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Re: Agenda for next NANOG

  • From: Curtis Villamizar
  • Date: Sat Aug 31 01:23:14 1996

In message <>, Michael 
Dillon writes:

> And even if an ISP monitors their router stats and sees peak traffic at
> around 60% of a T1 they could still have congestion problems elsewhere in
> their network such as their Ethernet or lines to POP's. All of this stuff
> contributes to public perceptions of a slow Internet and somebody has to
> take the first step to do end-to-end testing and point out where these
> trouble spots really are.

I agree with you completely on this.  I was talking about loss in T3
(and one OC3 that isn't all OC3) backbones.  A congested serial link
will drop packets but if it is the only bottleneck TCP will usually
not push anything through the congested link twice.  (Fast retransmit
and fast recovery just retransmit what never went through the
bottleneck in the first place).  When you can't get anything anywhere
near 28.8 on your 28.8, you get upset (or you don't get 56k on your
56k or T1 on your T1s).


ps- I've copied as much as 600 MB and got about 160 KB/sec (1/2 T1)
from Ann Arbor through the Elmsford T1 at mid day.  That's reasonable
performance.  Not everyone can do that on their provider's backbone.
Try it sometime.  (Might want to go with less than 600 MB).  I didn't
tweak the code and open the TCP window or it might have been more (but
folks in Elmsford might be slightly unhappy, even though it was TCP).
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