10 GMPLS

Generalized Multiprotocol Label Switching (GMPLS) is an extension of the MPLS signaling protocols to enable easy setup/restoration for use in SDH, OTN, and WSON. It is a technology independent protocol, applicable to SDH, OTN, and WSON thus promising the possibility of a unified control plane for end-to-end provisioning across different layers of the network. Every node in a GMPLS cloud has a network view of the topology and failures, and hence capable of autonomously re-configuring/routing the circuits in response to network faults in a deterministic way. The GMPLS implements an additional level of protection to the networks by establishing one or more pre-signaled backup paths (reroute) for each connection and enabling very fast switching in case of failure.

You can select the desired service type from the following list:

• Bronze service: select Service_1

• Silver service: select Service_1_R

• Gold service: select Service_1_1_R

• Platinum service: select Service_1_1_F

The two services can be paired together if service pairing is set as Enabled.

Similarly, you can follow reroute option if reroute option is set as Enable. This is applicable only to the provisioned circuit. The Reroute FreqTuning parameter checks for availability of other frequencies to reach the egress path in case of fiber cut.

Route selection metric

You can select the route selection metric type from the drop down list to be followed by GMPLS circuits across network.

• Available_Bandwidth: Indicates rerouting is based on the available path with maximum bandwidth.

• Number of Hops: Indicates rerouting path selection is based on shortest path with least number of hops/nodes.

• User_Defined: Indicates rerouting path selection is based on cost defined by the user for each path in a GMPLS network.

• Latency: Indicates rerouting path selection is based on the latency/delay.

10.1 Bronze service (Service_1)

It is an unprotected service. Bronze service have dedicated work path only. In case of failure in traffic flow path, the traffic goes down. The cross-connects is retained and once the fault is rectified, the traffic is restored.

10.2 Silver service (Service_1_R)

It provides 1+R protection and a GMPLS based restoration. Silver service has two types of reversion mode:

• Revertive

• Non-revertive

10.2.1 Revertive

A dedicated work path exists for silver service (revertive). When a work path fails, a protect path is found, and traffic is redirected there. The cross-connects will always be present in the job path. After the failure in the work path, a new way is discovered. When it is restored, traffic returns to the work path. When traffic returns to the work path, the reroute path is removed.

10.2.2 Non-revertive

A dedicated work path exists for silver service (revertive). When a work path fails, a protect path is found, and traffic is redirected there. The cross-connects will always be present in the job path. After the failure in the work path, a new way is discovered. When it is restored, traffic returns to the work path. When traffic returns to the work path, the reroute path is removed.

10.3 Gold service (Service_1_1_R)

Gold service offers GMPLS-based restoration and 1+1 protection. The focused work and protective path of the gold service. The traffic shifts to protect the path in the event of a failure in the work path. The cross-connects is kept constantly in the work path. If the original work path is not restored after any failure in the protect path, the traffic either switches to the original work path or reroutes to a new re-route path (if the work path is restored).

10.4 Platinum service (Service_1_1_F)

Platinum service offers continuous 1+1 protection. The focused work and protective path of platinum service. Traffic switches to the protect path in the event of a work path failure, and a new work path called the redirected work path is generated. A new protect path with the name redirected protect path is generated in the event that the protect path fails. One extra work/protect path is produced for each time the work/protect path fails.

NOTE 1: Single or more than one direction less (local drop) ROADMs are supported.

The Bronze/Silver (Non-revertive) service creation supported from MDU which is directly connected at directional ROADM.

NOTE 2: For WSON, the protection switching and rerouting times are in the order of few seconds.