Cisco Systems OC-12/STM-14 Verifying Local and Remote DS3 Port Settings, Selecting a DSU Mode

Cisco IOS Software Configuration for the 1-Port Channelized OC-12/STM-4 (DS3) Line Card

How to Configure the 1-Port Channelized OC-12/STM-4 (DS3) Line Card

The Cisco Remote Connection Management feature uses two Cisco-proprietary DS3 C-bit parity Far-End Alarm and Control (FEAC) messages that are not used in the American National Standards Institute (ANSI) standard. Table 4 explains the commands that generate the FEAC messages.

Table 4	Far-End Alarm and Control Messages
Confirmation Message		FEAC Code	Default Value	Commands
DEFAULT_SUBRATE_CONFIG		0x0CFF	fullrate	Router (config-if)# dsu remote fullrate
REMOVE_DEFAULT_SUBRATE_CONFIG		0x08FF	user-configured	Router (config-if)# dsu remote fullrate

Note The local port and the remote port must have matching configurations.

The following sections explain how to use Cisco IOS commands for Cisco Remote Connection Management. Table 3 lists the command parameters.

Verifying Local and Remote DS3 Port Settings

You can use telnet to determine the DSU mode settings on the remote DS3 port. Once you verify the remote DS3 port settings, you can change the local configuration parameters so that DSU mode settings are the same on both the local and remote DS3 ports. You can set the DSU bandwidth to accept or reject the incoming remote requests from the local DS3 port by entering the dsu remote accept interface configuration command.

Selecting a DSU Mode

The DSU mode supports three third-party DSU vendors—Digital-Link, Kentrox, and Larscom—and the default DSU mode, Cisco. If you use a DSU to make the connection between the Cisco 12000 Series Router and another device, the local DS3 port configuration must match the remote DS3 port configuration. Therefore, if the remote DS3 port uses the Kentrox vendor, a request is sent to the local DS3 port to change the DSU mode to Kentrox, by manually entering the dsu mode configuration command and specifying the Kentrox DSU. If you make a direct connection between a Cisco 12000 Series Router and another device, you can use the default DSU mode, Cisco. See Figure 2 for configuration examples.

Setting the Sending and Receiving Rate

The local and remote DS3 ports must also agree on whether to use a subrate or fullrate sending and receiving rate, because the speed of the sending and receiving rate is regulated by the DSU mode. If the sending and receiving rates do not match, they will not work. Subrates are specific to DSU modes and must be configured appropriately. The subrate sending and receiving rate is slower and less expensive than the faster, more expensive, fullrate. You can synchronize the local and remote DS3 ports sending and receiving rates by entering the dsu remote interface configuration command.

Configuring the DSU Bandwidth Range

The DSU bandwidth range is from 0 to 44210 kbps. The local port and the remote port must have matching configurations. Therefore, if you reduce the effective bandwidth to 3000 on the local port, you must do the same on the remote port by entering the dsu bandwidth interface configuration command.

Cisco IOS Release 12.0(8)S

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