System information

Troubleshooting Serial Line Problems 15-327
Using Extended ping Tests
• debug frame-relay events—Determines whether exchanges are occurring between a router and a
Frame Relay switch.
• debug ppp negotiation—Shows Point-to-Point Protocol (PPP) packets transmitted during PPP
startup, where PPP options are negotiated.
• debug ppp packet—Shows PPP packets being sent and received. This command displays
low-level packet dumps.
• debug ppp errors—Shows PPP errors (such as illegal or malformed frames) associated with PPP
connection negotiation and operation.
• debug ppp chap—Shows PPP Challenge Handshake Authentication Protocol (CHAP) and
Password Authentication Protocol (PAP) packet exchanges.
• debug serial packet—Shows Switched Multimegabit Data Service (SMDS) packets being sent
and received. This display also prints error messages to indicate why a packet was not sent or was
received erroneously. For SMDS, the command dumps the entire SMDS header and some
payload data when an SMDS packet is transmitted or received.
Using Extended ping Tests
The ping command is a useful test available on Cisco internetworking devices as well as on many
host systems. In TCP/IP, this diagnostic tool is also known as an Internet Control Message Protocol
(ICMP) Echo Request.
Note The ping command is particularly useful when high levels of input errors are being registered
in the show interfaces serial display. See Figure 15-1.
Cisco internetworking devices provide a mechanism to automate the sending of many ping packets
in sequence. Figure 15-5 illustrates the menu used to specify extended ping options. This example
specifies 20 successive pings. However, when testing the components on your serial line, you should
specify a much larger number, such as 1000 pings.
Figure 15-5 Extended ping Specification Menu
Betelgeuse# ping
Protocol [ip]:
Target IP address: 129.44.12.7
Repeat count [5]: 20
Datagram size [100]: 64
Timeout in seconds [2]:
Extended commands [n]: yes
Source address:
Type of service [0]:
Set DF bit in IP header? [no]:
Validate reply data? [no]:
Data pattern [0xABCD]: 0xffff
Loose, Strict, Record, Timestamp, Verbose[none]:
Sweep range of sizes [n]:
Type escape sequence to abort.
Sending 20, 64-byte ICMP Echos to 129.44.12.7, timeout is 2 seconds:
Packet has data pattern 0xFFFF
!!!!!!!!!!!!!!!!!!!!
Success rate is 100 percent, round-trip min/avg/max = 1/3/4 ms
ping count
specification
Extended commands
selected option
Data pattern
specification