Alcatel-Lucent 7710 SR OS, Interface Configuration Manual

Page: 64 / 436

Port Features
Page 64 7710 SR OS Interface Configuration Guide
Switch-Over Process for Transmitted Data
For packets arriving on all interfaces that need to be transmitted over APS protected interfaces, the
next hop associated with all these interfaces are programmed in all Flexible Fast-Path complexes
in each MDA with a logical next-hop index. This next hop-index identifies the actual next-hop
information used to direct traffic to the APS working channel on IOM-1 / MDA-1.
All Flexible Fast-Path complexes in each MDA are also programmed with next hop information
used to direct traffic to the APS protect channel on IOM-2 / MDA-1. When the transmitted data
needs to be switched from the working to the protect channel, only the relevant next hop indexes
need to be changed to the pre-programmed next-hop information for the protect channel on IOM-2
/ MDA-1.
Although the control CPM on the SF/CPM blade initiates the changeover between the working to
protect channel, the changeover is transparent to the upper layer protocols and service layers that
the switchover occurs.
Physical link monitoring of the link is performed by the CPU on the relevant IOM for both
working and protect channel.
Switch-Over Process for Received Data
The Flexible Fast-Path complexes for both working and protect channels are programmed to
process ingress. The inactive (protect) channel however is programmed to ignore all packet data.
To perform the switch-over from working channel to the protect channel the Flexible Fast-Path
complex for the working channel is set to ignore all data while the Flexible Fast-Path complex of
the protect channel will be changed to accept data.
APS Switch After CFM Switchover
Immediately after a CFM switchover, there is a period during which the former standby CFM that
is transitioning to the active state needs to audit the APS CFM.