RE: [MLUG - DISCUSSION] Uhhh - topics? I have technical questions !

["Spurling, Shannon " <EMAIL:PROTECTED>]

Well, the lower layer protocols don't really have much to do with the TCP
window size. They only affect it if you have really high latency or they are
dropping packets. the TCP window size is just as likely to be affected by
any link between you and your destination. 3K isn't a bad window size. For
some reason it seams like it's really reasonable to me.

Shannon Spurling
WAN Engineer -Specialist

MOREnet, Network Services, Core Network
3212 Le Mone Industrial Blvd.
Columbia, MO 65201

Main:(573) 884-7200   Fax:(573)884-6673

EMAIL:PROTECTED
EMAIL:PROTECTED

-----Original Message-----
From: Deterding, Brent D (UMC-Student) [mailto:EMAIL:PROTECTED]
Sent: Friday, March 16, 2001 1:22 PM
To: EMAIL:PROTECTED
Subject: RE: [MLUG - DISCUSSION] Uhhh - topics? I have technical
questions !


TCP window size was 3K max (2 1500 byte packets). Both ends would
advertise 32K or whatever but there it stayed at 3K. Very strange.

I assumed it was a limitation of frame relay, but could never get anyone
to tell me as much. thanks!

- Brent 

-----Original Message-----
From: Spurling, Shannon 
To: Deterding, Brent D (UMC-Student)
Sent: 3/16/01 1:17 PM
Subject: RE: [MLUG - DISCUSSION] Uhhh - topics? I have technical
questions !

I think I have an answer for you.... and it's the same one I gave
before. :-)
When you say window size, what are you talking about? The TCP window? IP
packet size? The frame size? In any case, Frame relay uses variably
sized frames, but the provider sets a maximum. The book I am currently
looking at ( which is from a frame relay training class given by ARG)
states that the usual maximum frame size is around 4K. You aren't going
to see that, except at the two FRAD's that are talking across the
physical wire.



Shannon Spurling
WAN Engineer -Specialist

MOREnet, Network Services, Core Network
3212 Le Mone Industrial Blvd.
Columbia, MO 65201

Main:(573) 884-7200   Fax:(573)884-6673

EMAIL:PROTECTED
EMAIL:PROTECTED

-----Original Message-----
From: Deterding, Brent D (UMC-Student) 
Sent: Friday, March 16, 2001 1:04 PM
To: Spurling, Shannon ; EMAIL:PROTECTED ' '
Subject: RE: [MLUG - DISCUSSION] Uhhh - topics? I have technical
questions !


Doh! Not MTU. Window size was max 3K and I could never figure out why.
Both ends would advertise 16K or 32K but it stuck there at 3K ? I beter
know that MTU on ethernet is 1500 or I'm in trouble. Just mis-spoke.

Can someone explain to me why the hell my old DSL line from MU had an
MTU of no larger than 3K ?
>The DSL goes into the frame switch downtown. Frames are only limited
>by the MTU. If the MTU is too large, you get really big frames. Imagine
>running a train switching yard. If all your trains had a large number
>of cars, you have to wait till they all go on the track before you
could
>switch in the next train. There is also no reason to have frames larger
>than 1500. Ethernet's MTU is defined as 1500. If you have packets
larger
>than that, they will have to be fragmented when they get to the
ehternet.
>And nothing will stuff packets together to try and fit the MTU. It's
one
>packet at a time, unless it has to be broken.

--
To manage your subscription, go to http://mlug.missouri.edu/members/edit.php

Archives are available at http://mlug.missouri.edu/list-archives/
--
To manage your subscription, go to http://mlug.missouri.edu/members/edit.php

Archives are available at http://mlug.missouri.edu/list-archives/