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802.17c Protected Inter-Ring Connection. Rafi Ram - Corrigent Systems May 2007. PIRC Sublayer in MAC Block Diagram. PIRC Suggestion Highlights. Stations A & B are members of a protection group (PG) for interconnect between two rings
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802.17cProtected Inter-Ring Connection Rafi Ram - Corrigent Systems May 2007
PIRC Suggestion Highlights • Stations A & B are members of a protection group (PG) for interconnect between two rings • Station A and station B are protection group members (PGM) • One of the stations in a PG is provisioned as the “0” member, and the other as the “1” member • One of the interconnected rings shall be provisioned as the “primary” ring and the other as “secondary” ring
Network Diagram • Stations A & C are “peer” stations • Stations B & D are “peer” stations • Stations A & B are “mate” stations • Stations C & D are “mate” stations • Stations A & B are protection group members on the primary ring • Station A is the “0” member and station B is the “1” member • Stations C & D are protection group members on the secondary ring • Station C is the “0” member and station D is the “1” member
PGM State Machine • Self-OK : The communication with the peer station is OK (and no “admin-down”) • Mate-OK : The protection group stations are visible in the topology of both the primary and secondary rings, and the mate station advertises status “self-OK” • The 802.17c specification should not include a mandatory method for determining the value of the “hold-off” timer
myFlow(frame) Function • The function could be used to implementation of the load-balancing functionality • On of the possible implementations of the myFlow function could be : myFlow(frame) = (hashing(frame) modulo 2) == member-type • “member-type” equals to 0 if the station is the 0 member, and equals to 1 if the station is the 1 member
PIRC Sublayer Logic on the Path Client MAC as Pseudo-Code if (MAC is on primary ring) forward frame else if (((PG state is “fwd-mine”) and myFlow(frame)) or (PG state is “fwd-all”)) then forward frame else discard frame
PIRC Sublayer Logic on the Path MAC Client as Pseudo-Code if (MAC is on primary ring) if ((PG state is “fwd-all”) and (RPR SA is the mate MAC address)) discard frame else forward frame else if (RPR SA is the mate MAC address) discard frame else if (((PG state is “fwd-mine”) and myFlow(frame)) or (PG state is “fwd-all”)) then forward frame else discard frame