Diagnosing IP Networks › Test Connectivity

Test Connectivity

During problem diagnosis, you can use the PING command to do the following:

• Test whether a host is reachable through the network
• Determine the host name or IP address of a device
• Determine the network transit time for packets of varying sizes
• Determine whether all packets sent reached their destination

You can use a ping action in the following ways:

• Directly check the above information from the TCP/IP : Network Diagnosis Functions menu (/IPDIAG)
• Use the ping action against a host on a list or display; for example on a connection list
• Issue the PING command from the command line.

Perform a Ping

Performing a ping sends an Internet Control Message Protocol (ICMP) echo request that tests whether the remote host is reachable through the network and how long a return trip takes.

To test connectivity by sending a ping to a remote host

1. Enter /IPDIAG at the prompt.

   The TCP/IP : Network Diagnosis Functions menu appears.

2. Type P at the prompt and complete the following field:

   Host Name/Addr

   Specifies the name or IP address of the remote host you want to access.

   If you want to use a specific address of the local stack interface as the issuing point, select it in the Source Address field. If you want to trace the route through a specific physical interface, select it in the Interface field.

   Press Enter.

   The TCP/IP : Ping Result List appears.

Interpret Responses to a Ping

A ping is an end-to-end transmission between your system and a nominated remote host. When a ping is issued, it returns one of the following results:

• Successful
• Packets Lost
• No Response

To determine where on the network, problems such as packet loss, slow response times, or breaks in communication are occurring, you can perform a traceroute.

If, for example, you are investigating poor end-user response times, packet loss or high trip times may indicate that:

• An unexpected route to the host is being used.
• Congestion exists on a link or router along the route to the destination host. For example, if a particular link or router has insufficient capacity, an unusually large file transfer can cause congestion.

The response to a ping appears on the TCP/IP : Ping Result List. The list can be scrolled.

Example: Response to a Successful ping

The following shows an example of the response to a successful ping.

PROD--------------------- TCP/IP : Ping Result list ---------------------------
Command ===>                                                   Scroll ===> PAGE

 Target Host Name .... mercury.dept.company.com
        IP Address ... 192.168.2.66
 Count ............... 3__
 Timeout (seconds) ... 5__
 Packet Size ......... 256_
 Source Address ......+                
 Interface ...........+                 
 ------------------------------------------------------------------------------
 Result .............. Successful
 Min/Average/Max Time  10/12/14
 Packets sent ........ 3
         received .... 3
         % lost ...... 0
  Seq No.   Trip Time (ms)
     1      18
     2      14
     3      *
    **END**