Multi-segment tunnel selection
Overview
Multi-segment tunnel selection functionality enhances tunnel selection functionality to allow the system to select intermediate NEs in a path, as well as the service tunnels from a selected intermediate NE to its next hop. Multi-segment tunnel selection functionality is used to select existing SDPs. It cannot create new SDPs.
Tunnels are selected based on the following criteria:
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If a metric value is specified for any of the SDPs along the path, the path with the lowest sum of the metric property for all SDPs along the path is selected.
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If no metric is specified for any of the SDPs along the path, the path with the fewest number of SDPs (hops) is selected.
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If two paths or SDPs are equal based on the selection criteria mentioned above, the SDP/path with the lowest load factor (number of services using that SDP) is selected.
Multi-segment tunnel selection functionality must be enabled on the Services tab on the NFM-P System Preferences form, as well as at the tunnel selection profile level. The table below describes the objects to which a tunnel selection profile with multi-segment tunnel selection can be assigned, and the service tunnel configurations that result.
Table 70-1: Multi-segment tunnel selection scenarios
Redundant path selection
If Redundant Path Selection is enabled on a tunnel selection profile, a redundant path is created. Redundant Path Selection can only be enabled if Multi-Segment Tunnel Selection is also enabled. The selected redundant path does not use any of the same switching sites as the primary path. Redundant path selection is not supported when a termination point is selected on a spoke SDP binding. The table below describes the objects to which a tunnel selection profile with redundant path selection can be assigned, and the service tunnel configurations that result.
Table 70-2: Redundant path selection scenarios
Service tunnel required bandwidth
Service tunnel bandwidth requirement can be specified as an additional constraint in the path search process. When required bandwidth is specified at the service or service site level, the selection of service tunnels is based on bandwidth availability. If all other tunnel selection criteria are equal, the tunnel with higher available bandwidth is selected.
Note: Service tunnel required bandwidth functionality requires that the CPAM feature set is correctly configured. See the NSP NFM-P Control Plane Assurance Manager User Guide for information about the CPAM feature set. Additionally, the Multi-Segment Tunnel Selection and Service Bandwidth Management system options must be enabled.
All physical links between service sites must be configured (either manually or through LLDP) before bandwidth can be allocated to service tunnels.
This functionality applies to RSVP tunnels on VLL, VPLS, and MVPLS services, and G.8032 Ethernet rings on VPLS services. Bandwidth requirement criteria are specified at the service level, and are inherited by all associated service sites by default. Optionally, bandwidth requirement criteria can be specified on individual service sites. Bandwidth requirements are specified on the service or site configuration form, Bandwidth tab - Required Bandwidth sub-tab.
Bandwidth can be user-specified on a per-CoS basis, or it can be calculated automatically. When bandwidth values are calculated automatically, the calculation is based on the ingress CIR configurations, taking the sum of the bandwidths for the endpoints (SAPs) connected to each site. In the event that two sites with different bandwidth sums are connected by a service path, the lower of the two bandwidth sums is booked for the service path.
There are two options that determine how service bandwidth is booked in the network:
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For Epipe services only, the user has the option to enable bandwidth booking on both the active and redundant service paths (if a redundant path is available). Otherwise, only the active path is booked.
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For all VLL, VPLS, and MVPLS services, the user has the option to enable bandwidth booking on all operationally up LSP paths in use by the service. Otherwise, only the active path is booked.