Port loopback for Ethernet ports
The 7210 SAS supports port loopback for Ethernet ports. There are two flavors of port loopback commands - port loopback without mac-swap and port loopback with mac-swap. Both these commands are helpful for testing the service configuration and measuring performance parameters such as throughput, delay, and jitter on service turn-up. Typically, a third-party external test device is used to inject packets at desired rate into the service at a central office location.
The following sections describe the port loopback functionality.
Port loopback without MAC swap
Port loopback without MAC swap is supported on all 7210 SAS platforms as described in this document.
When the port loopback command is enabled, the system enables PHY/MAC loopback on the specified port. All the packets are sent out the port configured for loopback and received back by the system. On ingress to the system after the loopback, the node processes the packets as per the service configuration for the SAP.
This is recommended for use with only Epipe services. This command affects all the services configured on the port, therefore the user is advised to ensure all the configuration guidelines mentioned for this feature in the command description are followed.
Port loopback with MAC swap
Port loopback with MAC swap is only supported on the 7210 SAS-D and 7210 SAS-Dxp.
The 7210 SAS provides port loopback support with MAC swap. When the port loopback command is enabled, the system enables PHY/MAC loopback on the specified port. All the packets are sent out the port configured for loopback and received back by the system. On ingress to the system after the loopback, the node swaps the MAC addresses for the specified SAP and the service. It only processes packets that match the specified source MAC address and destination MAC address, while dropping packets that do not match. It processes these packets as per the service configuration for the SAP.
This is recommended for use with only VPLS and Epipe services. This command affects all the services configured on the port, therefore the user is advised to ensure all the configuration guidelines mentioned for this feature in the command description are followed.
Per-SAP loopback with MAC swap
Per-SAP loopback with MAC swap is only supported on the 7210 SAS-K 2F1C2T, 7210 SAS-K 2F6C4T, and 7210 SAS-K 3SFP+ 8C.
The 7210 SAS-K 2F1C2T, 7210 SAS-K 2F6C4T, and 7210 SAS-K 3SFP+ 8C provide per-SAP loopback support with MAC swap. When the SAP loopback command is enabled, all the packets that are sent out the SAP configured with loopback are looped back at the egress of the SAP back into the ingress of the SAP. The node swaps the MAC addresses before the packet hits the ingress of the SAP. After it is received back at SAP ingress, it processes these packets as per the service configuration for the SAP. Only traffic sent out of the test SAP is looped back. The loopback does not affect other SAPs and services configured on the same port. Per-SAP loopback is supported for use with both VPLS and Epipe services.