[tcpm] 793bis: removing "Window Management Suggestions"

[Wesley Eddy <[e-mail]>]

In the latest revision of the 793bis draft, I added content from RFC 
1122 on the SWS avoidance algorithms for sender-side and receiver-side.  
These are laid out in 1122, but were not present in 793.

793 includes a section called "Window Management Suggestions", that I 
believe was a precursor to the more-developed content in 1122 on:

(1) SWS avoidance sender-side algorithm

(2) SWS avoidance receiver-side algorithm

(3) Nagle algorithm

(4) delayed ACKs

(5) zero-window probing


With all of that 1122 content worked into 793bis, I did not think it 
made sense to retain this section of the document, but it will be good 
to confirm that with the WG.

For convenience, the content from 793 that I believe is no longer needed 
is pasted below:

     Window Management Suggestions

       Allocating a very small window causes data to be transmitted in
       many small segments when better performance is achieved using
       fewer large segments.

       One suggestion for avoiding small windows is for the receiver to
       defer updating a window until the additional allocation is at
       least X percent of the maximum allocation possible for the
       connection (where X might be 20 to 40).

       Another suggestion is for the sender to avoid sending small
       segments by waiting until the window is large enough before
       sending data.  If the the user signals a push function then the
       data must be sent even if it is a small segment.

       Note that the acknowledgments should not be delayed or unnecessary
       retransmissions will result.  One strategy would be to send an
       acknowledgment when a small segment arrives (with out updating the
       window information), and then to send another acknowledgment with
       new window information when the window is larger.

       The segment sent to probe a zero window may also begin a break up
       of transmitted data into smaller and smaller segments.  If a
       segment containing a single data octet sent to probe a zero window
       is accepted, it consumes one octet of the window now available.
       If the sending TCP simply sends as much as it can whenever the
       window is non zero, the transmitted data will be broken into
       alternating big and small segments.  As time goes on, occasional
       pauses in the receiver making window allocation available will
       result in breaking the big segments into a small and not quite so
       big pair. And after a while the data transmission will be in
       mostly small segments.

       The suggestion here is that the TCP implementations need to
       actively attempt to combine small window allocations into larger
       windows, since the mechanisms for managing the window tend to lead
       to many small windows in the simplest minded implementations.


Any thoughts or feedback on removing this from 793bis will be 
appreciated, thanks!