Messages in this thread |  | | From | Paul Mackerras <> | Date | Tue, 22 May 2001 22:31:14 +1000 (EST) | Subject | Re: SyncPPP IPCP/LCP loop problem and patch |
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rjd@xyzzy.clara.co.uk writes:
> I've hit a problem with the syncPPP module within Linux. > > Under certain conditions (hard to quantify exactly, but try several 8Mbps > streams hitting a relatively slow, say 200MHz processor) the LCP/IPCP > negotiation hits the following loop.
[snip]
> My solution in the patch that follows is to detect the flip-flop using a > counter and then after three occurrences with no genuine IPCP traffic to > modify behavior on receipt of the LCP conf REQ. After three attempts we > acknowledge the LCP conf REQ but stay in the opened state rather than > dropping back and restarting our own LCP negotiation. This is non-RFC1661 > behavior unless you consider it part of the general loop avoidance directive.
Seems to me that when you get the conf-request in opened state, you should send your conf-request before sending the conf-ack to the peer's conf-request. I think this would short-circuit the loop (I could be wrong though, it's getting late).
That behaviour would be in line with the FSM in rfc1661, where the action for event RCR+ in Opened state is "tld,scr,sca/8", i.e. the one action involves sending both the conf-request and the conf-ack. It is debatable to what extent that specifies the order of the messages but it does list the conf-request first FWIW.
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