7705 SAR Interfaces
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Interface Configuration Guide
3HE 11011 AAAC TQZZA Edition: 01
When APS is enabled, the 7705 SAR constantly monitors the health of the APS links,
APS ports, and APS-equipped adapter cards. If the signal on the active (working)
port degrades or fails, the network proceeds through a predefined sequence of steps
to transfer (or switch over) traffic processing to the protection port. This switchover is
done very quickly to minimize lost traffic. Traffic is streamed from the protection port
until the working port fault is cleared, at which time the traffic may optionally be
reverted to the working port.
The 7705 SAR supports 1+1 single-chassis APS (SC-APS) and 1+1 multi-chassis
APS (MC-APS). In an SC-APS group, both the working and protection circuit must
be configured on the same node, whereas an MC-APS group can be on two separate
nodes, providing protection from node failure in addition to protection from link and
hardware failure.
Unidirectional and bidirectional modes are supported:
• unidirectional APS (Uni-1Plus1) — in unidirectional mode, only the port in the
failed direction switches to the protection port. Unidirectional mode is supported
only on SC-APS.
• bidirectional APS — in bidirectional mode, a failure in either direction causes
both the near-end and far-end equipment to switch to the protection port in each
direction. Bidirectional mode is the default mode and is supported on both
SC-APS and MC-APS.
For SC-APS and MC-APS with MEF 8 services where the remote device performs
source MAC validation, the MAC address of the channel group in each of the
redundant interfaces may be configured to the same MAC address using the mac
CLI command.
3.2.15.2 SC-APS
In an SC-APS group, both the working and protection circuits terminate on the same
node. SC-APS is supported in unidirectional or bidirectional mode on:
• 2-port OC3/STM1 Channelized Adapter cards for TDM CES (Cpipes) and TDM
CESoETH with MEF 8 with DS3/DS1/E1/DS0 channels
• 4-port OC3/STM1 / 1-port OC12/STM4 Adapter cards for MLPPP access ports
or TDM CES (Cpipes) and TDM CESoETH (MEF 8) access ports with DS1/E1
channels, or on a network port configured for POS
• 4-port OC3/STM1 Clear Channel Adapter cards network side (configured for
POS operation)
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