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TITLE: Internet Control Message Protocol (ICMP) (Ping) Is Routing , Transmission Control Protocol (TCP) Is Not. Situation:A dial up user using Trumpet or MS-Windows '95 connecting to a Lucent PortMaster (TM) is "hanging" up. Symptom:ICMP traffic traverses the link, but applications such as telnet and Netscape "do not work". Essentially, Transmission Control Protocol (TCP) packets are not making it across the link. Diagnostic:Set up a ptrace filter to check the ICMP echo return and set your debug value to
0x51. This will prove that the routing is correct and demonstrate that the issue is
not flow control. If it is a flow control issue you will see Cycle Redundancy
Check (CRC) errors with each packet. Command> set console Command> set debug 0x51: Check for CRC errors with the following command: Command> show sx [port] Solution/Action:Either enable or disable compression at each end of the link using the following commands: To enable compression on a user profile that has already been configured : Command> set user [username] compression on To disable compression on a user profile that has already been configured : Command> set user [username] compression off Additional Information:Some applications are not user friendly. VJ compression is a negotiated option
during the IP Control Protocol (IPCP) phase of link establishment.
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