Re: SDN Internet Router (sir)

[Mike Hammett <nanog () ics-il net>]

It depends on the number of these other routers. For a last-mile provider, you may have hundreds or even thousands of 
POPs that only connect to other parts of your network and customers. 




----- 
Mike Hammett 
Intelligent Computing Solutions 

Midwest Internet Exchange 

The Brothers WISP 

----- Original Message -----

From: "Matthew Walster" <matthew () walster org> 
To: "Mike Hammett" <nanog () ics-il net> 
Cc: "NANOG" <nanog () nanog org>, "Forrest Christian (List Account)" <lists () packetflux com> 
Sent: Friday, January 6, 2023 10:10:56 AM 
Subject: Re: SDN Internet Router (sir) 







On Fri, 6 Jan 2023, 18:38 Mike Hammett, < nanog () ics-il net > wrote: 




I suspect it always will have value, whether it's peering routers, POP routers, multi-homed customer routers, etc. 




Indeed. It's not "clean" but it is an acceptable tradeoff if you know what you're doing, and how traffic sloshes around 
etc. 


I wrote a tool once that took a number of BGP feeds and aggregated the prefixes based on the next-hop values, which was 
*amazingly* good at reducing FIB sizes, but consumed so much CPU and memory, not to mention the latency of updates 
during any sizeable churn event, that it proved less useful than just precomputing based on historical traffic flows 
and updating the lists semi-frequently. 


The idea of Juniper's EPE etc is very attractive, and largely matches what I had done back then, but does it with a lot 
more finesse. Ultimately, it's a tradeoff between CapEx of the high FIB router and the OpEx of the engineers who have 
to maintain the often hacky solution ;) 




M