Hi, Goran, everyone --

On 23 Apr 2015, at 09:06, Goran Slavic <gsla...@sox.rs> wrote:

> at the mailing list and have an interest in downloading and implementing the 
> Euro-IX version of Quagga in our Internet exchange. My questions are simple:
> - Considering the time when the post is written (2012) - what is the current 
> status of the Euro-IX Quagga ?
> - Where can it be downloaded as a stable release / version ?

This email is a comment on using this software as a route-server, and not a 
comment on using this software as a RIB manager on a forwarding device - if 
you’re a reader from the future trying to understand about running this 
software on a router, then please bear this in mind.

There are three well known open source BGP implementations which are commonly 
used as a route-server - BIRD, Quagga, and OpenBGPd.  It is typical to 
configure them today in a way that has the route-server calculate a different 
RIB for every connected ASN on your exchange.  This is because it is also 
common to allow route-server users to filter (prevent their prefixes reaching) 
other participants.  Information about why this is important has been published 
in various presentations and papers at IX and operator events.

Calculating best-path for every participant becomes complex when you have a lot 
of participants, further when the number of prefixes on the exchange grows.  

OpenBGPd will stay up but take a very long time to process and forward 
announce/withdraw BGP messages.  On a ~100 ASN/participant/table system with 
~5000 prefixes, it can take anywhere up to an hour for a withdraw to be 
processed and forwarded which means your participants will get a route that is 
withdrawn for a long time and blackhole traffic at the exchange. It is 
therefore problematic to use this software on all but the smallest exchanges.  
It’s OK on small instances but does not scale.

Quagga’s vanilla build will fail to stay up with large numbers of tables and 
participants.  Chris Hall did an amazing job at making a build that was more 
prone to staying up and his build is doing a sterling job at LINX (alongside 
BIRD) but I understand that this source tree is no longer maintained and that 
the task of merging his stability fixes into the mainline or OSR 
(https://www.opensourcerouting.org) version is not a simple job and has not 
been done.  This gives me a serious concern about the future of this branch.

BIRD just doesn’t die, no matter what scale we seem to throw at it.  This thing 
just keeps flying.

We now have two (busy) BIRD instances at the LONAP exchange in London where 
most of our 150 exchange point members use the service.

Goran - SOX is a member of the Euro-IX association for exchange points and 
there is a private mailing list for members who operate route-servers.  There 
may be a greater concentration of route-server operators on that list so it’s 
probably worth continuing the discussion there?  You sign in to the website and 
visit https://www.euro-ix.net/mailing-list-archives to subscribe.

With best wishes,
Andy Davidson
(Relevant Hats: LONAP, IXLeeds, Euro-IX, IIX, NapAfrica)

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