Specifications

Configuring the HSSI Interfaces
PA-H HSSI Port Adapter Installation and Configuration
8-8
8-8
Step 8 Write the new configuration to nonvolatile memory as follows:
Router# copy running-config startup-config
[OK]
Router#
Note If you want to configure cyclic redundancy checks (CRCs) for your HSSI, proceed to the next
section, “Configuring Cyclic Redundancy Checks.” Otherwise, proceed to the “Checking the
Configuration” section on page 8-8.
Configuring Cyclic Redundancy Checks
This section provides an example of how you can configure cyclic redundancy checks (CRCs) on the
PA-H.
The PA-H 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 a 32-bit CRC on an interface, enter configuration mode and specify the slot and port
address of the HSSI, and then enter the command crc32. Enter Ctrl-Z to exit from configuration
mode.
In the following example, a single HSSI interface on a VIP2 in interface processor slot 1 is
configured for a 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 next section “Checking
the Configuration.” (For additional configuration options and instructions for configuring the PA-H
on the VIP2, refer to the appropriate configuration publications listed in the “Related
Documentation” section on page vi.)
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.