MC-LAG and Subscriber Routed Redundancy Protocol (SRRP) enable dual-homed links from any IEEE 802.1ax (formerly 802.3ad) standards-based access device (for example, a IP DSLAM, Ethernet switch or a Video on Demand server) to multiple Layer 2/3 or Layer 3 aggregation nodes. In contrast with slow recovery mechanisms such as Spanning Tree, multi-chassis LAG provides synchronized and stateful redundancy for VPN services or triple play subscribers in the event of the access link or aggregation node failing, with zero impact to end users and their services.
See the 7450 ESS, 7750 SR, and VSR Triple Play Service Delivery Architecture Guide for information about SRRP.