Router switch fabric protection using forward error correction
First Claim
1. A method comprising:
- launching an aggregation packet from a first module within a switch fabric, wherein the aggregation packet includes a plurality of Internet Protocol (IP) packets and indicates an ingress address assigned to an ingress module and an egress address assigned to an egress module;
receiving said aggregation packet at a second module within the switch fabric;
comparing the ingress address with the address of the first module;
comparing the egress address with the address of the second module;
responsive to the ingress address not being consistent with the address of the first module or the egress address not being consistent with the address of the second module, determining a data path through the switch fabric to be faulty; and
launching a duplicate copy of the aggregation packet from a protection module corresponding to the first module.
7 Assignments
0 Petitions
Accused Products
Abstract
Instead of alternatively utilizing only one fabric or the other fabric of a redundant pair, both fabrics simultaneously transmit duplicate information, such that each packet forwarding module (PFM) receives the output of both fabrics simultaneously. In real time, an internal optics module (IOM) analyzes each information chunk coming out of a working zero switch fabric; simultaneously examines a parallel output of a working one duplicate switch fabric; and compares on a chunk-by-chunk basis the validity of each and every chunk from both switch fabrics. The IOM does this by examining forward error correction (FEC) check symbols encapsulated into each chunk. FEC check symbols allow correcting a predetermined number of bit errors within a chunk. If the chunk cannot be corrected, then the IOM provides indication to all PFMs downstream that the chunk is defective. Under such conditions, the PFMs select a chunk from the non-defective switch fabric. Under error-free normal conditions, however, the PFMs select a chunk arbitrarily from a default switch fabric. In this way, each chunk in real time is selected from a non-defective source and is thus guaranteed to be error free. Accordingly, if a switch fabric fails, no information chunks are lost anywhere in the system.
61 Citations
17 Claims
-
1. A method comprising:
-
launching an aggregation packet from a first module within a switch fabric, wherein the aggregation packet includes a plurality of Internet Protocol (IP) packets and indicates an ingress address assigned to an ingress module and an egress address assigned to an egress module; receiving said aggregation packet at a second module within the switch fabric; comparing the ingress address with the address of the first module; comparing the egress address with the address of the second module; responsive to the ingress address not being consistent with the address of the first module or the egress address not being consistent with the address of the second module, determining a data path through the switch fabric to be faulty; and launching a duplicate copy of the aggregation packet from a protection module corresponding to the first module. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
-
-
10. A system, comprising:
-
a first module comprising hardware and within a switch fabric, the first module configured to launch an aggregation packet, wherein the aggregation packet includes a plurality of IP packets and indicates an ingress address assigned to an ingress module and an egress address assigned to an egress module; a second module within the switch fabric to receive said aggregation packet; a comparison mechanism within the switch fabric and configured to; compare the ingress address with the address of the first module; compare the egress address with the address of the second module; and a fault detection mechanism configured to determine a data path through the switch fabric to be faulty responsive to the ingress address not being consistent with the address of the first module or the egress address not being consistent with the address of the second module; and a protection module corresponding to the first module, the protection module configured to launch a duplicate copy of the aggregation packet. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17)
-
Specification