Re: Equal-cost path

[Dave Katz <[e-mail]>]

On Apr 13, 2005, at 7:38 AM, Naidu, Venkata wrote:

>  If we assuming all nodes in an area have same
>  capabilities (like, line rate forwarding etc), fewer number
>  node path performs better in the average case.
>

I do not believe that you can make this claim, except in a simulation, 
which has little to do with reality.

In real networks, with reasonably fast routers and links, the 
performance of the routers and per-link serialization are greatly 
overwhelmed by other issues (such as the speed of light and queue 
lengths.)

One could just as plausibly posit that, on average, a random assignment 
in the case of equal path costs could improve performance by spreading 
the load more effectively across the infrastructure, but it totally 
depends on the particulars of equipment, topology, and traffic.

A case could also be made that well-engineered networks ought not to 
have equal cost paths by accident;  most of the time they should only 
appear if the network engineers wanted to take advantage of path 
splitting.

In any case, a router that did not support equal cost multipath would 
be so broken that nobody would buy it, making the whole question 
academic.

--Dave