Re: question about bgp incremental updates

[Mateusz Viste <nogs () border6 com>]

Hi,

I can think of two reasons for such behavior:

- one of the attributes of these routes changed suddenly, so they have 
been reannounced by your peer,
- you sent a 'route refresh' request to this peer, asking him to 
reannounce all his table.

Other than that, I don't see why a peer would resend lots of 
already-announced prefixes..

cheers,
Mateusz




On 08/04/2014 04:29 AM, Song Li wrote:
> Hi everyone,
>
> I have a question about bgp updates:
>
> BGP uses an incremental update strategy to conserve bandwidth and
> processing power.  That is, after initial exchange of complete routing
> information, a pair of BGP routers exchanges only the changes to that
> information. ( from RFC4274)
>
> According to this principle, if an AS suddenly announced a lot of
> updates (as below), can it be regarded as an anomaly such as BGP session
> reset? I wish to know if there are other reasons can result in this
> anomaly.
>
> Thanks!
>
> BGP4MP|04/23/14 13:05:12|A|216.218.252.164|6939|218.189.24.0/24|6939
> 15412 9304|IGP
> BGP4MP|04/23/14 13:05:12|A|216.218.252.164|6939|218.189.28.0/24|6939
> 15412 9304|IGP
> BGP4MP|04/23/14 13:05:12|A|216.218.252.164|6939|218.189.16.0/24|6939
> 15412 9304|IGP
> BGP4MP|04/23/14 13:05:12|A|216.218.252.164|6939|218.189.20.0/24|6939
> 15412 9304|IGP
> BGP4MP|04/23/14 13:05:12|A|216.218.252.164|6939|218.189.16.0/20|6939
> 15412 9304|IGP
> BGP4MP|04/23/14 13:05:12|A|216.218.252.164|6939|218.189.12.0/24|6939
> 15412 9304|IGP
> BGP4MP|04/23/14 13:05:12|A|216.218.252.164|6939|218.189.12.0/22|6939
> 15412 9304|IGP
> BGP4MP|04/23/14 13:05:12|A|216.218.252.164|6939|218.189.204.0/23|6939
> 4436 25973 9304|IGP
> BGP4MP|04/23/14 13:05:12|A|216.218.252.164|6939|218.189.208.0/21|6939
> 4436 25973 9304|IGP
> BGP4MP|04/23/14 13:05:12|A|216.218.252.164|6939|218.189.8.0/24|6939 4436
> 25973 9304|IGP
> BGP4MP|04/23/14 13:05:12|A|216.218.252.164|6939|202.1.32.0/20|6939 15412
> 9304|IGP
> BGP4MP|04/23/14 13:05:12|A|216.218.252.164|6939|218.189.204.0/23|6939
> 9304|IGP
> BGP4MP|04/23/14 13:05:12|A|216.218.252.164|6939|218.189.208.0/21|6939
> 9304|IGP
> BGP4MP|04/23/14 13:05:12|A|216.218.252.164|6939|218.189.24.0/24|6939
> 9304|IGP
> BGP4MP|04/23/14 13:05:12|A|216.218.252.164|6939|218.189.28.0/24|6939
> 9304|IGP
> BGP4MP|04/23/14 13:05:12|A|216.218.252.164|6939|218.189.16.0/24|6939
> 9304|IGP
> BGP4MP|04/23/14 13:05:12|A|216.218.252.164|6939|218.189.20.0/24|6939
> 9304|IGP
> BGP4MP|04/23/14 13:05:12|A|216.218.252.164|6939|218.189.16.0/20|6939
> 9304|IGP
> BGP4MP|04/23/14 13:05:12|A|216.218.252.164|6939|218.189.12.0/24|6939
> 9304|IGP
> BGP4MP|04/23/14 13:05:12|A|216.218.252.164|6939|218.189.12.0/22|6939
> 9304|IGP
> BGP4MP|04/23/14 13:05:12|A|216.218.252.164|6939|218.189.8.0/24|6939
> 9304|IGP
> BGP4MP|04/23/14 13:05:12|A|216.218.252.164|6939|202.1.32.0/20|6939 9304|IGP
> BGP4MP|04/23/14 13:05:12|A|216.218.252.164|6939|114.134.83.0/24|6939
> 3549 9304|IGP
> BGP4MP|04/23/14 13:05:12|A|216.218.252.164|6939|203.90.243.0/24|6939
> 15412 9304|IGP
> BGP4MP|04/23/14 13:05:12|A|216.218.252.164|6939|203.90.251.0/24|6939
> 15412 9304|IGP
> BGP4MP|04/23/14 13:05:12|A|216.218.252.164|6939|118.143.224.0/20|6939
> 15412 9304|IGP
> BGP4MP|04/23/14 13:05:12|A|216.218.252.164|6939|118.143.232.0/24|6939
> 15412 9304|IGP
> BGP4MP|04/23/14 13:05:12|A|216.218.252.164|6939|202.46.57.0/24|6939
> 15412 9304|IGP
> BGP4MP|04/23/14 13:05:12|A|216.218.252.164|6939|202.46.53.0/24|6939
> 15412 9304|IGP
> BGP4MP|04/23/14 13:05:12|A|216.218.252.164|6939|202.46.61.0/24|6939
> 15412 9304|IGP
> BGP4MP|04/23/14 13:05:12|A|216.218.252.164|6939|202.46.49.0/24|6939
> 15412 9304|IGP
> BGP4MP|04/23/14 13:05:12|A|216.218.252.164|6939|103.17.240.0/22|6939
> 15412 9304|IGP
> BGP4MP|04/23/14 13:05:12|A|216.218.252.164|6939|103.17.240.0/24|6939
> 15412 9304|IGP
> BGP4MP|04/23/14 13:05:12|A|216.218.252.164|6939|112.73.6.0/23|6939 15412
> 9304|IGP
> BGP4MP|04/23/14 13:05:13|A|216.218.252.164|6939|118.194.231.0/24|6939
> 3549 9304|IGP
> BGP4MP|04/23/14 13:05:13|A|216.218.252.164|6939|175.100.198.0/24|6939
> 3549 9304|IGP
> BGP4MP|04/23/14 13:05:13|A|216.218.252.164|6939|175.100.206.0/24|6939
> 15412 9304|IGP
> BGP4MP|04/23/14 13:05:13|A|216.218.252.164|6939|210.0.209.0/24|6939 4436
> 25973 9304|IGP
> BGP4MP|04/23/14 13:05:13|A|216.218.252.164|6939|210.3.0.0/22|6939 4436
> 25973 9304|IGP
> BGP4MP|04/23/14 13:05:13|A|216.218.252.164|6939|210.3.4.0/23|6939 4436
> 25973 9304|IGP
> BGP4MP|04/23/14 13:05:13|A|216.218.252.164|6939|103.227.207.0/24|6939
> 1299 3257 9304|IGP
> BGP4MP|04/23/14 13:05:13|A|216.218.252.164|6939|114.134.83.0/24|6939
> 9304|IGP
> BGP4MP|04/23/14 13:05:13|A|216.218.252.164|6939|203.90.243.0/24|6939
> 9304|IGP
> BGP4MP|04/23/14 13:05:13|A|216.218.252.164|6939|203.90.251.0/24|6939
> 9304|IGP
> BGP4MP|04/23/14 13:05:13|A|216.218.252.164|6939|118.143.224.0/20|6939
> 9304|IGP
> BGP4MP|04/23/14 13:05:13|A|216.218.252.164|6939|118.143.232.0/24|6939
> 9304|IGP
> BGP4MP|04/23/14 13:05:13|A|216.218.252.164|6939|202.46.57.0/24|6939
> 9304|IGP
> BGP4MP|04/23/14 13:05:13|A|216.218.252.164|6939|202.46.53.0/24|6939
> 9304|IGP
> BGP4MP|04/23/14 13:05:13|A|216.218.252.164|6939|202.46.61.0/24|6939
> 9304|IGP
> BGP4MP|04/23/14 13:05:13|A|216.218.252.164|6939|202.46.49.0/24|6939
> 9304|IGP
> BGP4MP|04/23/14 13:05:13|A|216.218.252.164|6939|103.17.240.0/22|6939
> 9304|IGP
> BGP4MP|04/23/14 13:05:13|A|216.218.252.164|6939|103.17.240.0/24|6939
> 9304|IGP
> BGP4MP|04/23/14 13:05:13|A|216.218.252.164|6939|112.73.6.0/23|6939 9304|IGP
> BGP4MP|04/23/14 13:05:13|A|216.218.252.164|6939|118.194.231.0/24|6939
> 9304|IGP
> BGP4MP|04/23/14 13:05:13|A|216.218.252.164|6939|175.100.206.0/24|6939
> 9304|IGP
> BGP4MP|04/23/14 13:05:13|A|216.218.252.164|6939|210.0.209.0/24|6939
> 9304|IGP