If you have kixtart locally on each workstation, there is no problem with bandwidth.
You can also use a local cache for scripts.
at my office, the login script begins with a robocopy of netlogon in a local directory. After, the local scripts are launched.
Take care !!!
usually the login script is not really the longest part of a connection (except if you are doing very complex opeartions). When a user logs on, the loading of the profile and the policies may be "very long" and you can't do any thing to accelerate.
_________________________
Christophe
