AS-Path - ORF Draft

Mike Hammett nanog at
Mon Oct 23 14:56:43 CST 2017

I was looking at using arouteserver to automate my prefix filter generation. I'll do a feature request over there. 

Mike Hammett 
Intelligent Computing Solutions 

Midwest Internet Exchange 

The Brothers WISP 

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

From: "Job Snijders" <job at> 
To: "Mike Hammett" <nanog at> 
Cc: "NANOG" <nanog at> 
Sent: Monday, October 23, 2017 8:24:51 AM 
Subject: Re: AS-Path - ORF Draft 

On Mon, Oct 23, 2017 at 07:53:03AM -0500, Mike Hammett wrote: 
> Should I assume that invigorating traction for a 17 year old draft is 
> rather difficult? 

John Heasley told me that a fundamental difficulty here is that not 
every implementation uses the same style/type of regular expressions. 
Unifying this behaviour across vendors will require a lot of pull. 

> It is my understanding that Network B does wish to accept Network A's 
> prefixes elsewhere, just not here. I believe that specifying the block 
> via IRR would be universal and probably not wanted. 

You can make it IX specific by using an old proposal called 'RPSL VIA'. 
Look for "The script supports most of the IETF snijders-rpsl-via draft 

> Some of my fellow IX operators have advised me to avoid doing manual 
> filtering for a variety of reasons. 

Yes, they are right. The moment the route server operator introduces 
hacks like that, the affected participants may forget those hacks 
existed over time. 

On the flip side, if Network B can't filter out the announcements, or 
insists on using a pre-policy maximum prefix limit - and Network A 
refuses to add a suppression community to their announcements to the 
route server (maybe because they want to cookie stamp all those 
configs), what can you (as person in the middle) do? 

If both network A and network B refuse to cooperate / coordinate, it 
somewhat dilutes the value of the route server to participants C/D/E 
because network B keeps flapping. 

> Which IXes have a web portal for that? Offlist is fine. I'd like to 
> see that and talk to them about their implementation. 

I believe NL-IX ( and VIX ( are 
example IXPs that have this. There are probably a bunch more that offer 
this type of feature. 

Kind regards, 


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