Foundry Networks Switch and Router Installation And Configuration Manual page 170

Foundry Switch and Router Installation and Configuration Guide
Disabling or Reenabling Keepalive Messages
You can disable or reenable a POS interface to send keepalive messages to the POS interface at the other end of
the link. Keepalive messages are enabled by default.
The message interval is 10 seconds and is not configurable. Every ten seconds, the POS interface sends a
keepalive message addressed to the POS interface at the other end of the connection. The timeout is 30
seconds. If the other interface (remote end of the connection) does not respond as expected to a keepalive
message after 30 seconds, the Layer 3 Switch takes the local interface down. The link remains up but the POS
interface is down. If the Layer 3 Switch receives a keepalive response from the other interface, the Layer 3 Switch
brings the local interface back up.
For PPP connections, one or both interfaces can send the keepalive messages. For HDLC connections, both
interfaces must send keepalive messages. If the keepalive messages are enabled on only one interface in an
HDLC connection, the interface will conclude based on the absence of keepalive messages from the other
interface that the connection is down and will take the local interface down.
To disable or re-enable the POS keepalive messages, use the following method:
USING THE CLI
To disable keepalive messages on POS interface 2/1, enter the following commands:
BigIron(config)# interface pos 2/1
BigIron(config-posif-2/1)# no keepalive
BigIron(config-posif-2/1)# write memory
Syntax: [no] keepalive
To reenable the messages, enter the following commands:
BigIron(config)# interface pos 2/1
BigIron(config-posif-2/1)# keepalive
BigIron(config-posif-2/1)# write memory
Changing the Bandwidth
Depending on the POS module you have installed, the interfaces operate at 155 Mbps or 622 Mbps by default.
• The ports on model number B2P622 run at 622 Mbps by default. If needed, you can reduce the port
bandwidth to 155 Mbps on an individual port basis.
• The port bandwidth on other models is not configurable.
To change the bandwidth of a POS port, use the following method.
USING THE CLI
To change the bandwidth of POS interface 2/1 from 622 Mbps to 155 Mbps, enter the following commands:
BigIron(config)# interface pos 2/1
BigIron(config-posif-2/1)# bandwidth 155
BigIron(config-posif-2/1)# write memory
Syntax: bandwidth 155 | 622
The 155 and 622 parameters specify how many megabits per second the port can transmit.
To change the port bandwidth of POS interface 2/1 back to 622 Mbps, enter the following commands:
BigIron(config)# interface pos 2/1
BigIron(config-posif-2/1)# bandwidth 622
BigIron(config-posif-2/1)# write memory
Changing the POS Flags
The POS flags set POS "overhead" values, which are values in the packet headers that identify the packet
payload content type, the packet's compatibility with some other SDH devices, and the frame type.
6 - 8 December 2000