BGP Intra-AS and Route Reflection
Since BGP is designed to be an overlay protocol, it doesn’t really have good mechanisms for carrying routes within an autonomous system. In this video, I’m discussing some of the techniques developed to carry routes within an AS, including route reflectors.
Hedge 134: Ten Things
One of the many reasons engineers should work for a vendor, consulting company, or someone other than a single network operator at some point in their career is to develop a larger view of network operations. What are common ways of doing things? What are uncommon ways? In what ways is every network broken? Over time, if you see enough networks, you start seeing common themes and ideas. Just like history, networks might not always be the same, but the problems we all encounter often rhyme. Ken Celenza joins Tom Ammon, Eyvonne Sharp, and Russ White to discuss these common traits—ten things I know about your network.
On Building a Personal Brand
How do you balance loyalty to yourself and loyalty to the company you work for?
This might seem like an odd question, but it’s an important component of work/life balance many of us just don’t think about any longer because, as Pete Davis says in Dedicated, we live in a world of infinite browsing. We’re afraid of sticking to one thing because it might reduce our future options. If we dedicate ourselves to something bigger than ourselves, then we might lose control of our direction. In particular, we should not dedicate ourselves to any single company, especially for too long.
Hedge 133: Brooks Westfield and Multifactor Testing
Multi-factor testing is one of the most important jobs a vendor takes on—and one of the most underrated. Testing across all possible configurations and use cases is nearly impossible. Brooks Westbrook joins Tom Ammon and Russ White on this episode of the Hedge to talk about the complexity of multi-factor testing and some of the consequences of that complexity.
Revisiting BGP Convergence
My video on BGP convergence elicited a lot of . . . feedback, mainly concerning the difference between convergence in a data center fabric and convergence in the DFZ. Let’s begin here—BGP hunt and the impact of the MRAI are very real in the DFZ. Withdrawing a route can take several minutes.
What about the much more controlled environment of a data center fabric?
Several folks pointed out that the MRAI is often set to 0 in DC fabrics (and many implementations by default). Further, almost all implementations will use an MRAI of 0 for the first received update, holding the second and subsequent advertisements by the MRAI. Several folks also pointed out that all the paths through a DC fabric are the same length, so the second part of the equation is also very small.
These are good points—how do they impact BGP convergence? Let’s use the network below, a small slice of a five-stage butterfly fabric, to think it through. Assume every router is in a different AS, so all the peering sessions are eBGP.
Hedge 132: DNS Complexity and the DNAME
We all intuitively know the DNS is complex—and becoming more complex over time. Describing just how complex, however, is difficult. Siva Kesava and Ryan Beckett just published a research paper taking on the task of describing DNS complexity, particularly in light of the new DNAME record type. It turns out its complex enough that you can no longer really validate zone files.
How BGP Really Converges
This lesson in Russ White’s BGP course gets into withdrawing a route, MRAI time, implicit withdraws, BGP Hunt, graceful restart, and other topics.
Hedge 131: Easier for the Computer or the Person?
One of the mainstays of scripting—and now network management—are increasingly focused on making things “easier” for the human operator. Does this focus on making things “easier” for the operator produce a better experience, though? Or does it create frustration as humans try to “outguess” the computer’s programming and process? Join Tom Ammon and Russ White as they discuss the problems with scripting, automation, and ease-of-use.
Hedge 130: The Importance of Network Inventories
Inventories are generally hard, and hence don’t tend to be where you’d like to spend your time. The importance of having a good inventory, however, can hardly be overstated. Malcom Booden joins Tom Ammon and Russ White to talk about the importance of inventories and inventory ideas.
