>>>>> "Martin" == Martin Stiemerling <mls.i...@gmail.com> writes:
Martin> Sam, Martin> On 08/24/2013 03:41 PM, Sam Hartman wrote: >>>>>>> "Martin" == Martin Stiemerling >>>>>>> <martin.stiemerl...@neclab.eu> writes: >> Martin> Hi Sam, Martin> On 08/14/2013 10:16 PM, Sam Hartman wrote: >> >>>>>>> "Joseph" == Joseph Salowey (jsalowey) >> <jsalo...@cisco.com> >>>>>>> writes: >> >> Joseph> [Joe] Retransmission and timeout behavior for EAP is Joseph> discussed in the EAP RFC 3748 Section 4.3. >> >> >> >> Echoing Joe's point, we over in abfab >> (draft-ietf-abfab-gss-eap) >> would be really unhappy if EAP >> method specs started discussing >> timeouts. >> Martin> It is not about the EAP timeouts for whole messages, but Martin> timeouts for fragments are not defined in RFC 3748 and must Martin> be defined somewhere, as well as, what happens if timeouts Martin> are exceeded for fragments. >> >> If an inner method supports fragmentation, then each fragment is >> a "whole EAP message," in your terminology quoting RFC 3748. Martin> So, for the unexperienced EAP people like me, TEAP is the Martin> inner method? TEAP is running within EAP. *sigh* I'm sorry, I used the wrong terminology. Inner method doesn't come up here; that would be a case where say you were running EAP-AKA inside TEAP. Rephrasing to apply to your situation. If an EAP method supports fragmentation, that fragmentation is handled by the method. That is both fragmented and un-fragmented messages within the view of the method are "whole messages," as considered by EAP. We see a similar situation with IP and ethernet. Ethernet (at least the version I learned about back when ethernet was simple) doesn't support fragmentation. Each IP datagram, whether it's a fragment or not, is a whole ethernet frame. As it happens, ethernet doesn't provide end-to-end service, and for a bunch of other reasons tdhat don't apply to EAP, you need to talk about retransmission at the IP layer as well as to some extent at the ethernet layer. However, with EAP, the EAP layer provides a reliable end-to-end service and entirely takes on the retransmission task (unless EAP itself is running over a lower layer that takes on retransmission and sets the EAP retransmit timeout to infinite). A method can fragment, but unlike IP, the fragmentation mechanism is entirely disjoint from retransmission. There are probably inefficiencies here because of that disconnect. however, EAP is not trying to be an efficient transport. And handling retransmission on the EAP side of the boundary and fragmentation on the method side side of the abstraction boundary provides valuable benefits for EAP. Like the state machine between the method and EAP can be lock-step without the method ever triggering an event. That's quite important for the way people have grown to build EAP software. _______________________________________________ Emu mailing list Emu@ietf.org https://www.ietf.org/mailman/listinfo/emu