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696 Chapter 9: Scenarios for Final Preparation
22
What layers in the OSI model do the ISDN specifications Q.920 and Q.930 most closely
match?
23
What ISDN reference points are supported by Cisco routers?
24
What command(s) can be used to discover details about a neighboring router without
logging in to that router?
Solutions to Scenario 9-3, Part C--Verification and Questions
The answers to the questions for Scenario 9-3, Part C are as follows:
1
The ping command uses the outgoing interface's IP address as the source address in the
packet, which in this case would be 170.1.12.3. Access lists 102 and 103 check the source
and destination IP addresses, looking for the subnets on the Ethernet segments. Therefore,
the packet is not matched. Look further in Example 9-21 to see an extended ping, with
source IP address 170.1.7.3 (R3's E0 IP address), and see that it fails. That's because the
extended ping calls for the use of 170.1.7.3 as the source IP address.
2
Two services are in the update instead of the three services listed in R2's SAP table. These
messages are displayed after the debug ipx sap activity command in Example 9-19. This
simply shows that the SAP filter on R2 is working properly.
3
The show ip route (Example 9-21) and show ipx route (Example 9-20) commands list
the IP and IPX addresses of the neighboring routers. Because only point-to-point
subinterfaces are in use, the show frame-relay map command (refer to Example 9-21)
does not show details of the neighboring routers' Layer 3 addresses. The show cdp
neighbor detail command (refer to Example 9-22) also shows information about IP and
IPX addresses.
4
The show ip route command (refer to Example 9-21) lists these numbers. The routes with
a C in the left column signify connected subnets.
5
The show ip route and show ipx route commands list the metric values (refer to
Examples 9-21 and 9-20, respectively). The metric value for each IP subnet is the second
of the two numbers inside brackets. Two IPX metrics are located between brackets for IPX
routes: the number of timer ticks and the number of hops.
6
The ping command can be used to verify IPX and IP connectivity, as well as several other
network layer (Layer 3) protocols (refer to Example 9-21).
7
Use the show access-lists command.
8
You can dial into a modem attached to the auxiliary port, or you can Telnet.
9
Press the up-arrow key, or press Ctrl+p to retrieve the last command. Then type the subnet
number, which leaves show ip route 168.11.12.64 on the command line. Press Enter.
ch09.fm Page 696 Monday, March 20, 2000 5:23 PM