Service tunnel overview

Overview

A service tunnel is an entity used to uni-directionally direct traffic from one device to another device. The service tunnel is provisioned to use a specific encapsulation method, such as GRE or MPLS, and the services are then mapped to the service tunnel. For instance, multi-NE VLL and VPLS traffic is transmitted using uni-directional service tunnels in this way.

The most common type of tunnel used in NFM-P is a Service Distribution Point binding. Service tunnels originate on an SDP on a source NE and terminate at a destination NE. The destination NE directs packets from the service tunnel to the correct service egress interfaces (SAPs) on that device. Services that originate and terminate on the same NE do not require service tunnels, because the same NE is both the source and the destination.

However, because the concept of a tunnel is a logical construct within the NFM-P, a number of different configurable objects can actually be used as service tunnels, including:

• SDP binding:

  Because SDP bindings can be associated to a service of any type, the service tunnel discovery includes services that are associated to SDP bindings of a given service.

• Service to Tunnel Association:

  Discovery adds tunnels that are associated to a given service.

• G.8031 Ethernet tunnel:

  Discovery adds the global Ethernet Tunnel that the Tunnel Endpoint (SAP’s terminating port) is a member of.

• G.8032 Ethernet ring:

  Discovery adds the Ethernet Ring that the Ethernet Element is a member of.

• G.8032 Ethernet radio ring:

  Discovery adds the Ethernet radio ring that the Ethernet Element is a member of. See the NSP NFM-P Microwave Radio User Guide for more information.

• PBB:

  Discovery adds the VPLS or MVPLS services which contain the PBB tunnel (B-Sites) of the given Epipe or VPLS.

• P2MP RSVP LSP:

  Discovery adds the P2MP LSPs retrieved from the MVPN LSP Template associated to PIM sites.

• Optical Transport Service:

  Discovery adds optical services that are traversing network interfaces which are being used by an L2/L3 VPN through any static, dynamic or SR-TE LSPs that are bound to SDPs on the service if the following are true:

  • LSPs are bound to service tunnels (SDPs) on the service

  • One or more of the corresponding hops on the LSP active path share the same port with the optical service termination

• Mobile backhaul (applicable to Wavence SM and 7705 SAR on MPLS-based services running over VLAN):

  Discovery adds Wavence VLL services that are associated to an SDP tunnel or are traversing through network interfaces which are being used by an L2/L3 VPN through any static, dynamic or SR-TE LSPs that are bound to SDPs on the service.

The Service Tunnels tab exists on the applicable service configuration forms. This tab lists the objects considered as service tunnels (such as SDPs, Ethernet rings, Ethernet tunnels, other services) that are currently used by the service you are querying. The associated Discover Service Tunnels button removes any previously discovered service tunnels on the service and initiates a manual rediscovery of the tunnels, based on direct usage and current service configurations.

For composite services, the service tunnel discovery action initiates the discovery of service tunnels on the participating services. The listing includes the service tunnels that are currently used by member services.

The Flow-through Services tab is on the configuration forms of the objects that can be used as a service tunnel. The tab lists the other services that are currently using the object you are querying as a service tunnel. The associated Discover Flow-through Services button removes any previously discovered flow-through services and initiates a manual rediscovery of the tunnels, based on direct usage and current service configurations.

For composite services, the concept of using a service as a service tunnel is not supported. The Flow-through Services tab does not appear on the composite service configuration forms.

For alarm management, an association type of alarm relationship exists between a service and the service tunnels that the service uses. This allows the service tunnel alarms to propagate up to the service level. These association alarms are displayed on the Alarms on Related Objects tab, under the Faults tab of the service. Because this is a one-way association, service alarms are not propagated to the service tunnels that the service is using.