Apparatus and method for internet protocol flow ring protection switching

An Internet protocol communications a stem comprising:

• an ingress router;
• an egress router, and
• a plurality of explicitly routed label switched paths contemporaneously carrying like datagrams, and established for single flow between the ingress router and the egress router, wherein the ingress router, the egress router, and any intermediate routers comprise:
• a first port through which datagrams for a given flow may be received from a primary path that originates at the ingress router;
• a second port through which datagrams for the flow may be received from at least one secondary path contemporaneously with the reception at said first port, said at least one secondary path at least partially distinct from the primary path but originating at the same ingress router;
• and
• a controller for preferentially selecting datagrams received via said first port, said controller comprising a memory for program instructions, and a processor for executing said instructions to configure the router to perform the steps of:
• establishing the primary path for the given flow between the ingress router and the egress router;
• establishing said at least one seconds path for a given flow between the ingress muter and the egress router;
• in response to a failure in the primary path, automatically selecting an operational one of said at least one secondary paths for primary communication between the ingress router and the egress router;
• and
• in response to the selection of said as secondary path, automatically establishing at least one replacement secondary, at least partially distinct, path.

A method of communicating datagrams through an Internet protocol network comprising the steps of:

• for each router, establishing a primary explicitly routed label switched path for a given data flow between an ingress router and an egress router;
• for each router, establishing at least one secondary, at least partially distinct, explicitly routed label switched path for a given data flow between the ingress router and the egress router, such that the data flow from said at least one secondary, at least partially distinct, explicitly routed label switched path is received by a second port of the egress router contemporaneously with the reception of the data flow from said primary explicitly routed label switched path at a first port of the egress router;
• in response to a failure in the primary explicitly rout label switched path of any one or more of said routers, automatically selecting an operational one of said at least one secondary explicitly routed label switched paths, for each of the tailed routers, for primary communication between the ingress router and the egress router;
• and
• in response to the selection of said secondary explicitly routed label switched paths, automatically establishing at least one replacement secondary, at least partially distinct, explicitly routed label switched path.