CPE ping has been supported for VPLS services since Release 3.0 of SR OS. It enables the connectivity of the access circuit between a VPLS PE and a CPE to be tested, even if the CPE is unmanaged and, therefore, the service provider cannot run standardized Ethernet OAM to the CPE. The command cpe-ping for a specific destination IP address within a VPLS is translated into a mac-ping toward a broadcast MAC address. All destinations within the VPLS context are reached by this ping to the broadcast MAC address. At all these destinations, an ARP is triggered for the specific IP address (with the IP destination address equal to the address from the request, mac-da equal to all ones, mac-sa equal to the CPM-mac-address and the IP source address, which is the address found in the request). The destination receiving a response replies back to the requester.
Release 10.0 extended the CPE ping command for local, distributed, and PBB Epipe services provisioned over a PBB VPLS. CPE ping for Epipe implements an alternative behavior to CPE ping for VPLS that enables fate sharing of the CPE ping request with the Epipe service. Any PE within the Epipe service (the source PE) can launch the CPE ping. The source PE builds an ARP request and encapsulates it to be sent in the Epipe as if it came from a customer device by using its chassis MAC as the source MAC address. The ARP request then egresses the remote PE device as any other packets on the Epipe. The remote CPE device responds to the ARP and the reply is transparently sent on the Epipe toward the source PE. The source PE then looks for a match on its chassis MAC in the inner customer DA. If a match is found, the source PE device intercepts this response packet.
This method is supported regardless of whether the network uses SDPs or SAPs. It is configured using the existing oam>cpe-ping CLI command.