Two BGP peering sessions on single Comcast Fiber Connection?

Mike Hammett nanog at
Mon Oct 17 12:30:38 UTC 2016

It really seems like it's a grave oversight to *NOT* support multiple BGP sessions. I drop to two routers for that same reason, I can do maintenance on one, while the other carries traffic. 

Mike Hammett 
Intelligent Computing Solutions 


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

From: "Mike Poublon" <mpoublon at> 
To: "rar" <rar at>, nanog at 
Sent: Thursday, October 13, 2016 2:04:29 PM 
Subject: Re: Two BGP peering sessions on single Comcast Fiber Connection? 

I started a thread around the same topic back on 10/16 of 2014. A 
Comcast engineer (who ultimately spoke to the national product manager) 
came back after discussing and said the same thing "We don't support 
that". I got a slightly longer explanation of: 


In a nutshell, when we design a product we do it to accommodate the most 
typical customer cases. 
Given that the design includes a single fiber path and thus the fiber 
path and device that terminates on either end each are a single point of 
failure, adding extra BGP sessions doesn’t seem to add value in the 
typical failure scenarios. In order to achieve the simplest and most 
scalable solution to address the market, we rely on narrowing the 
possible combinations of parameters. 


I explained to them that their interpretation prevents me from being 
able to do concurrent maintenance on my side (single router 
reboot/upgrade, etc). Never got anywhere with it though. 

I'm still interested in having this set up, but have given up on it ever 
really coming to reality. Luckily ALL of my other providers were more 
than happy to set up an extra session. 

If anyone from Comcast is listening, there is customer demand for this. 
It's not about making it better for Comcast, it's about allowing 
customers to have more flexibility. 

Mike Poublon 

/Senior Datacenter Network Engineer/ 

*Secant Technologies* 

6395 Technology Ave. Suite A 

Kalamazoo, MI 49009 

On 10/13/2016 1:48 PM, rar wrote: 
> After a many month wait, we were ready to turn up our BGP peering sessions on a new Comcast fiber connection. 
> With our other providers (Level 3 and Verizon) we have edge routers that directly connect between the provider's on premise connection and our primary and a backup core routers. Each core router has a multihop BGP session with the provider's BGP router. The goal is to keep the single BGP router from being a single point of failure. 
> Comcast said they could not support two separate BGP peering sessions on the same circuit. Does anyone have any counter examples? We used to have this setup with Comcast 5+ years ago, but now they say they can't support it. 
> Bob Roswell 
> broswell at<mailto:broswell at> 
> 410-771-5544 ext 4336 
> Computer Museum Highlights<> 

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