System information

Chapter 3 Initially Configuring the ATM Switch Router
Configuring Network Clocking
3-16
ATM Switch Router Software Configuration Guide
78-6277-03, Cisco IOS Release 12.0(13)W5(19)
When you specify a maximum diameter, you constrain the diameter of the spanning tree by specifying
the maximum number of hops between any two nodes that participate in the protocol. Each node must
be configured with the same maximum network diameter value for NCDP to operate correctly.
When you configure the NCDP as revertive, a clock source that is selected and then fails is selected
again once it has become operational for a period of time. On the Catalyst 8510 MSR and
LightStream 1010 platforms, if NCDP is configured to be revertive, a failed clocking source node after
a switchover is restored to use after it has been functioning correctly for at least 1 minute. On the
Catalyst 8540 MSR the failed source is restored after about 25 seconds. The network clock is, by
default, configured as nonrevertive. Nonrevertive prevents a failed source from being selected again.
Example
The following example shows setting the maximum number of hops to 11 and enabling revertive
behavior:
Switch(config)# ncdp max-diameter 11
Switch(config)# ncdp revertive
Configuring Optional NCDP Per-Interface Parameters
On a per-interface basis, you can enable or disable NCDP, specify the cost metric associated with the
port, and change the control virtual circuit used to transport protocol messages between adjacent
protocol entities. To change any of these parameters from their defaults, use the following commands
in interface configuration mode:
Example
The following example demonstrates setting the administrative weight on an interface:
Switch(config)# interface atm 0/0/0
Switch(config-if)# ncdp admin-weight 75
Displaying the NCDP Configuration
To display the NCDP configuration, use the following EXEC commands:
Command Purpose
ncdp admin-weight weight Specifies the cost metric associated with the given
port.
ncdp control-vc vpi vci Specifies the VPI/VCI values to use for control VCs.
The default is 0, 34.
no ncdp Disables NCDP on the interface.
Command Purpose
show ncdp path root Displays the NCDP clock path from the switch to the
root source.
show ncdp ports Displays NCDP port information.
show ncdp sources Displays NCDP clock sources configured on the
switch.