Network Card User Manual

Configuring the HSSI Interfaces
PA-2H Dual-Port HSSI Port Adapter Installation and Configuration
7-8
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-Z to 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.