Installation guide

5-30 Cisco 4000 Series Installation Guide
Checking the Router Configuration
Configuring CRC-4 for E1-G.703/G.704 Interfaces
CRC-4 is a 4-bit error checking technique that uses a calculated numeric value to perform
an ongoing data integrity check and detect errors in transmitted data. The E1-G.703/G.704
network processor module supports CRC in framed mode only. By default, CRC-4 is not
enabled.
To enable CRC-4 on the E1 interface, specify the port address of the interface followed by
the command crc4. Press Ctrl-Z after altering the configuration and before exiting the
configuration mode. In the example that follows, serial port 3 on an E1-G.703/G.704
network processor module is configured for CRC:
Router# configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
Router (config)# interface serial 3
(config-if)# crc4
(config-if)# ^Z
To disable CRC and return to the default of no CRC error checking, specify the port and
use the no crc4 command. For complete command descriptions and instructions refer to the
Cisco IOS configuration guides and command references.
Checking the Router Configuration
When you have configured the serial interfaces, use the show interface command to check
the network interface statistics. Options to the show interface command include the type
of interface (for example, serial), and the unit number of the interface. The following
example shows the output of show interface serial 0:
router> show interface serial 0
Serial 0 is up, line protocol is up
Hardware is HD64570
Internet address is 193.195.74.236, subnet mask is 255.255.255.248
MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, rely 255/255, load 1/255
Encapsulation HDLC, loopback not set, keepalive not set
Last input 0:00:01, output 0:00:10, output hang never
Last clearing of "show interface" counters never
Output queue 0/40, 0 drops; input queue 0/75, 0 drops
Five minute input rate 0 bits/sec, 0 packets/sec
Five minute output rate 0 bits/sec, 0 packets/sec
2922 packets input, 5844 bytes, 0 no buffer