This section describes the Multi-Chassis LAG (MC-LAG) concept. MC-LAG is an extension of a LAG concept that provides node-level redundancy in addition to link-level redundancy provided by ‟regular LAG”.
MC-LAG is supported on all 7210 SAS platforms as described in this document, except those operating in access-uplink mode.
Typically, MC-LAG is deployed in a network-wide scenario and provides redundant connection between different end points. The whole scenario is then built by a combination of different mechanisms (for example, MC-LAG and redundant pseudowire to provide end-to-end (e2e) redundant point-to-point (p2p) connection or dual homing of CPE devices in Layer 2/3 VPNs).
The 7210 SAS platforms configured in access-uplink mode cannot peer with an MC-LAG-enabled node because it does not implement MC-LAG protocol; a 7210 SAS-T in access-uplink mode cannot provide MC-LAG server functionality. Instead they can be used as MC-LAG clients, with the platforms connected to a head-end node that support MC-LAG server functionality. These platforms connect to the head-end node using LAG.