Load Balancing and Varnish

[Allan Brand]

Greetings,

I'm new to Varnish and I've seen a number of discussions where Varnish
is used in conjunction with a load balancer in the following manner:
[LB] -> [Varnish] -> [www 1-n]

I'm guessing that Varnish is running locally on the www hosts?  If
not, Is there any reason why placing Varnish in front of the load
balancers instead would not be ideal?
[Varnish] -> [LB} -> [www 1-n]

Thanks,
Allan