SYSK 303: Troubleshooting Connectivity Issues

  • Article

Did you know that you can use a utility called pathping to get information network latency and network loss at intermediate hops between a source and destination?

Pathping works by sending multiple ‘echo request’ messages to each router between a source and destination over a period of time and then computes results based on the packets returned from each router. Because the results include the degree of packet loss at any given router or link, you can determine which routers or subnets might be having network problems.

 

Note: this command is available only if the Internet Protocol (TCP/IP) protocol is installed as a component in the properties of a network adapter in Network Connections.

 

Here is the syntax (parameters are case-sensitive):

 

pathping [-n] [-h MaximumHops] [-g HostList] [-p Period] [-q NumQueries [-w Timeout] [-T] [-R] [TargetName]

 

-n : Prevents pathping from attempting to resolve the IP addresses of intermediate routers to their names. This might expedite the display of pathping results.

 

-h MaximumHops : Specifies the maximum number of hops in the path to search for the target (destination). The default is 30 hops.

 

-g HostList : Specifies that the Echo Request messages use the Loose Source Route option in the IP header with the set of intermediate destinations specified in HostList. With loose source routing, successive intermediate destinations can be separated by one or multiple routers. The maximum number of addresses or names in the host list is 9. The HostList is a series of IP addresses (in dotted decimal notation) separated by spaces.

 

-p Period : Specifies the number of milliseconds to wait between consecutive pings. The default is 250 milliseconds (1/4 second).

 

-q NumQueries : Specifies the number of Echo Request messages sent to each router in the path. The default is 100 queries.

 

-w Timeout : Specifies the number of milliseconds to wait for each reply. The default is 3000 milliseconds (3 seconds).

 

-T : Attaches a layer-2 priority tag (for example, 802.1p) to the Echo Request messages that it sends to each of the network devices along the route. This helps to identify network devices that do not have layer-2 priority capability. This switch is used to test for Quality of Service (QoS) connectivity.

 

-R : Determines whether each network device along the route supports the Resource Reservation Protocol (RSVP), which allows the host computer to reserve a specified amount of bandwidth for a data stream. This switch is used to test for Quality of Service (QoS) connectivity.

 

TargetName : Specifies the destination, which is identified either by IP address or host name.

 

/? : Displays help at the command prompt.

 

 

For more information, check out http://www.microsoft.com/resources/documentation/windows/xp/all/proddocs/en-us/pathping.mspx?mfr=true, which was the primary source for this post.