North American Network Operators Group

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Re: Links on the blink - reprise

  • From: Paul Ferguson
  • Date: Sat Nov 18 10:58:42 1995

At 07:30 AM 11/18/95 -0500, Mike O'Dell wrote:

>don't confuse the link encoding with back-haul design

Don't confuse backhaul design with excessively high concentrations
of PVCs, grossly oversubscribed in ratio of aggragate ingress bandwidth.

If you don't drop the bits on ingress, you at least stand a fighting 
chance of getting them (the bits) onto the backbone in the first place.


>if the network is deeply over-subscribed, you will drop packets.
>the only question is "where?"

Where indeed.

>whether the link uses F/R-1490 framing or cisco HDLC doesn't change

This has nothing at all to do with it. Regardless of the frame-relay
encapsulation, the fact that one can oversubscribe at ingress exists
and lends itself to what Vadim calls 'too may points of indirection'.
A private line only has two end-points (let's not discuss imuxes).

The possibility of sloppy or careless engineering is just a tad
higher when building frame-relay networks. This does not mean that
sloppiness can't be avaoided; it certainly can.

Just a thought,

- paul