Quick Reference Guide

PowerConnect B-Series TI24X Configuration Guide 213
53-1002269-02
Metro Ring Protocol (MRP)
8
Changing the hello and preforwarding times
You also can change the RHP hello time and preforwarding time. To do so, enter commands such
as the following.
PowerConnect(config-vlan-2-mrp-1)# hello-time 200
PowerConnect(config-vlan-2-mrp-1)# preforwarding-time 400
These commands change the hello time to 200 ms and change the preforwarding time to 400 ms.
Syntax: [no] hello-time <ms>
Syntax: [no] preforwarding-time <ms>
The <ms> specifies the number of milliseconds. For the hello time, you can specify from 100 –
1000 (one second). The default hello time is 100 ms. The preforwarding time can be from 200 –
5000 ms, but must be at least twice the value of the hello time and must be a multiple of the hello
time. The default preforwarding time is 300 ms. A change to the hello time or preforwarding time
takes effect as soon as you enter the command.
Configuration notes
The preforwarding time must be at least twice the value of the hello time and must be a
multiple of the hello time.
If UDLD is also enabled on the device, Dell recommends that you set the MRP preforwarding
time slightly higher than the default of 300 ms; for example, to 400 or 500 ms.
You can use MRP ring diagnostics to determine whether you need to change the hello time and
preforwarding time. Refer to “Using MRP diagnostics”.
Using MRP diagnostics
The MRP diagnostics feature calculates how long it takes for RHP packets to travel through the ring.
When you enable MRP diagnostics, the software tracks RHP packets according to their sequence
numbers and calculates how long it takes an RHP packet to travel one time through the entire ring.
When you display the diagnostics, the CLI shows the average round-trip time for the RHP packets
sent since you enabled diagnostics. The calculated results have a granularity of 1 microsecond.
Enabling MRP diagnostics
To enable MRP diagnostics for a ring, enter the following command on the master node, at the
configuration level for the ring.
PowerConnect(config-vlan-2-mrp-1)# diagnostics
Syntax: [no] diagnostics
NOTE
This command is valid only on the master node.
Displaying MRP diagnostics
To display MRP diagnostics results, enter the following command on the master node.