From: Howard C. Berkowitz (hcb@xxxxxxxxxxxx)
Date: Thu Jun 13 2002 - 12:09:35 GMT-3
At 9:36 AM -0400 6/13/02, Thomas Larus wrote:
>Some practice scenarios' solutions use byte counts that seem too convenient
>to be realistic. I read somewhere that dlsw+ tends to be 512, I think. I
>have read that telnet packets are extremely small, 64? I think. Are they
>all multiples of 64?
Telnet packets from the client to the host, under default
assumptions, are often 41 bytes: 20 bytes of IP, 20 bytes of TCP,
and one Telnet character. Many hosts will round 41 up to the nearest
even buffer size, which can be between 42 and 48, and sometimes 64.
Using Van Jacobson header compression will reduce this Telnet packet
size to 6 bytes. The cost of this is much higher processing load on
the routers.
From the server to the client, telnet packets may be much longer, but
typically 40 bytes of uncompressed header plus the average line
length, up to 72-80 bytes.
There is another odd short packet length that you will see in the
Internet: 40 bytes, again possibly rounded up. This is a IP/TCP
acknowledgement for an HTTP packet.
File transfer protocols generally try to use the maximum MTU.
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