3Com 3036, Configuration Manual

Page: 368 / 762

364 C
HAPTER
22: C
ONFIGURING
IP P
ERFORMANCE
Troubleshooting IP
Performance
Configuration
Fault 1: TCP and UDP are created upon IP protocol, and IP is able to provide
data packet transmission. However, TCP and UDP protocols do not work
normally
Troubleshooting: Turn on corresponding debugging switches to check the
debugging information
■
Use the
debugging udp
command to turn on the UDP debugging switch, and
trace the UDP data packet. When the router sends or receives UDP data
packets, the packet content format can be displayed in real time, so problems
can be located.
The UDP data packet format is as follows:
UDP output packet:
Source IP address: 202.38.160.1
Source port: 1024
Destination IP Address 202.38.160.1
Destination port: 4296
■
Use the
debugging tcp
command to turn on the TCP debugging switch, and
trace the TCP data packet. TCP has two data packet format options: one is to
debug and trace the receiving/sending of TCP packets in all TCP connections
with this equipment as one end. The specific operation is as follows:
[Router] info-center enable
[Router] debugging tcp packet
The TCP packets received or sent can be checked in real time, and the specific
format is as follows:
TCP output packet:
Source IP address: 202.38.160.1
Source port: 1024
Destination IP Address 202.38.160.1
Destination port: 4296
Sequence number: 4185089
Ack number: 0
Flag: SYN
Packet length: 60
Data offset: 10
Another data packet format is to debug and trace packets with SYN, FIN or RST
setting.
[Router] info-center enable
[Router] debugging tcp event
The TCP packets received or sent can be checked in real time, with the same
packet format as above.