| A | B |
|---|
| telnet works at the | Application Layer |
| ping works at the | Network Layer |
| trace works at the | Network Layer |
| Telnet, a virtual terminal protocol that | is part of the TCP/IP protocol suite |
| telnet | the most complete networking test mechanism available |
| five | the number of simultaneous incoming Telnet sessions allowed |
| connect or telnet | command to establish a Telnet connection |
| exit or logout | command to end a Telnet session |
| Ping echo protocols are used to | test whether protocol packets are being routed |
| The exclamation points (!) ping result | indicate each successful echo from the ping command |
| A period (.) ping result | indicates your router timed out waiting for a given packet echo from the ping target |
| ping | uses the ICMP (Internet Control Message Protocol) |
| The trace command is | the ideal tool for finding where data is being sent in your network |
| Trace tests | each step along the way as you travel through the network to the destination |
| Trace takes advantage of | the error messages generated by routers when a packet exceeds its Time To Live (TTL) value |
| trace it tells | which router in the path was the last one to be reached |
| When using trace, if one of these routers had been unreachable, | you would have seen three asterisks (*) instead of the name of the router |
| trace continues attempting to reach the next step until | you escaped using the Ctrl-Shift-6 escape sequence |
| show ip route | command to determine whether a routing table entry exists for the target network |
| show interfaces serial | command output is display of the line and data link protocol status. |
| serial 1 up | triggered by a Carrier Detect signal, and refers to the physical layer status |
| line protocol is up | triggered by keepalive frames, refers to the data link framing |
| show interfaces | display the statistics that reflect router operation since the last time the counters were cleared |
| clear counters | reset the counters to 0 so you get a better picture of the current status of the network |
| debug | used to check real time traffic on the network |
| show cdp neighbors | displays the neighbor's port type and number |
| CDP (Cisco Discovery Protocol) | protocol used to show summary configuration of directly connected Cisco routers |
