, tag is 11
         via 12.1.1.6 (284160/258560), Ethernet1/0
P 55.5.5.0/24, 1 successors, FD is 284160, tag is 11
         via 12.1.1.6 (284160/258560), Ethernet1/0
P 66.1.1.0/24, 1 successors, FD is 409600
         via 20.1.1.5 (409600/128256), Ethernet0/0
P 66.2.2.0/24, 1 successors, FD is 128256
         via Rconnected (128256/0)

R6#sho ip eigrp topology 13.1.1.0 255.255.255.0
IP-EIGRP (AS 1): Topology entry for 13.1.1.0/24
  State is Passive, Query origin flag is 1, 1 Successor(s), FD is 307200
  Routing Descriptor Blocks:
  12.1.1.6 (Ethernet1/0), from 12.1.1.6, Send flag is 0x0
      Composite metric is (307200/281600), Route is Internal
      Vector metric:
        Minimum bandwidth is 10000 Kbit
        Total delay is 2000 microseconds
        Reliability is 255/255
        Load is 1/255
        Minimum MTU is 1500
        Hop count is 1
  20.1.1.5 (Ethernet0/0), from 20.1.1.5, Send flag is 0x0
      Composite metric is (345600/320000), Route is Internal
      Vector metric:
        Minimum bandwidth is 10000 Kbit
        Total delay is 3500 microseconds
        Reliability is 255/255
        Load is 1/255
        Minimum MTU is 1500
        Hop count is 2
R6#



This archive was generated by hypermail 2.1.4 : Mon Feb 02 2004 - 09:07:39 GMT-3