Re: weird ASPATH in update message

[Arife Coltekin <]

Hi Jianhong,

> I downloaded the BGP raw data of update messsage
> on 01/31/2002 from Ripe RRC00, and used route_btoa
> to get the text file for the update events.
> 
> Normally, in the ASPATH part, there are no more than
> 40 unique ASes, But I found that sometimes there are
> more than 100 ASes there and most of them are in brackets.
> What does it mean? Why are there so many ASes in this
> breacket, "[...]"?
> 

That corresponds AS-set. It means announced prefix with AS-set can be 
reachable through any AS numbers which are listed between brackets.

Please, look at the following URL,

http://www.cisco.com/univercd/cc/td/doc/cisintwk/ics/icsbgp4.htm

Regards.
Arife


> Thanks.
> Jianhong
> 
> -----------
> PS:
> 
> Here is an example:
> 
> in the file: updates.20020131.1847
> 
> ....
> ...
> 
> TYPE: BGP4MP/MESSAGE/Update
> FROM: 64.211.147.146 AS3549
> TO: 193.0.0.1 AS12654
> ORIGIN: INCOMPLETE
> ASPATH: 3549 701 23089 [1 3 71 151 226 714 852 1221 1668 2140 2497 2856
> 3303 3320 3360 3489 3599 3703 3758 3908 4546 4628 4637 4657 4694 5006 6253
> 6
> 517 6555 6878 6983 7017 7098 7176 7260 7462 7473 7543 7914 8011 8052 8112
> 8153 9739 9824 10199 10311 10530 10625 10656 10796 10829 10838 10910 10911
>  10947 10994 11015 11060 11101 11351 11354 11426 11427 11492 11521 11532
> 11567 11707 11853 11854 11908 11955 12021 12042 12083 12169 12179 12180
> 122
> 62 12270 12271 13343 13367 13373 13471 13560 13581 13606 13632 14011 14265
> 14366 14412 14465 14606 14743 14764 14803 14893 15009 16924 17011 17361 1
> 7506 17676 18440 18509 18565 18806 18834 18988 19019 19262 19444 19541
> 19568 19577 19648 19831 20001 20231 22504 24604]
> NEXT_HOP: 64.211.147.146
> AGGREGATOR: AS23089 157.130.101.226
> COMMUNITY: 3549:2256 3549:30840
> ANNOUNCE
>   65.215.97.0/24
> 
>