Cisco Systems PA-2H manual Configuring Cyclic Redundancy Checks, Checking the Configuration

Configuring the HSSI Interfaces

Note If you want to configure cyclic redundancy checks (CRCs) for your port adapter, proceed to the next section, “Configuring Cyclic Redundancy Checks.” Otherwise, proceed to the “Checking the Configuration” section on page 7-8.

Configuring Cyclic Redundancy Checks

This section provides an example of how you can configure cyclic redundancy checks (CRCs) on the HSSI port adapter.

The HSSI port adapter uses a 16-bit CRC by default; it also supports a 32-bit CRC. CRC is an error-checking technique that uses a calculated numeric value to detect errors in transmitted data. The sender of a data frame divides the bits in the frame message by a predetermined number to calculate a remainder or frame check sequence (FCS). Before it sends the frame, the sender appends the FCS value to the message so that the frame contents are exactly divisible by the predetermined number. The receiver divides the frame contents by the same predetermined number that the sender used to calculate the FCS. If the result is not 0, the receiver assumes that a transmission error occurred.

To enable 32-bit CRC on an interface, enter configuration mode and specify the slot and port address of the HSSI, then enter the command crc32. Enter Ctrl-Zto exit from configuration mode.

In the example that follows, a single HSSI interface, on a VIP2 in interface processor slot 1, is configured for 32-bit CRC:

Router# configure terminal

Enter configuration commands, one per line. End with CNTL/Z.

Router(config)#

Router(config)# interface hssi 1/0/0

Router(config-int)# crc32

Ctrl-z

To disable CRC-32 and return to the default CRC-16 setting, specify the slot and port address and use the no crc32 command.

Note When enabling a 32-bit CRC on an interface, ensure that the remote device is also configured for a 32-bit CRC. Both the sender and the receiver must use the same CRC setting.

To check the interface configuration using show commands, proceed to the section “Checking the Configuration.” (For additional configuration options and instructions for configuring the HSSI port adapter on the VIP2, refer to the appropriate configuration publications listed in the “If You Need More Information” section on page vii.)

Checking the Configuration

After configuring the new interface, use the show commands to display the status of the new interface or all interfaces and the ping command to check connectivity.

7-8PA-2H Dual-Port HSSI Port Adapter Installation and Configuration