Re: TCP header

From: Eric Travis ([email protected])
Date: Thu Nov 13 1997 - 23:03:42 EST


> 1. The "window scale option" is a three byte TCP option, that takes
> place only during the TCP connection (during SYN), is that right?

Correct - so once you've told your peer your scale factor that's it
for the life of the connection.

Large windows (> 2^16 - 1 octets) require use of window-scaling, but
use of window-scaling does not imply large-windows; You can scale even
"small" windows if you desire.

> 2. The timestamp option (RFC1323) we have been discussing for a while
> now, how many TCP option header bytes is it? Are the PAWS header bytes
> (if any) included in this number?

10 bytes:
 ====================================================
 | kind = 8 | length = 10 | timestamp | echo reply |
 | 1 byte | 1 byte | 4 bytes | 4 bytes |
 ====================================================

There are no PAWS specific bits (aside from the timestamp itself).

> 3. Does anybody knows for sure whether the timestamp option
> (for RTTM and PAWS) is implemented in the Alpha DU4.0 TCP Reno?

Dunno - but if they support RFC-1323, then they've got the timestamp
option. I believe (this might be incorrect) DU4.0 has 1323 support,
but it is disabled by the default configuration.

Regards,

Eric



This archive was generated by hypermail 2b29 : Mon Feb 14 2000 - 16:14:33 EST