[1084] in North American Network Operators' Group
Re: Links on the blink - reprise
daemon@ATHENA.MIT.EDU (Paul Ferguson)
Sat Nov 18 10:34:32 1995
Date: Sat, 18 Nov 1995 10:25:08 -0500
To: "Mike O'Dell" <mo@uunet.uu.net>
From: Paul Ferguson <pferguso@cisco.com>
Cc: smd@sprint.net, cook@cookreport.com, nanog@merit.edu
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
