North American Network Operators Group

Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical

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
>that.
>


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