From: Sam Munzani (sam@munzani.com)
Date: Thu Mar 06 2003 - 19:03:42 GMT-3
I am including those in T1 utilization. All I am looking is "sh int s0/0".
When it says load: 255/255 it's 100 saturated. 128/255 it's 50% saturated.
That saturation includes all your routing/keepalive traffic. My logic is, so
far it doesn't burst above 100% load, a packet will not get lost. It will
make it's way through on the other side of the circuit. It's different story
once it reaches on other end and remote network has congestion.
Sam
> Dont forget that the interface still must forward keepalives, routing
traffic and any other router generated traffic - that is part of what the
extra space is reserved for.
>
> ============================================================
> From: "OhioHondo" <ohiohondo@columbus.rr.com>
> Date: 2003/03/05 Wed PM 05:49:53 PST
> To: "Mike Schlenger" <mschlenger@meridianitsolutions.com>,
> "'Pratt,
> Jeremy'" <JPratt@coh.org>,
> "'Sam Munzani'" <sam@munzani.com>, <ccielab@groupstudy.com>
> Subject: RE: At what percentage of T1 utilization you should see
> performan ce degrade?
>
> Also note that if your utilization is at 70 or 80 percent, that is an
> average over a time period. You are probably peaking at 100% and using
your
> output buffers to accommodate peaks at over 100%.
>
> As a general rule I would take a good, indepth look at the circuit and
> interface (buffers, drops, etc.) at 70% and plan for additional bandwidth.
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
> Mike Schlenger
> Sent: Wednesday, March 05, 2003 4:08 PM
> To: 'Pratt, Jeremy'; 'Sam Munzani'; ccielab@groupstudy.com
> Subject: RE: At what percentage of T1 utilization you should see
> performan ce degrade?
>
>
> In my opinion to this question, there is no right or wrong answer
> essentially. In a debate of this matter, there are many variables that can
> and will effect saturation and performance. I would want to consider, off
> the top of my head, Router CPU, Interface MTU, Average packet size (are
they
> all 1500 bytes?), corresponding serialization delay, queue size, etc. Its
> really an open ended question...If you had more specifics, I think you
could
> then determine whether or not your router is actually dropping packets, or
> if you're saturating the pipe.
>
> Mike
>
> Michael Schlenger
> CCIE #7079
> Meridian IT Solutions
> mschlenger@meridianitsolutions.com
> 847.592.3912
>
>
>
> -----Original Message-----
> From: Pratt, Jeremy [mailto:JPratt@coh.org]
> Sent: Wednesday, March 05, 2003 11:25 AM
> To: 'Sam Munzani'; ccielab@groupstudy.com
> Subject: RE: At what percentage of T1 utilization you should see performan
> ce degrade?
>
>
> The 3640 can handle more than 1 full T1. You'll probably have to adjust
the
> queue outbound and inbound queue sizes. I've got a 3640 with 4 T1's on it
> and no one ever has performance problems and all 4 T1's run very hot, 75%
> and up during peak traffic.
>
> -----Original Message-----
> From: Sam Munzani [mailto:sam@munzani.com]
> Sent: Wednesday, March 05, 2003 7:51 AM
> To: ccielab@groupstudy.com
> 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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