Brocade Multi-Service IronWare Switching Configuration Guide (Supporting R05.6.00) - Manual (Page 567)

Multi-Service IronWare Switching Configuration Guide 537
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ERP commands
15
Configuring dual-end blocking
You can configure dual-end blocking to optimize your ERP configuration. The RPL node must be
adjacent to the RPL owner.
When you configure the RPL on an ERN that is adjacent to the RPL owner, you are enabling the
dual-end blocking feature and changing the ERN’s role to that of RPL node. You configure the RPL
node with the rpl command. Before configuring dual-end blocking, you must verify that the RPL
node is actually the correct peer and obtain the RPL link settings; an incorrect setting will cause
incorrect port blocking.
NOTE
The RPL node must be a peer of the RPL owner, and the RPL must be configured on this peer;
otherwise, the device will perform incorrect port blocking behavior.
Syntax: [no] rpl [vlan vlan-id | esi esi_name vlan vlan_id slot/number ]
Configuring the guard timer
The guard timer prevents ERNs from acting upon outdated R-APS messages and prevents the
possibility of forming a closed loop. The guard timer enforces a period during which an ERP
topology ignores received R-APS.
This timer period should always be greater than the maximum expected forwarding delay in which
an R-APS message traverses the entire ring. The longer the period of the guard timer, the longer an
ERN is unaware of new or existing relevant requests transmitted from other ERN and, therefore,
unable to react to them.
The guard timer is used in every ERN, once a guard timer is started, it expires by itself. While the
guard timer is running, any received R-APS request/state and Status information is blocked and not
forwarded to the priority logic. When the guard timer is not running, the R-APS request/state and
status information is forwarded unchanged.
NOTE
The Release 5.1.0 implementation of the guard timer differs from the ITU-T G.8032 document. The
standard defines the guard timer period as configurable in 10 ms increments from 10 ms to 2000
ms (2 seconds) with a default value of 500 ms.
The guard timer is activated when an ERN receives an indication that a local switching request,
such as a clear signal fail, manual switch, or forced switch, is cleared.
The guard timer can be configured in 100ms increments from 1200ms to 4000ms (4 seconds);
the default value is 1500ms (1.5 seconds). The guard timer cannot be stopped manually.
Syntax: guard-time time-value
Configuring and clearing the wait to restore timer
For SF recovery situations, you can configure the wait to restore (WTR) timer on the RPL owner to
prevent frequent operation of the protection switching due to the detection of intermittent signal
failures. When recovering from a Signal Failure, the WTR timer must be long enough to allow the
recovering network to become stable.