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.

     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
• There is congestion on a link or router along the route to the destination host, for example, caused by an unusually large file transfer which might indicate that the particular link or router has insufficient capacity

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

Example

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 ......+                
 ------------------------------------------------------------------------------
 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**