lukasz.bromirski.net

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4B ASNs, RIPE and IOS

during previous PLNOG we’ve had a broad discussion about apocalyptic vision of depleting IPv4 address space and 2-byte ASN space.

some time ago Cisco IOS 12.4(24)T was released, and it brings 4-byte ASN feature for ISR (1800/2800/3800) and 7200 routers. so if you’re using Cisco gear, you can request 4 byte ASN using RIPE form, and then advertising it properly (starting from 1st of January, 2009 RIPE will by default hand out 4 byte ASNs).

i’m taking a peek into the global routing tables from time to time, while preparing for CONFidence presentation.

yesterday, after upgrade of one of my routers to 12.4(24)T, I’ve found out two interesting gems. here you can find nicely built list of Polish ASNs, and below you can find BGP prefix 91.212.5.0/24 that belongs to AS 3.41 (i’m not sure however, if the ASN using it is running on Cisco ;) ):

sh ip bgp regexp _3\.41$
BGP table version is 847600, local router ID is x.x.x.x
Status codes: s suppressed, d damped, h history, * valid,
> best, i - internal, r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete

Network            Next Hop  Metric LocPrf Weight Path
* i91.212.5.0/24   x.x.x.x     0    100    0      5617 12968 3.41 i
*>                 y.y.y.y                 0      12741 20960 3.41 i

greetings to happy owner :)


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