RACKLEY@MSSTATE.BITNET (Mike Rackley) (06/25/88)
I attempted to post this question to the BIG-LAN discussion group about a week ago, but I think it got lost in transit. Anyhow, I apologize if you have seen this before. As we plan or campus network, we have decided to use 4 level domain names of the form: host.dept.MSSTATE.EDU. This seems to be in line with what a lot of other universities do. We also plan to assign internet addresses in a subnetted fashion even though initially we will be using MAC layer bridges instead of routers for traffic isolation. I am confused about the relationship of domains and subnets. Is there, or should there be, any specific relationship between domains and subnets? In particuar, is it possible to have a single domain that contains more than one subnet? Conversely, is it possible to have a single subnet that contains more than one domain? Can you have a single domain that is spread among several subnets? The situation I am wondering about is where a department is spread among several buildings on campus. Mike Rackley Mississippi State University
alan@cunixc.columbia.edu (Alan Crosswell) (06/27/88)
In article <8806270548.AA23542@ucbvax.Berkeley.EDU> RACKLEY@MSSTATE.BITNET (Mike Rackley) writes: >I am confused about the relationship of domains and subnets. Is there, >or should there be, any specific relationship between domains and subnets? >In particuar, is it possible to have a single domain that contains more than >one subnet? Conversely, is it possible to have a single subnet that contains >more than one domain? Can you have a single domain that is spread among >several subnets? The situation I am wondering about is where a department is >spread among several buildings on campus. Domains are basically a *user* convenience for naming an IP address. There is no required relationship between a domain name and an IP address, network, subnet, campus, etc. In usual practice they happen to correspond since single departments tend to be on a single subnet. However, it is perfectly reasonable to have members of the same subdomain be located on radically different networks (e.g. on opposite sides of the world). You just better hope that a domain name server for that domain is reachable from both those networks (not necessarily the same one!). A lot of people get domains and networks locked together in their minds mainly as a result of poor examples of domain usage like .BITNET and .UUCP where the domain is actually being used to indicate a specific non-IP network. Work is progressing in both these networks to convert to proper domain names. There are now many "MX" servers on the Internet that respond to domain lookups for BITNET and UUCP hosts. Alan Crosswell Columbia University
DCP@QUABBIN.SCRC.SYMBOLICS.COM (David C. Plummer) (06/27/88)
Date: Sat, 25 Jun 88 08:00:04 CDT
From: Mike Rackley <RACKLEY%MSSTATE.BITNET@CUNYVM.CUNY.EDU>
...
I am confused about the relationship of domains and subnets. Is there,
or should there be, any specific relationship between domains and subnets?
They are completely orthogonal. You can, if you want, establish
relationships, but it would be for purely personal and/or administrative
reasons; there would be (and can be) no technical reason for doing so.
The basic thing to remember is that domains are an administrative naming
system, whereas subnets are a physical cable numbering system (more or
less).fin@uf.msc.umn.EDU (Craig Finseth) (06/27/88)
There is no need for any particular relationship between domains and subnets. You may choose -- for administrative ease -- to divvy up the subnet address space into blocks for each department. In that case, you will likely have some departments that occupy lots of subnets and other groups of departments that share a subnet. My advice is to have a central authority give out subnets on demonstrated need (e.g., new building or >200 or so hosts alread in place). In many places, once you give out a subnet, it becomes difficult to get back if the campus' needs as a whole should change. Craig A. Finseth fin@uc.msc.umn.edu [CAF13] Minnesota Supercomputer Center, Inc. (612) 624-3375