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Re: Frame Relay encap vis-a-vis point-to-point at UUNET

  • From: Mark Tripod
  • Date: Tue Sep 22 14:15:50 1998


The story that you were told jives with what I was told many moons ago
by UUNet when I ordered lines for my previous employer. The need for
frame relay encapsulation is not necessary since the Cascade (Ascend)
9000 supports PPP to frame relay translation.

At Pacific Bell Internet we turned up all dedicated ports on PPP even
though they terminated on our 9000 and the customer was never the wiser.
I guess UUNet likes to explain to each and every customer why they are
using FR encap instead of PPP.

The short answer to your question is, no. There is basically no
difference between FR and PPP as far as performance of your line goes.

Mark Tripod
Senior Backbone Engineer
Exodus Communications

Barry L James wrote:
> Hey all,
>         We just got a third T1, this time through UUNet and when I looked
> at their router configuration I got a little surprise.  We ordered a
> point-to-point circuit that is being terminated at their detroit POP.  The
> configuration, however, sets up the line as a frame relay encap on a
> sub-interface (on a Cisco, of course :).  When I talked to my UUNet rep he
> advised that this was the way "every large ISP did it" which I knew wasn't
> exactly true since our MCI and AT&T (just recently transitioned from the
> BBN backbone to the AT&T network) does not use this configuration.  He
> insisted that it was still a point to point and that the frame relay
> encapsulation was used to enhance the connection.
> Well, I had him grab an engineer (he was an SE) that could possibly
> explain it better to me (since the SE said F/R was used to decrease RIP
> broadcasts across their backbone) and the engineer said this (basically):
> the circuit is terminated in a cascade 9000 f/r switch (used for port
> density) which went to a HSSI interface in a Cisco 7xxx series router
> which connected directly to their ATM network.  Therefore, the f/r encaps
> were needed to speak with the cascade.  The engineer advised we had a full
> CIR and would not suffer any bandwidth loss from using f/r encap.
> Now, I guess my question is: am I getting sold the brooklyn bridge here?
> I mean, not that I wouldn't like to *own* the brooklyn bridge (well, I'd
> rather have the triboro or the washington, but anyway...).  Is this f/r
> encap going have any adverse affect on the quality of this connection
> (assuming that this is *NOT* a point-to-point into a frame cloud) or am I
> getting shoveled a load of copralite?
> Thanks!
> Barry
> Barry L James           | Mikrotec Internet Services, Inc (AS3801)
> Director R & D          | 1001 Winchester Rd
>          | Lexington KY 40505
>     | 606/266.5925   800/875.5095
> Member AAAI, IEEE # 40277528
> ---
> Man will occasionally stumble over the truth, but most of the time he
> will pick himself up and continue on. -- Winston Churchill

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