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:

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.
If no metric is specified for any of the SDPs along the path, the path with the fewest number of SDPs (hops) is selected.
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

Tunnel selection profile applied to...	Resulting tunnel configuration
Spoke SDP binding on a VLL service	This scenario applies to a VLL service with two terminating sites. One of the sites has a spoke SDP binding configured with Auto-Select Transport Tunnel enabled, and a tunnel selection profile with Multi-segment Tunnel Selection enabled. If a valid path is found between the two terminating sites, the spoke SDP bindings and switching sites are created.
VLL service	This scenario applies to a VLL service with two terminating sites. The service is configured with Automatic SDP Binding/PBB Tunnel Creation enabled, and a tunnel selection profile with Multi-segment Tunnel Selection enabled. If a valid path is found between the two terminating sites, the spoke SDP bindings and switching sites are created.
Spoke termination point	This scenario applies to a spoke SDP binding between any two supporting objects. These include (M-)VPLS sites, (M-)VPLS I-sites, (M-)VPLS B-sites, VLL sites, IES L3 access interfaces, VPRN L3 access interfaces, VLL endpoints, and VPLS endpoints. The spoke SDP binding is configured with Auto-Select Transport Tunnel enabled, and a tunnel selection profile with Multi-segment Tunnel Selection enabled. If a termination point is specified, the spoke SDP bindings and return spoke SDP bindings are created. Switching sites are created as follows: If the spoke SDP binding is created on a VLL service, the switching sites are created on the VLL service. If the specified termination point is on a VLL service, the switching sites are created on the VLL service. If neither end of the tunnel is on a VLL service, a new EPIPE service is created. The service component ID is auto-selected by the system. The subscriber ID is the same as the service on which the spoke is created. All other parameters are default values.

Tunnel selection profile applied to...

Resulting tunnel configuration

Spoke SDP binding on a VLL service

This scenario applies to a VLL service with two terminating sites. One of the sites has a spoke SDP binding configured with Auto-Select Transport Tunnel enabled, and a tunnel selection profile with Multi-segment Tunnel Selection enabled. If a valid path is found between the two terminating sites, the spoke SDP bindings and switching sites are created.

VLL service

This scenario applies to a VLL service with two terminating sites. The service is configured with Automatic SDP Binding/PBB Tunnel Creation enabled, and a tunnel selection profile with Multi-segment Tunnel Selection enabled. If a valid path is found between the two terminating sites, the spoke SDP bindings and switching sites are created.

Spoke termination point

This scenario applies to a spoke SDP binding between any two supporting objects. These include (M-)VPLS sites, (M-)VPLS I-sites, (M-)VPLS B-sites, VLL sites, IES L3 access interfaces, VPRN L3 access interfaces, VLL endpoints, and VPLS endpoints.

The spoke SDP binding is configured with Auto-Select Transport Tunnel enabled, and a tunnel selection profile with Multi-segment Tunnel Selection enabled. If a termination point is specified, the spoke SDP bindings and return spoke SDP bindings are created.

Switching sites are created as follows:

If the spoke SDP binding is created on a VLL service, the switching sites are created on the VLL service.
If the specified termination point is on a VLL service, the switching sites are created on the VLL service.
If neither end of the tunnel is on a VLL service, a new EPIPE service is created. The service component ID is auto-selected by the system. The subscriber ID is the same as the service on which the spoke is created. All other parameters are default values.

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

Tunnel selection profile applied to...	Resulting redundant path configuration
Spoke SDP binding on a VLL service	This scenario applies to a VLL service with two terminating sites. One of the sites has a spoke SDP binding configured with Auto-Select Transport Tunnel enabled, and a tunnel selection profile with Multi-segment Tunnel Selection and Redundant Path Selection enabled. If a valid path is found between the two terminating sites, the spoke SDP bindings and switching sites for the redundant path are created. In this case, an endpoint and a return endpoint must be specified.
VLL service	This scenario applies to a VLL service with two terminating sites. The service is configured with Automatic SDP Binding/PBB Tunnel Creation enabled, and a tunnel selection profile with Multi-segment Tunnel Selection and Redundant Path Selection enabled. If a valid path is found between the two terminating sites, the spoke SDP bindings and switching sites for the redundant path are created. From a VLL Service, endpoints on the terminating sites that do not have SAPs or spokes are used for the auto-created spokes. If multiple endpoints exist on a terminating site, the endpoint without any SAPs is used. If multiple viable endpoints are available, an error is raised by the NFM-P and the operation fails. If there are no endpoints available, an endpoint is automatically created with default parameter values, with the following exceptions: The Name parameter value is the endpoint Service ID. The Description parameter value is auto-generated by the system.

Tunnel selection profile applied to...

Resulting redundant path configuration

Spoke SDP binding on a VLL service

This scenario applies to a VLL service with two terminating sites. One of the sites has a spoke SDP binding configured with Auto-Select Transport Tunnel enabled, and a tunnel selection profile with Multi-segment Tunnel Selection and Redundant Path Selection enabled. If a valid path is found between the two terminating sites, the spoke SDP bindings and switching sites for the redundant path are created.

In this case, an endpoint and a return endpoint must be specified.

VLL service

This scenario applies to a VLL service with two terminating sites. The service is configured with Automatic SDP Binding/PBB Tunnel Creation enabled, and a tunnel selection profile with Multi-segment Tunnel Selection and Redundant Path Selection enabled. If a valid path is found between the two terminating sites, the spoke SDP bindings and switching sites for the redundant path are created.

From a VLL Service, endpoints on the terminating sites that do not have SAPs or spokes are used for the auto-created spokes. If multiple endpoints exist on a terminating site, the endpoint without any SAPs is used. If multiple viable endpoints are available, an error is raised by the NFM-P and the operation fails.

If there are no endpoints available, an endpoint is automatically created with default parameter values, with the following exceptions:

The Name parameter value is the endpoint Service ID.
The Description parameter value is auto-generated by the system.

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:

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.
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.