Set metric +/-<metric> on route-map for EIGRP

Hi All,

While using route-map in the eigrp distribute-list, when I was configuring the metric, I stumble across a problemb&I wanted to offset the composite metric by a value so I used the command bset metric +1000000b but it did not have any impact.. Even if I use bset metric 1000000b, it still did not have any impact.. Then I kept increasing the metric value and at certain value it start taking effect.. So, I realized that set metric command will only work when the new metric is higher than the existing composite metric for that route and also b+<metric>b does not do any offset or add to the current composite metric.. Can anyone explain this behaviour ? Is there any way to implement the offset metric feature with route-map ?

## with No metric statement
R1# sh route-map FTAG-BA2MSG
route-map FTAG-BA2MSG, permit, sequence 10
  Match clauses:
    tag 193
  Set clauses:
  Policy routing matches: 0 packets, 0 bytes

R2#sh ip eigrp topology 172.24.225.0 255.255.255.0
EIGRP-IPv4 Topology Entry for AS(1)/ID(10.30.128.7) for 172.24.225.0/24
  State is Passive, Query origin flag is 1, 1 Successor(s), FD is 1028864
  Descriptor Blocks:
  10.25.128.10 (GigabitEthernet2/3), from 10.25.128.10, Send flag is 0x0
      Composite metric is (1028864/1028608), route is External
      Vector metric:
        Minimum bandwidth is 2500 Kbit
        Total delay is 190 microseconds
        Reliability is 255/255
        Load is 3/255
        Minimum MTU is 1500
        Hop count is 5
      External data:
        Originating router is 10.30.192.3
        AS number of route is 0
        External protocol is Connected, external metric is 0
        Administrator tag is 193 (0x000000C1)

## with metric statement set in R1

R1#sh route-map FTAG-BA2MSG
route-map FTAG-BA2MSG, permit, sequence 10
  Match clauses:
    tag 3
  Set clauses:
    metric 1000000 <-- metric set
  Policy routing matches: 0 packets, 0 bytes

R2#sh ip eigrp topology 172.24.225.0 255.255.255.0
EIGRP-IPv4 Topology Entry for AS(1)/ID(10.30.128.7) for 172.24.225.0/24
  State is Passive, Query origin flag is 1, 1 Successor(s), FD is 1028864
  Descriptor Blocks:
  10.25.128.10 (GigabitEthernet2/3), from 10.25.128.10, Send flag is 0x0
      Composite metric is (1028864/1028608), route is External <-- No change in Composite metric in R2
      Vector metric:
        Minimum bandwidth is 2500 Kbit
        Total delay is 190 microseconds
        Reliability is 255/255
        Load is 3/255
        Minimum MTU is 1500
        Hop count is 5
      External data:
        Originating router is 10.30.192.3
        AS number of route is 0
        External protocol is Connected, external metric is 0
        Administrator tag is 193 (0x000000C1)

## with +metric statement set in R1

R1#sh route-map FTAG-BA2MSG
route-map FTAG-BA2MSG, permit, sequence 10
  Match clauses:
    tag 3
  Set clauses:
    metric +1000000 <-- + metric set
  Policy routing matches: 0 packets, 0 bytes

R2#sh ip eigrp topology 172.24.225.0 255.255.255.0
EIGRP-IPv4 Topology Entry for AS(1)/ID(10.30.128.7) for 172.24.225.0/24
  State is Passive, Query origin flag is 1, 1 Successor(s), FD is 1028864
  Descriptor Blocks:
  10.25.128.10 (GigabitEthernet2/3), from 10.25.128.10, Send flag is 0x0 o still No change in the composite metric. Still backup route is preferred
      Composite metric is (1028864/1028608), route is External <-- No change in Composite metric in R2
      Vector metric:
        Minimum bandwidth is 2500 Kbit
        Total delay is 190 microseconds
        Reliability is 255/255
        Load is 3/255
        Minimum MTU is 1500
        Hop count is 5
      External data:
        Originating router is 10.30.192.3
        AS number of route is 0
        External protocol is Connected, external metric is 0
        Administrator tag is 193 (0x000000C1)

## Increase the metric higher than the current composite metric for that route

R1#sh route-map FTAG-BA2MSG

route-map FTAG-BA2MSG, permit, sequence 10 o Set the metric value to 1050000
  Match clauses:
    tag 3
  Set clauses:
    metric 1050000 <-- metric value higher than the current composite metric
  Policy routing matches: 0 packets, 0 bytes

R2#sh ip eigrp topology 172.24.225.0 255.255.255.0
10.25.128.10 (GigabitEthernet2/3), from 10.25.128.10, Send flag is 0x0
      Composite metric is (268800256/268800000), route is External <- Change took effect
      Vector metric:
        Minimum bandwidth is 9 Kbit
        Total delay is 10 microseconds
        Reliability is 0/255
        Load is 3/255
        Minimum MTU is 241
        Hop count is 5
      External data:
        Originating router is 10.30.192.3
        AS number of route is 0
        External protocol is Connected, external metric is 0
        Administrator tag is 193 (0x000000C1)

Blogs and organic groups at http://www.ccie.net
Received on Tue Jan 07 2014 - 17:04:06 ART