BGP prefix filter list

Mike Hammett nanog at
Wed May 15 18:51:07 UTC 2019

I wouldn't call it shaming the vendor. There are a ton of platforms out there by nearly every vendor that can't accommodate modern table sizes. 

Mike Hammett 
Intelligent Computing Solutions 


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

From: "Baldur Norddahl" <baldur.norddahl at> 
To: nanog at 
Sent: Wednesday, May 15, 2019 1:47:24 PM 
Subject: Re: BGP prefix filter list 

My purpose is not to shame the vendor, but anyway these are ZTE M6000. We are currently planing to implement Juniper MX204 instead, but not because of this incident. We just ran out of bandwidth and brand new MX204 are cheaper than 100G capable shelves for the old platform. 



On Wed, May 15, 2019 at 8:42 PM < mike.lyon at > wrote: 

Hello Baldur, 

What routers are you running? 


On May 15, 2019, at 11:22, Baldur Norddahl < baldur.norddahl at > wrote: 



On Wed, May 15, 2019 at 3:56 PM Mike Hammett < nanog at > wrote: 


What is the most common platform people are using with such limitations? How long ago was it deprecated? 

We are a small network with approx 10k customers and two core routers. The routers are advertised as 2 million FIB and 10 million RIB. 

This morning at about 2 AM CET our iBGP session between the two core routers started flapping every 5 minutes. This is how long it takes to exchange the full table between the routers. The eBGP sessions to our transits were stable and never went down. 

The iBGP session is a MPLS multiprotocol BGP session that exhanges IPv4, IPv6 and VRF in a single session. 

We are working closely together with another ISP that have the same routers. His network went down as well. 

Nothing would help until I culled the majority of the IPv6 routes by installing a default IPv6 route together with a filter, that drops every IPv6 route received on our transits. After that I could not make any more experimentation. Need to have a maintenance window during the night. 

These routers have shared IPv4 and IPv6 memory space. My theory is that the combined prefix numbers is causing the problem. But it could also be some IPv6 prefix first seen this night, that triggers a bug. Or something else. 





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