Cisco Systems 8600 Series manual Network Synchronization, Cost-Based AutoRoute Commands

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.

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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.

Introduction 1-23