From: Mark Tashiro (Mtashiro@PRESIDIO.com)
Date: Wed Mar 05 2003 - 22:38:37 GMT-3
If you look at the data sheet for any of the routers there is a max
forwarding rate that the router can process. For example a 1751 that is
process switching can only forward at a rate of .7 Mbps, CEF or fast
switched is around 4M bps. If buffers are exceeded traffic will drop. You
can look at the quick reference sheets to see what the router performance
is.
This can definately be an issue and one we have seen in the past.
-Mark
-----Original Message-----
From: Sam Munzani
To: ccielab@groupstudy.com
Sent: 3/5/2003 10:50 AM
Subject: At what percentage of T1 utilization you should see performance
degrade?
Hi,
Today we got in to a debate about T1 saturation and performance
degradation.
Below is 2 different opinions from my self and other engineer.
What I say.
T1 is a full duplex mechanism. So until it hits 100% utilization on it's
Serial(Full T1) interface it will forward to packet and no packet drop
will
happen. Only the time it will do a queue drop is when the traffic bursts
above
100%. This queue drop is because of Serial interface short on forwarding
buffers. Same behavior will happen on inbound. Only the time this would
be a
bottleneck is if router CPU is a bottleneck. This is on 3640 with Fast
switching turned on. I am assuming 3640 can handle more than 1 T1
bandwidth.
The other engineer's opinion.
3640 supports only 75000 pps with 64 bytes packets. His opinion is, your
users
will see performance problems even before T1 is hitting 100%(aroung 70
to
80%).
Any opinions with enough supporting proofs are most welcome.
Regards,
Sam Munzani
CCIE # 6479(R&S, Security)
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