Cabletron Systems 9032578-05 manual Configuring Automatic Protection Switching

Chapter 6: Packet-over-SONET Configuration Guide

2.Create a point-to-point interface with the interface create command, specifying the IP address and netmask for the interface on the SSR and the peer address of the other end of the connection:

interface create ip pos11 address-netmask 20.11.11.20/24 peer-address 20.11.11.21 port so.13.1

When you create the point-to-point interface as shown above, the SSR creates an implicit VLAN called “SYS_L3_<interface-name>.” In the above example, the SSR creates the VLAN ‘SYS_L3_pos11.’

3.If you want to increase the MTU size on a port, specify the parameter mtu with the

‘port set’ command and define a value up to 65535 (octets). See “Configuring Jumbo Frames” on page 80 for more information.

4.Specify the bit error rate thresholds, if necessary. See “Specifying Bit Error Rate Thresholds” for more information.

5.Modify any other PoS operating parameters, as needed. The following table lists the operating parameters that you can modify and the configuration commands that you use.

Table 4: PoS Optional Operating Parameters

Parameter	Default Value	Configuration Command
Framing	SONET	sonet set <port> framing sdhsonet
Loopback	Disabled	sonet set <port> loopback
Path tracing	(none)	sonet set <port> pathtrace
Circuit identifier	(none)	sonet set <port> circuit-id
Frame Check Sequence	32-bit	sonet set <port> fcs-16-bit
Scrambling	Enabled	sonet set <port> no-scramble

Configuring Automatic Protection Switching

Automatic protection switching (APS) provides a mechanism to support redundant transmission circuits between SONET devices. The SSR supports the following APS features:

•Linear network topology. Ring topologies are not supported.

•1+1 switching. Each working line is protected by one protecting line and the same signal is transmitted on both the working and protecting lines. The two transmission copies that arrive at the receiving end are compared, and the best copy is used. If there is a line failure or line degradation, the end node switches the connection over to the protecting line.

SmartSwitch Router User Reference Manual 59