nanog mailing list archives

Re: Curiosity about AS3356 L3/CenturyLink network resiliency (in general)


From: Mark Tinka <mark.tinka () seacom mu>
Date: Thu, 17 May 2018 00:39:22 +0200



On 16/May/18 18:59, David Hubbard wrote:

I’m curious if anyone who’s used 3356 for transit has found shortcomings in how their peering and redundancy is 
configured, or what a normal expectation to have is.  The Tampa Bay market has been completely down for 3356 IP 
services twice so far this year, each for what I’d consider an unacceptable period of time (many hours).  I’m 
learning that the entire market is served by just two fiber routes, through cities hundreds of miles away in either 
direction.  So, basically two fiber cuts, potentially 1000+ miles apart, takes the entire region down.  The most 
recent occurrence was a week or so ago when a Miami-area cut and an Orange, Texas cut (1287 driving miles apart) took 
IP services down for hours.  It did not take point to point circuits to out of market locations down, so that 
suggests they even have the ability to be more redundant and simply choose not to.

I feel like it’s not unreasonable to expect more redundancy, or a much smaller attack surface given a disgruntled 
lineman who knows the routes could take an entire region down with a planned cut four states apart.  Maybe other 
regions are better designed?  Or are my expectations unreasonable?  I carry three peers in that market, so it hasn’t 
been outage-causing, but I use 3356 in other markets too, and have plans for more, but it makes me wonder if I just 
haven't had the pleasure of similar outages elsewhere yet and I should factor that expectation into the design.  It 
creates a problem for me in one location where I can only get them and Cogent, since Cogent can't be relied on for 
IPv6 service, which I need.

Are Century Link your only option?

Mark.


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