eigrp

[carl_townshend]

If I have 2 routers connected to my core and im running eigrp and the 2 other routers are advertising the same network, both the same speed links and delays etc, would they load balance or would eigrp pick on and use the other as backup, and if so How could I manually pic the router I wanted it to use ?

thanks

Carlos

[mahmoodmkl]

Hi carl

If they are having the same speeds and delay etc EIGRP will load balance.if they r advertising the same network then i think it will keep the other route as feasable successor.

thanks

Mahmood

[nbhandarkar]

By default, EIGRP puts upto 4 routes of equal cost into the routing table and load-balances among them.

You can configure Eigrp to take upto 6 equal cost paths.

You can check this link

http://www.cisco.com/en/US/tech/tk365/technologies_white_paper09186a0080094cb7.shtml#loadbalancing

[carl_townshend]

thanks for that, how would I know its load balancing, would it show 2 successors ? and if I dont want it to load balance how would I manipulate the bandwidth so it uses just the one path ?

thanks

[nbhandarkar]

Yes. It would show 2 successors.

You can manipulate the bandwidth of any of the two links of your preference using the "bandwidth" command on the interface so that Eigrp recalculates the FD of the affected link. If the new FD is the lowest for that network, then packets will be routed thru this link.

You can also try to disable load-balancing using the "maximum-paths 1" in router config mode. By doing so, it will choose only one path depending on which one it received first.

[carl_townshend]

How would I know what bandwidth its currently using ? and If so would I just put a higher bandwidth in on that link ?

[nbhandarkar]

Do a "show interface" to check the bandwidth that is currently configured for the interface. If bandwidth command is explicitly configured, then it will be used; otherwise it will take the default bandwidth for that interface.

Always remember that the "bandwidth" command does not affect the speed of the link. It is only used for metric calculation. So you can configure a higher bandwidth to force EIGRP to prefer this link for routing traffic.

And also note that the EIGRP bandwidth is calculated as (10000000/least BW in the entire path)*256.

Check out this link. You can also find more docs on Cisco reg manipulating the metric of EIGRP.

http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a008009405c.shtml

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