On Mon, Apr 23, 2007 at 04:03:56PM +0300, Alper Yegin wrote: > > There is one problem with allowing ping in access phase only. > > > > Suppose both a PaC and a PAA are in access phase, and the PaC sends a > > ping request while the PAA sends a PAR to start re-authentication at > > the same time. Then PAA will not accept the ping request because it > > has entered re-authentication phase. If ping is allowed in any > > state, then PAA can answer to the ping request. > > I think the issue is about having two outstanding requests (one PANA-Ping > and one other) at the same time. The PAA (or PaC) having to respond to a > PANA-Ping-Request while it has an outstanding request shall not have a > problem. What do you think?
I think having two outstanding requests sent in different directions is acceptable. > > > > BTW, I've found another issue here. In the above example, The PaC > > will accept the PAR sent from the PAA and can return a PAN, but it > > cannot send a new PAR (this can happen if the PAN does not carry EAP), > > until the ping request is answered. This is actually breaking > > lock-step behavior of PANA (queuing requests should not be required > > for a lock-step protocol). > > What would be the issue of having request queuing? Queueing itself may not be an issue. But the actual issues is the sender would need to distinguish two cases (i.e., if there is an outstanding ping request or not) for each state. For example, supposed that the PaC is in a state waiting for a ping answer. If another event that needs to send a PAR is generated, then the PaC processes the event, generates and queues a PAR and transits to a state that is waiting for a PAN, and it is still waiting for a ping answer. This would require N*2 states (N is number of states except for ping, multiplied by 2 to consider whether there is a ping request or not. > > > I'd like to see if we can avoid creating special case for PANA-Ping messages > (e.g., putting them under a separate treatment). I think the only way to avoid it is: - Allow sending ping request in access phase only. - Allow receiving ping request in any phase. - When there is an outstanding ping request, discard all incoming messages except for ping answer or error request sent in resopnse to the ping request. This may be an acceptable operation. Yoshihiro Ohba > > Alper > > > _______________________________________________ Pana mailing list [email protected] https://www1.ietf.org/mailman/listinfo/pana
