Hi Samba, It seems there is firewall between host-X and host-Y, so the cross path packets can not reach the destination? In my understanding, some aspects may impact the result. As far as I know, different vendors maybe provide different implementation. some provide parallel path, like (px) ----- (py) A: host-X host-Y (ax) ----- (ay) while some provide both parallel and cross path, like (px) ------ (py) B: host-X X host-Y (ax) ------ (ay) So, if host-Y takes implementation A, I guess the result would not change even you re-configure the network, because host-Y would not return HBAck in the cross path when it receives the HB message (it doesn't think the cross path is SCTP PATH), I did ever see such device. But, the more important point is host-X, it looks very strange. 1. to mark the destination endpoint IPay as NETWORK DOWN on Host-X when it exceeds max retranmission in same path(cross) consecutively and If the path of IPax -- IPay is OK, this should not happen, this is the key point. Host-X would also send HB to IPpy by the source address IPpx, and send HB to IPay by the source address IPax, and the corresponding HBAck would be returned by host-Y, so num of retransmission would be reset to 0. In the viewpoint of host-X, the right result should be: parallel paths are both OK and cross paths are both invalid, but the association should be OK. Do you see the HB message (or DATA chunk) in the parallel path? or host-X only sends HB in the cross path? By the way, tsvwg@xxxxxxxx is a better list for this discussion. Regards Xiangsong _______________________________________________ Ietf mailing list Ietf@xxxxxxxx https://www.ietf.org/mailman/listinfo/ietf