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US 7,120,151 B1Granted
Method for fast label switchover with multiprotocol label switching
AssigneeCisco Technology, Inc.
InventorsHariprasada R. Ginjpalli, Durai Chinnaiah, Jayakumar Jayakumar
Life of this patent
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Abstract
Two or more virtual circuit (VC) labels associated with a tunnel label are mapped to a group identification (GID). The tunnel label is mapped to the GID in a GID table. When the two or more VC labels are to be associated with a new tunnel label, the tunnel label in the GID table is changed to the new tunnel label.
Claims28
A method of switching a Label Switch Path (LSP) in a multiprotocol label switching (MPLS) network by a Label Switch Router (LSR), the method comprising:
- mapping one or more virtual circuit (VC) labels associated with a first tunnel label to a first group identification (GID);
- mapping the first GID with the first tunnel label;
- remapping the first GID with a second tunnel label when a failure occurs that necessitates changing the first tunnel label;
- forwarding a datagram having a VC label associated with the first tunnel label using the second tunnel label instead of the first tunnel label;
- and
- mapping one or more VC labels associated with a third tunnel label to a second GID, the second GID being different from the first GID.
3 more elements
A method of maintaining tunnel labels by a Label Switch Router (LSR), the method comprising:
- forming a label table that maps virtual circuit (VC) labels to group identifications (GIDs), each of the VC labels that was previously mapped to a same tunnel label being mapped to a same group identification;
- forming a GID table that maps each of the different GIDs to a different tunnel label that identifies an adjacent LSR;
- forwarding a datagram using a VC label associated with the datagram to determine a GID for the datagram from the VC labels in the label table and using the determined GID to determine a tunnel label for the datagram from the tunnel labels in the GID table;
- and
- associating the VC labels in a group of VC labels having the same GID with a new common tunnel label by rewriting one entry in the GID table with the new common tunnel label to update the GID table and reflect the new common-tunnel label when a failure occurs that necessitates changing the first tunnel label.
2 more elements
A computer readable medium having stored thereon sequences of instructions which are executable by a system, and which, when executed by the system, cause the system to:
- form a label table that maps virtual circuit (VC) labels to group identifications (GIDs), each of the VC labels that was previously mapped to a same tunnel label being mapped to a same group identification;
- form a GID table that maps each of the different GIDs to a different tunnel label that identifies an adjacent LSR;
- forward a datagram using a VC label associated with the datagram to determine a GID for the datagram from the VC labels in the label table and using the determined GID to determine a tunnel label for the datagram from the tunnel labels in the GID table;
- and
- associate the VC labels in a group of VC labels having the same GID with a new common tunnel label by rewriting one entry in the GID table with the new common tunnel label to update the GID table and reflect the new common-tunnel label when a failure occurs that necessitates changing the first tunnel label.
2 more elements
An apparatus, comprising:
- a bus;
- a memory coupled to the bus;
- a processor coupled to the memory and the bus, the processor configured to
- form a label table that maps virtual circuit (VC) labels to group identifications (GIDs), each of the VC labels that was previously mapped to a same tunnel label being mapped to a same group identification,
- form a GID table that maps each of the different GIDs to a different tunnel label that identifies an adjacent LSR,
- forward a datagram in a multiprotocol label switching (MPLS) network using a VC label associated with the datagram to determine a GID for the datagram from the label table and using the determined GID to determine a tunnel label for the datagram from the tunnel labels in the GID table, and
- associate the VC labels in a group of VC labels having the same GID with a new common tunnel label by rewriting one entry in the GID table with the new common tunnel label to update the GID table and reflect the new common-tunnel label when a failure occurs that necessitates changing the first tunnel label.
4 more elements
An apparatus, comprising:
- means for forming a label table that maps virtual circuit (VC) labels to group identifications (GIDs), each of the VC labels that was previously mapped to a same tunnel label being mapped to a same group identification;
- means for forming a GID table that maps each of the different GIDs to a different tunnel label that identifies an adjacent LSR;
- means for forwarding a datagram in a multiprotocol label switching (MPLS) network using a VC label associated with the datagram to determine a GID for the datagram from the label table and using the determined GID to determine a tunnel label for the datagram from the tunnel labels in the GID table;
- and
- means for using a backup tunnel label in the GID table to forward the datagrams to a next router instead of a current tunnel label when the datagrams cannot be forwarded to the next router using the current tunnel label, the backup tunnel label on the label stack above the current tunnel label and corresponding to the GID associated with the current tunnel label when a failure occurs that necessitates changing the first tunnel label.
2 more elements
A Label Switch Router (LSR), comprising:
- a bus;
- a memory coupled to the bus;
- a processor coupled to the memory and the bus, the processor to map one or more VC labels associated with a first tunnel label to a first group identification (GID),
- map the first GID with the first tunnel label,
- remap the first GID with a second tunnel label when a failure occurs that necessitates changing the first tunnel label,
- forward a datagram having a VC label associated with the first tunnel label using the second tunnel label instead of the first tunnel label, and
- map one or more VC labels associated with a third tunnel label to a second GID, the second GID being different from the first GID.
4 more elements
A computer readable medium having stored thereon sequences of instructions which are executable by a system, and which, when executed by the system, cause the system to:
- map one or more virtual circuit (VC) labels associated with a first tunnel label to a first group identification (GID) in a Label Switch Router (LSR);
- map the first GID with the first tunnel label;
- remap the first GID with a second tunnel label when a failure occurs that necessitates changing the first tunnel label,
- forward a datagram having a VC label associated with the first tunnel label using the second tunnel label instead of the first tunnel label;
- and
- map one or more VC labels associated with a third tunnel label to a second GID, the second GID being different from the first GID.
3 more elements
Dependencies are inferred from the claim text.