nanog mailing list archives

Re: Netcom Outage (Was: My InfoWorld Column About NANOG)


From: "Jim J. Steinhard" <jjs () sprint net>
Date: Tue, 25 Jun 1996 15:22:16 -0400 (EDT)

Michael,
 
On Fri, 21 Jun 1996, Michael Dillon wrote:

... 
But to me, backhoes are the most interesting failure mode. For one,I
don't think that backhoe problems can be eliminated

I don't know about total elimination but we're working on it.  Sprint is  
currently deploying 4-fiber bi-directional SONET rings that will
cause fiber cuts to go virtually unnoticed.  Circuits are switched to a
 protect channel in about 50 msec after a failure of the primary path.

   
 and I think that as
the physical mesh of fibre becomes more finely divided over the geography,
these incidents will increase. And I also don't know of anyone taking
action to protect against these events by building geographic redundancy
into their backbones. This may be partly because NSP's often don't have
any idea where the fibres lie and partly because they want to use a
specific infrastructure like SPRINT and its railway rights of way. The
incident in the Northeast where a backhoe cut a Wiltel(?) fibre bundle
that was carrying critical DS3's leased by all the NSP's in the region
points out how catastrophic this can be.
 
  Again, this may not be totally eliminated. However, we are working to 
provide as much physical path diversity as possible.

          Jim Steinhardt
      SprintLink Engineering 


Michael Dillon                                   ISP & Internet Consulting
Memra Software Inc.                                 Fax: +1-604-546-3049
http://www.memra.com                             E-mail: michael () memra com


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