Alcatel-Lucent 7210 SAS M Interface Configuration Manual page 173

Ethernet Port Commands
- Ethernet cables need not be plugged in for copper ports.
• When the loop back command is enabled, ensure that Ethernet parameters such as, speed, duplex, auto-
negotiation and so on are not modified.
Notes: For port loopback with mac-swap:
• This command is available for testing VLL services and VPLS services only.
• When enabled, the command affects all services provisioned on the port.
• Before enabling this command, turn off all layer 2 and IP control protocols (such as LACP, EFM,
802.1x and so on) on the device and its peer to prevent errors such as protocol flaps due to timeout and
so on.When port loopback feature is to be used for multicast traffic with IGMP snooping enabled in the
service, the corresponding data path has to be statically created using static IGMP groups.
• When port loopback with mac-swap enabled, for unicast and unknown-unicast packets, if the packet
matches the configured source and destination MAC address it will be swapped and looped back in the
service. For broadcast and multicast packets, if the packet matches the configured source MAC address,
its source MAC address will be used as the destination MAC address and the system MAC address will
be the source MAC address. The packet is looped back in the service as a unicast packet. All other pack-
ets sent to the loopback port will be dropped. Since forwarding of these packets after loopback can
potentially cause network wide problems.
• For loop back to be functional, the following are not required:
- SFP or XFPs need not be inserted into the device.
- Ethernet cables need not be plugged in for copper ports.
• When the loop back is enabled, ensure that Ethernet parameters such as, speed, duplex, auto-negotiation
and so on are not modified.
• When the loopback is enabled, ensure that service parameter and attributes such as ingress qos policy,
accounting records, ingress/egress ACLs, and so on are not modified.
- With port loopback in use, the SAP ingress ACLs with IP-criteria is not recommended for use, since
only MAC addresses are swapped.
The recommended procedure for using port loopback with mac-swap is:
• Configure the service and SAP on which loopback is to be enabled.
• Configure the assigned loopback port to be used.
• Send bi-directional learning frames on the SAP under test and spoke or uplink from a traffic tester or
one can install static MAC for this purpose. Installing a static MAC is highly recommended, since the
recommended procedure for enabling port loopback is to shutdown the port –> enable loopback and
then execute no shutdown the port.
• Enable port loopback and specify the service, SAP, and the source MAC address (SA) and the destina-
tion MAC address (DA). All packets with source Mac matching SA are the only ones processed in the
context of the SAP on ingress after the loopback. Any other traffic, is dropped on ingress, to avoid
issues due to mac movement and flooding issues in other services/SAPs, since the whole port is in loop-
back.
• When the port is in loopback, software disable learning and aging on the specified SAP. Once the loop-
back configuration is removed for the port, then the software enables learning and aging for specified
SAP. Hence, port loopback with mac-swap cannot be used for learning or aging.
Page 168
Guide
7210 SAS M, T, X, R6, R12, Mxp Interface Configuration