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xbw
New Member

Two wan interfaces (wic cards) need to load balance!

I am trying to implement loading-balance between two wan interfaces on one router.There is my network topology in attachment.How can I do.Any help would be appreciated as I am still fairy new to config'ing cisco routers.

6 REPLIES
New Member

Re: Two wan interfaces (wic cards) need to load balance!

What is DDN on your picture?

//Mikhail Galiulin

xbw
New Member

Re: Two wan interfaces (wic cards) need to load balance!

ddn is Digital Data Network,similar to frame-relay or sdh.I want to implement bidirectional load-balancing between two sites.and the two routes is unequal.how can I do?Please help me ,thanks!

New Member

Re: Two wan interfaces (wic cards) need to load balance!

If two routes are unequal then you should use EIGRP.

I never did this myself with EIGRP (only with OSPF on two equal-cost FR links), but it seems that follwing document gives quite a good explanation to start with:

http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a008009437d.shtml

But be carefull with load-balancing over links of different types - some applications are quite sensitive to packets coming in wrong order.

//Mikhail Galiulin

Purple

Re: Two wan interfaces (wic cards) need to load balance!

Hi,

The Cisco IOS inherently supports load-balancing when 2 or more "equal-cost" routes to the same destination are present. For two routes to be deemed equal cost, they must have the same administrative distance and metric. Protocols such as EIGRP and IGRP also support unequal-cost load sharing.

In your case, one of the things you could so is just add two static routes to 0.0.0.0 as such:

ip route 0.0.0.0 0.0.0.0

ip route 0.0.0.0 0.0.0.0

and the router will automatically start load-balancing over your two links. The type of load-balancing will depend on the switching method used on your router:

- process switching: load balancing is on a per-packet basis

- fast-switching: load balancing is on a per-destination basis

- CEF-switching: load balancing can be on either a per-packet or per-destination basis.

The following link talks more about these options:

http://www.cisco.com/warp/public/105/46.html

Hope that helps,

Paresh.

xbw
New Member

Re: Two wan interfaces (wic cards) need to load balance!

Does cisco 2600 have the function of cef?

New Member

Re: Two wan interfaces (wic cards) need to load balance!

Depends of the IOS version.

Run "show ip cef" to see whether your image supports it.

//Mikhail Galiulin

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