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EIGRP ip summary-address not propagating correctly

Hi,

We have a strange routing issue with summary routes and redistributed routes. Network topology is configured in a ring of nine switches. It appears that the manually configured summary addresses don't get propagated around the network. For example a summary address will only be propagated for 5 hops and then not any further the result being most of the switches only having one path of advertised for that summary. If a switch in the ring fails some of the switches become unavailable to each other based on hop count. We don't have any issues with connected routes being propagated around the network. The switches involved are 7 x Cisco  WS-C3850-24P and we have 2 x 4500X. We have only just recently upgraded the network from Cisco 3750 to 3850. Under the previous hardware we didn't have any of these issues using the same configuration.

 

Here's an example from one of the switch when we run show ip eigrp top 10.241.0.0/19:

 

#show ip eigrp top 10.241.0.0/19
EIGRP-IPv4 Topology Entry for AS(20)/ID(10.255.255.7) for 10.241.0.0/19
  State is Passive, Query origin flag is 1, 1 Successor(s), FD is 3584
  Descriptor Blocks:
  10.255.0.13 (Port-channel1), from 10.255.0.13, Send flag is 0x0
      Composite metric is (3584/3328), route is Internal
      Vector metric:
        Minimum bandwidth is 1000000 Kbit
        Total delay is 40 microseconds
        Reliability is 255/255
        Load is 1/255
        Minimum MTU is 1500
        Hop count is 3
        Originating router is 10.255.255.4

 

The summary for 10.241.0.0/19 is only 3 hops away which it shows but this switch should be showing another path to this summary route which is 6 hops away but its not. If I run the same command on the next switch in the loop it shows both paths to the summary as shown below:

show ip eigrp top 1.241.0.0/19
EIGRP-IPv4 Topology Entry for AS(20)/ID(10.255.255.8)
%Entry 1.241.0.0/19 not in topology table
CON-CP11-SW01#show ip eigrp top 10.241.0.0/19
EIGRP-IPv4 Topology Entry for AS(20)/ID(10.255.255.8) for 10.241.0.0/19
  State is Passive, Query origin flag is 1, 1 Successor(s), FD is 3840
  Descriptor Blocks:
  10.255.0.18 (Port-channel1), from 10.255.0.18, Send flag is 0x0
      Composite metric is (3840/3584), route is Internal
      Vector metric:
        Minimum bandwidth is 1000000 Kbit
        Total delay is 50 microseconds
        Reliability is 255/255
        Load is 1/255
        Minimum MTU is 1500
        Hop count is 4
        Originating router is 10.255.255.4
  10.255.0.21 (Port-channel2), from 10.255.0.21, Send flag is 0x0
      Composite metric is (4096/3840), route is Internal
      Vector metric:
        Minimum bandwidth is 1000000 Kbit
        Total delay is 60 microseconds
        Reliability is 255/255
        Load is 1/255
        Minimum MTU is 1500
        Hop count is 5

 

The switches are all running the same IOS XE version 03.03.03SE. Can someone let me know if this is a bug or something else?

 

Thanks,

Ross.

  • WAN Routing and Switching
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