Browse Prior Art Database

Improvement of Flow Control (RFC0210) Disclosure Number: IPCOM000002653D
Original Publication Date: 1971-Aug-01
Included in the Prior Art Database: 2019-Feb-13
Document File: 2 page(s) / 3K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

W. Conrad: AUTHOR

Related Documents

10.17487/RFC0210: DOI

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 56% of the total text.

Request for Comments # 210 W. Conrad Categories C.4 Harvard NIC 7189 16 August 71

Improvement of Flow Control

The current "give back" - "return" scheme seems to put the cart before the horse in that the "return" command indicates the amount of space the sending host is returning rather than the amount of space it has left after decrementing by the amount specified in the "give back" command. Considering the fact that allocation counters at sending and receiving hosts may get out of synchronization and the fact that the receiving host has a preemptive priority in the allocation of its resources, it is only logical that the receiving host be able to find out exactly how much of its buffer space a sending host thinks it can claim.

If the "return" command is to accurately reflect a sending host’s current allocation, and if successive "give backs" are to produce "return" commands which can be properly interpreted, certain race conditions must be avoided. A "give back" must be answered by a "return" and no more "give backs" can be issued until that "return" is received. In some sense, a "return" command as here proposed is really a give back reply, and, perhaps, should implemented under that name. On the sending side, the "return" command must not be issued as long as a data RFNM is awaited on the link to which the "return" refers. As soon as the net is clear of data messages, the "return" may be sent and data transmission may continue when the RFNM for this message containing the "return" command is received.

The current "give back" command uses fractions and has a format different from the "allocate" and "return" commands making processing unnecessarily c...