North American Network Operators Group

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Re: Statistical Games Providers Play (RE: availability and resiliency)

  • From: Dave Cooper
  • Date: Sun Oct 01 20:51:50 2000


> If you look at network backbones, almost everyone uses the same vendors,
> supplying essentially the same equipment, and nearly the same network
> design.  So why would different providers have different availability
> numbers?  Is it just an accident of the statistical series, some providers
> had their failures earlier but everyone will end up the same in Year Infinity?
> Or are there real differences, besides price, between providers?

While most backbones are running similar equipment, the service contract
arrangements with vendors are probably across the board.  When talking about
edge (customer aggregation) devices and not the core, there are some
that spare every type of card in every single hub, some who declare spare
centers that are in geographic proximity to many hubs, there are
some who pay Vendor X some $$ to have X hour response to RMAs and 
there are others who rely on boilerplate RMA procedures.  It is 
surprising how much these factors play in restoral times on edge 
devices and affect MTTR.  On top of that.. a little brains in the NOC 
along with decent documentation on spares and resources is another factor
which can affect that MTTR.  The core and backbone should always
have redundancy built in (both network and hardware) and should continue
to provide some level of service should a failure occur -- no matter what
the ultimate design is.  But like Vijay said, designing the netowrk and 
reducing the number of dependencies (whether protocol, hardware or backbone)
will also decrease MTTR.