At 10:44 10/10/2006, Michael.Dillon@btradianz.com wrote:
- 'Canonical representation of 4-byte AS numbers '
http://www.ietf.org/internet-drafts/draft-michaelson-4byte-as-representation...
and what is good or bad about this representation? seems simple to me. and having one notation seems reasonable. what am i missing?
It breaks any applications which recognize IP address-like objects by seeing a dot in an otherwise numeric token.
Well, it will break an applications that considers everything consisting of numbers and dots to be an IP address/netmask/inverse mask. I don't think many applications do this, as they will then treat the typo "193.0.1." as an IP address. It won't break applications that check if there are exactly 4 numbers in the 0-255 range and 3 dots. The alternative notation (x:y) is much worse in this respect. "x:y" is something (a community string). "x.y" is not.
The real question is what does the notation 1.0 add that the notation 65536 does not provide?
It is (for me, and I guess most other humans) much easier to read and remember, just as 193.0.1.49 is easier to read and remember than 3238002993. It also reflects that on the wire there are two 16 bit numbers, rather than 1 32-bit number. More important: I think it is a mistake to assume that using AS65536 will NOT break things: 1. If you are a 16-bit AS speaker (ASN16), then AS65536 is not just the next one in the line, it is an AS that will have to be treated differently. The code has to recognize it and replace it by the transistion mechanism AS. 2. Just as people having used the regexps that you mentioned, I'm also certain that people have used unsigned short int's or signed long int's in their code. In short, like it or not, you will have to check and update your tools anyway.
If the IETF had really wanted
The IETF process is open and you can still comment on the issue. Henk ------------------------------------------------------------------------------ Henk Uijterwaal Email: henk.uijterwaal(at)ripe.net RIPE Network Coordination Centre http://www.amsterdamned.org/~henk P.O.Box 10096 Singel 258 Phone: +31.20.5354414 1001 EB Amsterdam 1016 AB Amsterdam Fax: +31.20.5354445 The Netherlands The Netherlands Mobile: +31.6.55861746 ------------------------------------------------------------------------------ 1160438400 + 381600 = 1160820000.