SDN Internet Router (sir)

Mike Hammett nanog at
Tue Jan 10 21:18:05 UTC 2023

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 at> 
To: "Mike Hammett" <nanog at> 
Cc: "NANOG" <nanog at>, "Forrest Christian (List Account)" <lists at> 
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 at > 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 ;) 


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