Introduction 1-23
Network Synchronization
Cost-Based AutoRoute Commands
The following switched software Command Line Interface (CLI) commands are used for cost-based
route selection:
• cnfcmparm - enables cost-based route selection. This is a super-user command used to configure
all AutoRoute parameters. By default cost-based route selection is disabled. Enabling or
disabling cost-based route selection can be done at any time. Each connection routing cycle uses
whichever algorithm is enabled when the cycle begins. The configuration is node-based, not
network-based, which allows each node to have its own route selection algorithm.
Enabling cost-based route selection automatically enables cache usage. Disabling cost-based
route selection automatically disables cache usage. Cache usage may also be independently
enabled or disabled.
• cnftrk - configures the administrative cost for a trunk. Both physical and virtual trunks have the
cost attribute. Each trunk has a cost ranging from 1 (lowest) to 50 (highest). The default cost is
10 upon trunk activation.
The cost can be configured from either end of the trunk. The cost can be changed before or after
the trunk has been added to the network. The cost can also be changed after connections have
been routed over the trunk. Any cost change is updated network-wide. Every node in the network
stores the cost of every trunk in the network. This knowledge is required for successful
source-based routing.
• cnfrtcost - new command which configures the cost cap for a connection. This command is valid
only at the node where the connection is added.
• cnfsysparm - configures the delay cost cap for all delay sensitive connections in the network.
This command was not modified in Release 9.0.
• dspcon - displays the maximum and current costs for a connection route
• dspload - displays the administrative cost and queue delay for a network trunk
• dsprts - displays the current costs for all connection routes
• dsptrkcnf - displays the configured cost of a trunk
The Cisco WAN Switching Command Reference contains detailed information about the use of BPX
switch commands.
Network Synchronization
Cisco WAN switching cell relay networks use a fault-tolerant network synchronization method of
the type recommended for Integrated Services Digital Network (ISDN). Any circuit line, trunk, or
an external clock input can be selected to provide a primary network clock. Any line can be
configured as a secondary clock source in the event that the primary clock source fails.
All nodes are equipped with a redundant, high-stability internal oscillator that meets Stratum 3
(BPX) or Stratum 4 requirements. Each node keeps a map of the network's clocking hierarchy. The
network clock source is automatically switched in the event of failure of a clock source.
There is less likelihood of a loss of customer data resulting from re-frames that occur during a clock
switchover or other momentary disruption of network clocking with cell-based networks than there
is with traditional TDM networks. Data is held in buffers and packets are not sent until a trunk has
regained frame synchronism to prevent loss of data.
