System information

Using Extended ping Tests
Book Title
15-328
In general, perform serial line ping tests as follows:
Step 1 Put the CSU or DSU into local loopback mode.
Step 2 Configure the extended ping command to send different data patterns and packet sizes.
Figure 15-6 and Figure 15-7 illustrate two useful ping tests, an all-zeros 1500-byte ping
and an all-ones 1500-byte ping, respectively.
Step 3 Examine the show interfaces serial command output (see Figure 15-1) and determine
whether input errors have increased. If input errors have not increased, the local hardware
(DSU, cable, router interface card) is probably in good condition.
Assuming that this test sequence was prompted by the appearance of a large number of
CRC and framing errors, a clocking problem is likely. Check the CSU or DSU for a
timing problem. See the section “Troubleshooting Clocking Problems” later in this
chapter.
Step 4 If you determine that the clocking configuration is correct and is operating properly, put
the CSU or DSU into remote loopback mode.
Step 5 Repeat the ping test and look for changes in the input error statistics.
Step 6 If input errors increase, there is either a problem in the serial line or on the CSU/DSU.
Contact the WAN service provider and swap the CSU or DSU. If problems persist,
contact your technical support representative.
Figure 15-6 All-Zeros 1500-Byte ping Test
yowzers#ping
Protocol [ip]:
Target IP address: 192.169.51.22
Repeat count [5]: 100
Datagram size [100]: 1500
Timeout in seconds [2]:
Extended commands [n]: y
Source address: 192.169.51.14
Type of service [0]:
Set DF bit in IP header? [no]:
Validate reply data? [no]:
Data pattern [0xABCD]: 0x0000
Loose, Strict, Record, Timestamp, Verbose[none]:
Sweep range of sizes [n]:
Type escape sequence to abort.
Sending 100, 1500-byte ICMP Echos to 192.169.51.22, timeout is 2 seconds:
Packet has data pattern 0x0000
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Success rate is 100 percent (100/100), round-trip min/avg/max = 4/6/8 ms
yowzers#
1500 byte
packet size
All zeros
ping