Practical Industrial Data Networks:Design, Installation and ...

374 Practical Industrial Data Networks: Design, Installation and TroubleshootingNote1. During boot-up, there may be errors displayed stating that there is alreadyanother computer on the network with the same IP address, and allnetworking services would be disabled. Follow the procedure described aboveand choose another IP address and restart.2. Some users may not be able to browse the Network Neighborhood if the userhas not logged in with an appropriate username and password at the time ofboot-up. Log-off and log-on as a valid user.3. Others may not be able to either see their own host computer or other’s hostcomputers. Not sharing any resource leads to this problem. Follow theprocedure described in Practical-1 and share some resource.ConclusionNotice that even though we enter only one ping command, we receive four replies. This isdue to the default programmed within the ping.exe executable that instructs to send out 4requests one after another. The ping command sends out 32 bytes of data to the remotehost and therefore we observe bytes=32. The time=1 ms denotes the total round trip timetaken for the ping message to be transmitted and a reply to be received, in milliseconds.TTL=255, indicates that the replying host is permitting this reply to traverse through atotal of 255 networks. Why do we need to limit the number of networks traversed?At the DOS prompt type ping without any options and it will display a list of thevarious switches that are available to customize the ping message.Practical 16: Using ICMP echo messages (PING)OverviewThe Internet control message protocol (ICMP) is the protocol used by the TCP/IPnetwork layers to communicate with each other, monitor one another and exchangeinformation. This practical reviews the workings of the PING command.ObjectivesThis practical shows you how to use ICMP echo messages using the PING commandover a TCP/IP network. This is a very important troubleshooting tool as it allows us tocheck whether a particular computer is accessible on the network.Hardware/software requiredThe hardware required for this practical is as follows:• Two or more personal computers or laptops.• One network interface card (NIC) or Ethernet card per computer.• One unshielded twisted pair (UTP) patch cable per computer.• UTP hub(s) with requisite number of ports.• Power supplies for the various computers and hubs as required.• One additional Ethernet card with a UTP patch cable.The software required is as follows:• All the computers loaded with Windows 98 second edition operating system(Windows 95, NT, 2000 and ME will also do, this book shall refer toWindows 98 SE).