T1/E1 Line Card Redundancy (LCR) uses redundant adapter cards to protect T1/E1 services in case of hardware failures. T1/E1 LCR provides protection against adapter card or node failures. When T1/E1 LCR is used in conjunction with pseudowire redundancy, the network path between the endpoints is also protected. Protection is provided specifically for Cpipe services at the clear channel level and at the channelized level.
When T1/E1 LCR is enabled, the 7705 SAR constantly monitors the health of the adapter cards. If the active (working) adapter card fails (for example, because a card has been removed or due to a bus error), the system proceeds through a predefined sequence of steps to transfer (or switch over) traffic processing to the protection MDA. This switchover is done very quickly to minimize traffic loss. Traffic is moved to the protection adapter card until the fault on the working adapter card is cleared, at which time the traffic may optionally revert to the working adapter card.
T1/E1 LCR is supported on the following cards on the 7705 SAR-8 Shelf V2 and the 7705 SAR-18:
16-port T1/E1 ASAP Adapter card
32-port T1/E1 ASAP Adapter card
T1/E1 LCR includes support for single-chassis LCR (SC-LCR) and multi-chassis LCR (MC-LCR). In an SC-LCR group, both the working and protection adapter cards must be configured on the same node. In an MC-LCR group, the working adapter card and protection adapter card are configured on two separate nodes, providing protection from node failure in addition to protection from adapter card hardware failure.