Category: BGP

The BGP-based SDN Solutions webinar triggered another interesting question from one the attendees:

It seems like the BGP route reflector functionality can be implemented as a Virtual Machine. Will a VM have enough resources to meet the requirements of a RR?

Short answer: Yes.

One of my ExpertExpress engagements focused on BGP route maps and setting BGP attributes based on BGP communities, so I wanted to brush up my RouteMapFoo before the online session.

Here are a few (not-so-unexpected) results gathered from IOSv release 15.5(3)M.

One of my readers sent me this observation while reviewing my BGP-Based SDN Solutions webinar:

I am a bit surprised the SDN controller can actually be so lightweight.

Well, that's the benefit of augmenting an existing well-developed ecosystem instead of reinventing the wheel and reimplementing every single bit of functionality we had to develop to make networks work throughout the last 5 decades.

Continuing our routing-on-hosts discussions, Enno Rey (of the Troopers and IPv6 security fame) made another interesting remark “years ago we were so happy when we finally got rid of gated on Solaris” and I countered with “there are still people who fondly remember the days of running gated on Solaris” because it’s a nice solution to host-to-network multihoming problem.

I had a great chat with Enno Rey the morning before Troopers 2016 started in which he he made an interesting remark:

I disagree with your idea of running BGP on servers because I think sysadmins shouldn’t be involved with routing.

As (almost) always, it turned out that we were still in violent agreement ;)

Salman left an interesting comment on my Running BGP on Servers blog post:

My prior counterparts thought running OSPF on Mainframes was a good idea. Then we had a routing blackhole due to misconfiguration on the server. Twice! The main issue was the Mainframe admins lack of networking/OSPF knowledge.

Well, there’s a reason OSPF is called Interior Routing Protocol.

Daniel Dib wrote a great series of BGP-related blog posts well worth reading.

• BGP convergence
• BGP confederations
• Inter-AS MPLS/VPN

Daniel is looking at BGP from the WAN/ISP perspective; if you want to know more about running BGP in the data center, watch the videos I recorded with Dinesh Dutt a few days ago.

The featured webinar in March 2016 is the Leaf-and-Spine Designs update to the Leaf-and-Spine Fabrics webinar, and in the featured videos (the ones marked with a star) you'll find in-depth explanation of BGP features available in Cumulus Linux, including a cool trick that allows you to run EBGP sessions across unnumbered interfaces.

After explaining the basics of BGP-LS and PCEP, and a quick deep dive into BGP-LS, Julian Lucek focused on the second topic of his excellent webinar and described the details of Path Computation Element Protocol (PCEP).

My good friend Tiziano Tofoni (the organizer of wonderful autumn seminars in Rome) sent me these questions after attending the BGP-LS and PCEP Deep Dive webinar, starting with:

Are there real use cases for BGP-LS and PCEP? Are they really useful? Personally I do not think they will ever be used by ISP in their (large) networks.

There are some ISPs that actually care about the network utilization on their expensive long-distance links.

After explaining why you’d want to use BGP-LS and PCEP in your network, Julian Lucek did a quick deep dive into the intricacies of BGP-LS, including printouts relating BGP-LS updates to IS-IS topology database.

This part of the PCEP/BGP-LS webinar is already public, to watch the rest of it fill in a short form on the webinar description page.

Mr. A. Anonymous left this comment on my BGP in the data centers blog post:

BGP is starting to penetrate into servers as well. What are your thoughts on having BGP running from the servers themselves?

Finally some people got it. Also, welcome back to the '90s (see also RFC 1925 section 2.11).

One of the comments added to my Using BGP in Data Centers blog post said:

With symmetric fabric… does it make sense for a node to know every bit of fabric info or is reachability information sufficient?

Let’s ignore for the moment that large non-redundant layer-3 fabrics where BGP-in-Data-Center movement started don’t need more than endpoint reachability information, and focus on a bigger issue: is knowledge of network topology (as provided by OSPF and not by BGP) beneficial?

While the large data centers increasingly use BGP as the routing protocol within their fabrics, the enterprise engineers tend to shy away from that idea because they think BGP is too complex/scary/hard-to-configure/obsolete/unknown/whatever.

It’s time to fix that.

Julian Lucek did a fantastic job describing how NorthStar controller uses BGP-LS and PCEP, so I asked him whether he’d be willing to do a deep dive on these two topics. He gracefully agreed, and the results are already online.