The following guidelines apply for BFD over LAG links:
The local address used for BFD sessions over LAG links cannot be an IP interface address that is associated with R-VPLS services.
When a micro-BFD session is established, resources are allocated per member port of the LAG. These resources are taken from the pool that is used to map packets to SAPs. Therefore, adding ports to the LAG on which the micro-BFD session is configured reduces the number of SAPs.
When configuring a micro-BFD session with dot1q encapsulation, an IP interface with dot1q explicit null SAP (:0 SAP) must be configured on the port for the BFD session to be operational. The local IP address of the BFD session can inherit the IP address of the IP interface that is configured with dot1q explicit null SAP or any other IP interface with the LAG.
The local IP interface address used for micro-BFD sessions must match the address of an IP interface configured on the LAG. If an IP interface is configured with an encapsulation of dot1q explicit null SAP configured on the LAG (lag:0), the uBFD session is not established unless one of the following occurs:
The interface using lag:0 also has the same source IP address as the uBFD configuration.
There is an operationally up interface with the same source IP address in the same routing instance.
Micro-BFD sessions share the resources from the pool used to identify MAC addresses belonging to the node, and the sessions must be processed by the applications on the node. Establishing a micro-BFD session results in one less resource available for other applications that use the pool, such as an IP interface, which is explicitly configured with a MAC address. On the 7210 SAS-R6 and 7210 SAS-R12, the MAC address resource is allocated per card, and is only allocated on cards with a LAG member port configured.
A remote IP address configured for a micro-BFD session must be the same IP address used to configure the micro-BFD session in the peer node.
The local IP address configured for micro-BFD should belong to the same routing instance as the IP interface configured for :0 LAG.