Alcatel-Lucent 7710 SR OS, Руководство по настройке интерфейса

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Port Features
Page 62 7710 SR OS Interface Configuration Guide
APS on a Single Node
APS 1+1 can be implemented on a port by port basis. If all ports on an MDA or IOM need to be
protected then the ports on the MDA or IOM must be individually configured.
The working and protect lines are capable of being connected to:
• Two ports on the same MDA.
• Two ports on different MDAs but on the same IOM.
• Two ports on different MDAs on two different IOMs (installed in different slots).
If the working and protection channel are on the same MDA, protection is limited to the physical
port and the media connecting the two devices. If the different IOMs are used, protection extends
to IOM module failure.
Working and protection circuits can be connected to an ADM and serve as an access or network
port providing one or more services or network interfaces to the router. The APS-protected
SONET/SDH port may be further channelized, and may have channels bundled into either MLPPP
or an IMA bundle Bundle Protection Group. Any encapsulation type as supported by the MDA
supporting APS can be configured including PPP encapsulations, ATM, FR, Cisco HDLC.
IMA APS protection is supported only when the router is connected through ADM to another
equipment running a single IMA instance at the far end. By design, IMA APS implementation is
expected to keep IMA protocol up as long as the far end device can tolerate frame loss.
Similarly, the PPP protocol state machine for PPP channels and MLPPP bundles remains UP when
a switchover occurs between the working and protect circuits.
The ADM or compatible head-end transmits a valid data signal to both the working and protection
circuits. The signal on the protect line will be ignored until the working channel fails or degrades
to the degree that requires a switchover to the protect channel. When the switchover occurs all
services including all their QoS and filter policies are activated on the protection channel.
Removing or Failure of a Protect MDA/CMA
The detection of an CMA/MDA removal or an CMA/MDA failure can take additional time. This
can affect the APS switchover time upon the removal or failure of a protection MDA. If the
removal is scheduled during maintenance, it is recommended that the port and/or protect circuit be
shutdown first to initiate an APS switchover before the MDA maintenance is performed.