computers on the network

Does anyone know of any documentation on XP machines when joining a workgroup or domain are unable to see other computers on the network, then all of the sudden they can, then they can’t again and back. Or laptops that are off of the network for a while and when connected back to the network can’t see other machines, only themselves? I have encountered this problem with my home network, the one at my office and have heard from other techs with the same issue. If Microsoft has any documentation of this and anyone could point me in the right direction, it would be greatly appreciated. Thanks.