External BGP Controller for L3 Switch BGP routing

Tue Jan 17 16:31:10 UTC 2017

Cisco and Arista are both able to squeeze a current full Internet table into the base space on their Jericho boxes, using the right space partitioning.   Cisco added this in 6.1.2  without anything in the release notes, but you’ll notice they bumped the datasheet spec on the base 5502 to 1M FIB now where it used to be 256K.    It works with the standard Internet table, but may not work if you have a ton of routes with lengths that do not work well with how the memory is carved up.   Of course Jericho is more expensive than Trident.  

Phil 

-----Original Message-----
From: NANOG <nanog-bounces at nanog.org> on behalf of joel jaeggli <joelja at bogus.com>
Date: Tuesday, January 17, 2017 at 00:22
To: Yucong Sun <sunyucong at gmail.com>, Tore Anderson <tore at fud.no>, Saku Ytti <saku at ytti.fi>
Cc: nanog list <nanog at nanog.org>
Subject: Re: External BGP Controller for L3 Switch BGP routing

    On 1/15/17 11:00 PM, Yucong Sun wrote:
    > In my setup, I use an BIRD instance to combine multiple internet full
    > tables,  i use some filter to generate some override route to send to my L3
    > switch to do routing.  The L3 switch is configured with the default route
    > to the main transit provider , if BIRD is down, the route would be
    > unoptimized, but everything else remain operable until i fixed that BIRD
    > instance.
    > 
    > I've asked around about why there isn't a L3 switch capable of handling
    > full tables, I really don't understand the difference/logic behind it.

    In practice there are several merchant silicon implmentations that
    support the addition of external tcams. building them accordingly
    increases the COGS and and various performance and packaging limitions.

    arista 7280r and cisco ncs5500 are broadcom jericho based devices that
    are packaged  accordingly.