Balance network traffic over two gateways

[ASSIST]

I have two routers on my network that connect with the same network....

I want to know if I can define gated to balance network traffic over the two WAN links to reach the same destination (with ospf or some similar)

thanks in advance

[Christopher Caldwell]

Yes. If it's cisco, you can per packet or per destination load balance. It's easy. Equal cost routes through each interface causes load balacing. Look at other features (like fast switching) to decide whether to perform per packet or per destination load balacing.

You can also use route-maps to deal with source based load balacing, but route-maps are very CPU intensive.

Other than Cisco, YMMV.

[ASSIST]

Cristopher

I know that I can make this with a Cisco Router

But what i want is use the HP9000 as default gateway of my network and balance trafic over two cisco routers that connects against other network

Do you know if HPUX can make this?

Thanks!

[Christopher Caldwell]

HP won't load balance, per se. So the default route trick won't balance traffic through the HP interfaces using static routes.

On HP, the last route entered wins. That's the prevailing route until the route disappears.

[rick jones]

A couple things - unless you know beyond a shadow of a doubt that per-packet load balancing will not reorder packets of a given TCP connection, DON"T USE IT - reordering TCP segments, while not "breaking" anything will play havoc with performance.

Now, if you have two routers on the same LAN, and they are to be your "default" route, and if they support Proxy ARP, you can change the default route on the HP-UX system to point to the UX system's own local IP (with a metric of 0 rather than one). Then for each remote IP destination, the UX system will ARP, and the routers can decide among themselves which one should reply.

If they are able to go back and forth on who answers ARPs, you will have per-destination load balancing.

I suspect that there might be ways to get slighly similar load balancing running a gated that was only listening to router protocol traffic, but I think the proxy arp mechanism would be much simpler. Most folks (myself included) should be very wary of messing with routing daemons.