Whats so difficult about ISSU

Mon Nov 12 07:29:59 UTC 2012

On Mon, 12 Nov 2012, Bryan Fields wrote:

> And they only have to process maybe 2mbit/s of control traffic during 
> busy hour.  The rest is handled by dedicated hardware/ASIC's.  Each one 
> has a fully redundant hardware circuit pack and a bunch of monitoring to 
> switch over in case one fails.

I'd imagine it's also because some are written in a language especially 
designed for the task.

http://en.wikipedia.org/wiki/Erlang_(programming_language)

"... It supports hot swapping, so that code can be changed without 
stopping a system.[2]"

I've been told some people are doing routing control plane implementations 
in erlang just because of these features, but I'd imagine there is a 
hurdle getting enough programmers who are experienced in the language.

-- 
Mikael Abrahamsson    email: swmike at swm.pp.se