RE: CenturyLink RCA?

["Naslund, Steve" <SNaslund () medline com>]

A note for the guys hanging on to those POTS lines…It won’t really help.  One of our sites in Dubuque Iowa had ten 
CenturyLink PRIs (they are the LEC there) homed off of a 5ESS switch.  These all were unable to process calls during 
the CenturyLink problem.  The ISDN messaging returned indicated that the CL phone switch had no routes.  This tells me 
that either their inter-switch trunking or SS7 network or both are being transported over the same optical network as 
the Internet services.  So, even if your local line is POTS or traditional TDM it won’t matter if all of their 
transport is dependent on the IP world.

Looking at the Reddit comments on the Infinera devices being a problem, that makes more sense because that device blurs 
the line between optical mux and IP enabled devices with its Ethernet mapping functions.  One advantage of the pure 
optical mux is that it does not need, care, or understand L2 and L3 network protocols and are largely unaffected by 
those layers.  Convergence in devices moving across more network layers exposes it to more potential bugs.  Convergence 
can easily lead to more single points of failure and the traffic capacity of these devices kind of encourages carriers 
to put more stuff in one basket than they traditionally did.  I understand the motivation to build a single high speed 
IP centric backbone but it makes everything dependent on that backbone.

Steven Naslund
Chicago IL