Cisco ASR 900 Series Configuration Guide

1+1 MSP
In the 1+1 architecture, there is one working interface (circuit) and one protection interface, and the same
payload from the transmitting end is sent to both the receiving ends. The receiving end decides which interface
to use. The line overhead (LOH) bytes (K1 and K2) in the SDH frame indicate both status and action.
The protection interfaces need to be configured with an IP address of the chassis that has the working interface,
using MSP commands. The MSP Protect Group Protocol, which runs on top of UDP, provides communication
between the process controlling the working interface and the process controlling the protection interface.
Using this protocol, interfaces can be switched because of a chassis failure, degradation or loss of channel
signal, or manual intervention. In bidirectional mode, the receive and transmit channels are switched as a pair.
Two SDH connections are required to support MSP.
The following option is available for linear bidirectional 1+1 MSP:
• Revertive option — For any failure on working line, the software switches to protection line and when
the working line recovers, it waits based on the revertive timer and reverts back to working line as active
link.
• Non-revertive option — When the signal fails, the software switches to the protection line and does not
automatically revert back to the working line. This is the default option.
The following features are supported on 1+1 MSP:
•
SDH PW (SAToP or CEP)
•
SDH local connect
Benefits of MSP
The following lists the benefits of MSP:
•
MSP performs switchovers with minimal loss of data, and time-consuming reroutes are avoided.
•
There is no visibility that a failure has occurred beyond the network element in which it is residing; other
nodes are not affected by the failure.
•
Implementation of MSP guards a network against complex restarts and resynchronizations since failures
are isolated to a local device.
•
With MSP, the effect of a failure is greatly minimized, and a fast switchover guarantees minimal effect
on the network.
Restrictions for MSP
•
MSP is supported on all the ports except on the 8th port with STM-64.
•
Loopback, BERT, ACR and DCR, and Clocking should be configured on physical member controllers.
1-Port OC-192 or 8-Port Low Rate CEM Interface Module Configuration Guide, Cisco IOS XE Everest 16.7.x
(Cisco ASR 900 Series)
114
Configuring MSP on 1-Port OC192/STM-64 or 8-Port OC3/12/48/STM-1/-4/-16 Module
1+1 MSP

Cisco ASR 900 Series Specifications

General

Brand	Cisco
Model	ASR 900 Series
Category	Network Router
Language	English