Global Catalog Servers and WAN traffic

From: Randy (anonymous_at_discussions.microsoft.com)
Date: 04/29/04 

Date: Thu, 29 Apr 2004 08:46:07 -0700

We are planning a migration from nt domain into a new parallel AD domain which is part of a forest of 6 other domains within our worldwide enterprise. All member servers and domain contollers in the new domain will be 2000 and all pc's will be wk2 or xp pro.
All except one of the other domains in our corporate AD forest are in mixed mode, we have approx. 1500 pc's and feel the migration would be much easier with our new domain in native mode and to use the sid history feature to provide back access to nt resources.
However we have be told that we should not go to native mode as ALL authentication would have to go to one of only four gcs in the forest/worldwide, and to put a gcs in all major sites would bring our network to it's knees.
Surely the reason for ms recommending gcs in all major sites is to cut down on network traffic.
Please explain and recommend. thanks