Load balance with EIGRP

charl · ‎03-23-2011

Hi I have problem with load balancing (per-destination) across 2 x 2MB serial links, it only works from A-site to B-site, but not from B-site to A-site

The Eigrp ajacency is ok, but traffic is only using one link(Serial0/1/0) from B-site to A-site and not the other Serial 0/0/0.

Any Ideas ? See output bellow....

B-site-rtr#sh ip route 1.1.2.0 -> this is to the A-site

Routing entry for 1.1.2.0/22

Known via "eigrp 2000", distance 90, metric 1762304, type internal

Redistributing via eigrp 2000

Last update from 1.1.2.50 on Serial0/1/0, 00:15:01 ago

Routing Descriptor Blocks:

* 1.1.2.50, from 1.1.2.50, 00:15:01 ago, via Serial0/1/0

Route metric is 1762304, traffic share count is 1

Total delay is 20020 microseconds, minimum bandwidth is 2048 Kbit

Reliability 255/255, minimum MTU 1500 bytes

Loading 98/255, Hops 2

B-site-rtr#sh ip eigrp topology 1.1.2.0 255.255.252.0

EIGRP-IPv4 Topology Entry for AS(2000)/ID(1.1.4.5) for 1.1.2.0/22

State is Passive, Query origin flag is 1, 1 Successor(s), FD is 1762304

Descriptor Blocks:

1.1.2.50 (Serial0/1/0), from 1.1.2.50, Send flag is 0x0

Composite metric is (1762304/3072), route is Internal

Vector metric:

Minimum bandwidth is 2048 Kbit

Total delay is 20020 microseconds

Reliability is 255/255

Load is 98/255

Minimum MTU is 1500

Hop count is 2

1.1.2.53 (Serial0/0/0), from 1.1.2.53, Send flag is 0x0

Composite metric is (1762304/3072), route is Internal

Vector metric:

Minimum bandwidth is 2048 Kbit

Total delay is 20020 microseconds

Reliability is 255/255

Load is 1/255

Minimum MTU is 1500

Hop count is 2

cadet alain · ‎03-24-2011

Hi,

Can you do sh ip protocols | be eigrp on router B please

Regards.

Alain.

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charl · ‎03-24-2011

Hi Alain, Here is the output bellow:

I see the Distance for the one link is 170 ? Not sure why this is caused ? - I guess this looks like un-equal cost ?

B-rtr#sh ip protocols

*** IP Routing is NSF aware ***

Routing Protocol is "eigrp 2000"

Outgoing update filter list for all interfaces is not set

Incoming update filter list for all interfaces is not set

Default networks flagged in outgoing updates

Default networks accepted from incoming updates

Redistributing: eigrp 2000

EIGRP-IPv4 Protocol for AS(2000)

Metric weight K1=1, K2=0, K3=1, K4=0, K5=0

NSF-aware route hold timer is 240

Router-ID: 1.1.4.5

Topology : 0 (base)

Active Timer: 3 min

Distance: internal 90 external 170

Maximum path: 4

Maximum hopcount 100

Maximum metric variance 1

Automatic Summarization: disabled

Maximum path: 4

Routing for Networks:

1.1.2.0/24

1.2.1.0/28

Routing Information Sources:

Gateway Distance Last Update

(this router) 90 1d00h

1.1.2.50 90 00:12:01 - > S0/0/1

1.1.2.53 170 00:11:12 - > S0/0/0

172.25.101.2 90 00:11:12

172.25.101.14 90 00:11:12

Distance: internal 90 external 170

If I shut the Serial that takes all the traffic to force traffic to Serial 0/0/0 I see :

B-rtr#sh ip route 1.1.2.0

Routing entry for 1.1.2.0/22

Known via "eigrp 2000", distance 170, metric 1762304, type internal

Redistributing via eigrp 2000

Last update from 1.1.2.53 on Serial0/0/0, 00:02:48 ago

Routing Descriptor Blocks:

* 1.1.2.53, from 1.1.2.53, 00:02:48 ago, via Serial0/0/0

Route metric is 1762304, traffic share count is 1

Total delay is 20020 microseconds, minimum bandwidth is 2048 Kbit

Reliability 255/255, minimum MTU 1500 bytes

Loading 1/255, Hops 2

skarthic · ‎03-24-2011

Looks like the second route is getting redistributed into EIGRP.. Is site A redisributing the routes from another Autonomous System?

Any idea if there are multiple AS involved.

cadet alain · ‎03-24-2011

Hi,

1.1.2.53 (Serial0/0/0), from 1.1.2.53, Send flag is 0x0

Composite metric is (1762304/3072), route is Internal

If the route was redistributed the route would be external

I think the AD of some advertised routes has been modified.

Could you do a sh run | be router ei, sh route-map , sh access-list

Regards.

Alain.

Don't forget to rate helpful posts.