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" <[email protected]> 
To: "Mike Hammett" <[email protected]> 
Cc: "NANOG" <[email protected]>, "Forrest Christian (List Account)" 
<[email protected]> 
Sent: Friday, January 6, 2023 10:10:56 AM 
Subject: Re: SDN Internet Router (sir) 







On Fri, 6 Jan 2023, 18:38 Mike Hammett, < [email protected] > 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 

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