Xref: utzoo comp.protocols.tcp-ip:16162 comp.dcom.sys.cisco:1226 Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!think.com!spool.mu.edu!munnari.oz.au!cs.mu.OZ.AU!cs.mu.oz.au!kre From: kre@cs.mu.oz.au (Robert Elz) Newsgroups: comp.protocols.tcp-ip,comp.dcom.sys.cisco Subject: Re: Partial subnetting Message-ID: Date: 19 May 91 17:52:31 GMT Article-I.D.: mundamut.kre.674675551 References: <=~P_0Q&@warwick.ac.uk> Sender: news@cs.mu.OZ.AU Organization: Comp Sci, University of Melbourne, Australia Lines: 25 cudcv@warwick.ac.uk (Rob McMahon) writes: >A nearby book calls what we are trying to do an "illegal" setup, and says it >is "recommended" to have the same netmask throughout the network. Its not illegal, but its not supported by just about anything yet. However, support for this isn't as hard as was implied by a previous response - routers do need to keep the network mask with every route, but its not essential to use a routing protocol that transmits masks, RIP can cope in this kind of evnironment just fine (and if RIP does, so will just about anything else reasonable - just leave out EGP). What a new routing protocol is needed for is the ability to assign the subet masks in any random fashion - but is you're willing to assign netmasks, and net numbers, in a structured fashion with respect to the physical topology of the net, then it will all work just fine. That restriction is typically not a problem at all in most environments, esp where you have a backbone with a wide subnet mask, and spur nets with narrow masks. If only you could find routers to support it - its not difficult, masks in the routing table, and a little proxy ARP is all that's required. kre