Talk:Classless Inter-Domain Routing
Prefix/suffix
I'm not quite sure here, but shouldn't "prefix" be replaced with "suffix" instead? --Maik
I think the usual terminology is prefix, since you route packets destined for 193.137.7.30 (for example) through the shortest path to the 193.137.7/24 prefix (which itself is aggregated and reachable through the 193.136/15 prefix (which is composed of the 193.136/16 prefix and the 193.137/16 prefix)).
The term prefix makes sense when you consider how the netmask is expressed in binary Robertbrockway 04:40, Apr 18 2005 (UTC)
Confusion
How in the heck did I interpret 4 minutes as 3 months??!? - Lucky13pjn 19:48, Mar 14, 2005 (UTC)
Example
The example about the /22 mask lists a Class-C address (192.168.0.0) but the default mask for Class-C is 255.255.255.0 or /24. I thought that you could only add ones bits to the default mask, not take them away. Wouldn’t a /22 mask have to be associated with a Class-A or B address?
This is the example given:
“192.168.0.0 /22 could be written 192.168.0.0 255.255.252.0”
Should it have been something like:
“172.168.0.0 /22 could be written 172.168.0.0 255.255.252.0”
--addnet 18:51, 23 July 2005 (UTC)
The restriction on taking bits away from the default mask only applied in the classful networking scheme. Classless routing is just what its name implies — you really don't have any restrictions anymore on what can be done to a "class A" or a "class C" address. With the exception of class D/E, the entire address space is now administered uniformly throughout. So there are no more "classes". Really.
Origins of CIDR
The first person to suggest using a net-mask to cover a group of classful networks (as opposed to subnets of a single classful network) was Carl-Hubert Rokitansky (affectionately known as "Roki" to all :-), in his "Cluster Networking" proposal (which long predated CIDR). (See this message and this reply to the internet-history mailing list.)
I had thought for a long time that there were no original documents on line for this proposal; web searches revealed nothing. However, I have just discovered that the online copy (large [[Portable Document Format|pdf] file) of the Proceedings of the '1st' IETF (there was actually at least one earlier one) includes a copy of Roki's handwritten slides on the matter, on pp. 45-61 (pdf page numbers). Just noting this here for informational purposes! Noel (talk) 16:11, 16 September 2005 (UTC)
Order, Order
I like the way you use a notation ie : " ... sixteen contiguous /24 networks ... " which is meaningless until you read later what the / means. Maybe you could assume the reader is new to the ideas of Classless Inter-Domain Routing, which is why he/she came to the page.
Similarly " ... The class, and hence the length of the subnet mask ...", before explaining what a subnet mask is. Very odd. I assume you are writing this for the people who already know it all, and just need a reminder?
Point taken. I think it's better now.