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

Jon Lewis jlewis at inorganic5.fdt.net
Tue Sep 22 23:43:04 UTC 1998


On Mon, 21 Sep 1998, Barry L James wrote:

> 	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

This is what we ended up with when we moved our UUNet T1 from their Miami
POP to their JAX POP.  Coincidentally, this is also when our service from
UUNet went from flawless to sh!t.  My understanding is that we had a full
point to point T1 terminated (possibly as part of some much bigger pipe)
in Cascade Frame Relay switch, which then had a HSSI connection into a
Cisco 75XX router.  We were able to pull full T1 bandwidth over the
line...but UUNet had chronic problems with the Cascade switch, we had lots
of downtime that was never explained, and it seemed to perform
particularly badly when faced with more traffic than could be handled by
our T1.  Smurf attacks would apparently cause the cascade to reset our T1
at regular <1s intervals, such that during an attack, we'd get a burst of
traffic, then absolutely nothing, then a burst of traffic. 

> 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

Sounds like what we had.

> 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.

Probably not...but do they know how to properly run the Cascades yet?  We
had very serious reliability problems when we were on UUNet.

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