Anytime you run multiple protocols on a single LAN, network performance will be impacted. This is even more so the case with NetBEUI, as it is entirely broadcast-based in nature. Unless you have a specific need to run NetBEUI, I would recommend disabling it at the server and workstations as quickly as possible; your users will thank you. If that is not a possibility, attempt to isolate the users who require NetBEUI onto a single router segment; since it is a non-routable protocol, this will protect the remainder of your network from being bombarded with unnecessary broadcast traffic.
This was first published in November 2002