Talk:Classless Inter-Domain Routing

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Latest comment: 19 years ago by Jnc in topic Origins of CIDR

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)Reply

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)Reply


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?