nanog mailing list archives
Re: BGP prefix filter list
From: i3D.net - Martijn Schmidt <martijnschmidt () i3d net>
Date: Mon, 20 May 2019 22:23:30 +0000
Brocade (now Extreme) does this on their SLX platform to market 1M FIB boxes as 1.3M FIB boxes after compression. We went with the Juniper MX platform instead, the relatively small FIB size on the SLX being one of the main sticking points for me personally. Nowadays there are also some SLX models with a larger FIB, which don't need compression algorithms to accommodate the routing table growth for a couple of years. Best regards, Martijn On 20 May 2019 23:05:45 BST, William Herrin <bill () herrin us> wrote:
On Fri, May 17, 2019 at 9:06 AM Baldur Norddahl <baldur.norddahl () gmail com> wrote:Think about this way to save at least half the size of the FIB withtwotransit providers: Find out which provider has the most prefixesgoingtheir way. Make a default to them and a route-map that drops everyroute.For the other provider, keep only the routes where they have better routing. This way you only use FIB space for the smaller provider. Everything else goes by default through the larger provider.Hi Baldur, The technique you describe was one variant of FIB Compression. It got some attention around 8 years ago on the IRTF Routing Research Group and some more attention about 5 years ago when several researchers fleshed out the possible algorithms and projected gains. As I recall they found a 30% to 60% reduction in FIB use depending on which algorithm was chosen, how many peers you had, etc. As far as I know there are no production implementations. Likely the extra complexity needed to process RIB updates in to FIB updates outweighs the cost of simply adding more TCAM. Another down side is that you lose the implicit discard default route, which means that routing loops become possible. Regards, Bill Herrin
Current thread:
- Re: BGP prefix filter list / BGP hijacks, different type, (continued)
- Re: BGP prefix filter list / BGP hijacks, different type Christopher Morrow (May 17)
- Re: BGP prefix filter list Radu-Adrian Feurdean (May 17)
- Re: BGP prefix filter list Blake Hudson (May 17)
- Re: BGP prefix filter list Baldur Norddahl (May 17)
- Re: BGP prefix filter list Blake Hudson (May 17)
- Re: BGP prefix filter list Baldur Norddahl (May 17)
- Re: BGP prefix filter list Blake Hudson (May 17)
- Re: BGP prefix filter list Baldur Norddahl (May 18)
- Re: BGP prefix filter list Blake Hudson (May 20)
- Re: BGP prefix filter list William Herrin (May 20)
- Re: BGP prefix filter list i3D . net - Martijn Schmidt (May 20)
- Re: BGP prefix filter list Seth Mattinen (May 20)
- Re: BGP prefix filter list William Herrin (May 20)
- Message not available
- Re: BGP prefix filter list John Kristoff (May 20)
- Re: BGP prefix filter list Seth Mattinen (May 20)
- Re: BGP prefix filter list Ca By (May 20)
- Re: BGP prefix filter list Alejandro Acosta (May 21)
- Re: BGP prefix filter list Tom Beecher (May 22)
- Re: BGP prefix filter list Alejandro Acosta (May 22)
- Re: BGP prefix filter list Sabri Berisha (May 22)
- Re: BGP prefix filter list Ross Tajvar (May 22)