RE: MPA issue (3): Rejected Connection bit
"Talpey, Thomas" <[email protected]>
| Newsgroups | gmane.ietf.rddp |
|---|---|
| Message-ID | <[email protected]> |
In my view, the state of the connection after an MPA reject is up the responding ULP (i.e. the one that rejected). The connection, initially, remains in TCP streaming mode. The ULP consumer may opt to close the connection, return the connection to MPA responder mode (before consuming any TCP stream data), or simply remain in TCP. The decision is not MPA's, nor should it be. Tom. At 07:32 PM 4/6/2004, Carrier, John wrote: >I guess I would like to hear a clarification for how the rejected bit would >be used. > >In the startup scenarios described in the MPA draft, when the MPA Responder >sends the MPA Reply Frame, the responder 'binds' DDP to MPA so that, after >sending the reply frame, the MPA Responder will be ready to receive FPDUs >and pass them to DDP. If the Request Frame is invalid or if the private >data is unacceptable, then the ULP should close the connection without >sending a Reply Frame. > >Adding the rejected bit enables the ULP to send a Reply Frame without >binding DDP to MPA. The Reply Frame may also contain private data that >further describes why the request was rejected. > >If that is the intent, then what should the state of MPA be after sending >the Reply Frame with the rejected bit set? Does it return to 'responder >mode' so that the Initiator can resend the MPA Request Frame or does it >transition to a new state where it drops any received data while it waits >for the ULP to close the connection? > >If this has already been discussed on the list, please point me to the thread. > >thanks. > >--jc > > >John Carrier >Adaptec > >> -----Original Message----- >> From: [email protected] [mailto:[email protected]]On Behalf Of >> [email protected] >> Sent: Monday, March 29, 2004 5:21 PM >> To: [email protected] >> Subject: [rddp] MPA issue (3): Rejected Connection bit >> >> >> Moving on to issue (3), the Seoul minutes say: >> >> (3) Rejected Connection bit. Dissension expressed, this leads to >> interoperability issues because it forces a ULP to >> interpret private >> data to figure out that the connection setup failed, and requires >> MPA to handle TCP close specially (more detail in mail to list). >> Further discussion: >> >> Q: If MPA does not do "teardown", why is the bit needed to >> free resources at MPA layer? >> A: Practically speaking, implementations will allocate and free >> resources in MPA (e.g. connection model in kernel), this enables >> layering and better control. >> A: The bit will prevent some timed-wait resource consumption issues, >> if used properly (this is about cooperating systems, not malicious >> resource consumption attacks). >> >> Rough consensus in room to include the bit. Take to list. >> >> I suggest to the WG that the right thing to do is include this bit >> because it produces better behavior in an important error case for >> cooperative clients where something is misconfigured. This bit >> allows the RDDP layers to immediately know that a connection setup >> has failed and release/reuse any resources committed to it without >> waiting for a ULP to look at the private data that came back. It >> also ties the fact that the connection is closing with the >> associated private data unambiguously (both can be immediately >> logged at RDDP level). Yes, this is optimizing an error case, >> but it seems to be common enough/of sufficient concern to be >> worth spending a bit on. That was where the discussion among >> the subset of us who were in Seoul wound up. >> >> Comments? I intend to let the technical discussion run on this >> before trying to call consensus on the list. >> >> Thanks, >> --David >> >> ---------------------------------------------------- >> David L. Black, Senior Technologist >> EMC Corporation, 176 South St., Hopkinton, MA 01748 >> +1 (508) 293-7953 FAX: +1 (508) 293-7786 >> [email protected] Mobile: +1 (978) 394-7754 >> ---------------------------------------------------- >> >> >> _______________________________________________ >> rddp mailing list >> [email protected] >> https://www1.ietf.org/mailman/listinfo/rddp >> > >_______________________________________________ >rddp mailing list >[email protected] >https://www1.ietf.org/mailman/listinfo/rddp