728 Appendix A: Answers to the "Do I Know This Already?" Quizzes and Q&A Sections
12
What causes the output from an IOS ping command to display "UUUUU"?
U is an indication that an unreachable message was received. The type of unreachable
message is not implied by the "U".
13
How many bytes comprise an IPX address?
Ten bytes. The network portion is 32 bits, and the node portion is 48 bits. The node part
conveniently is the same size as a LAN MAC address.
14
Give an example of an IPX network mask used when subnetting.
There is no such thing as subnetting with IPX. This is an example of a question meant to
shake your confidence on the exam. Thoughts like, "I never read about subnetting IPX!"
can destroy your concentration. Be prepared for unusual questions or answers like this on
the exam.
15
Create a configuration enabling IPX on each interface, with RIP and SAP enabled on each
as well, for a 2501 (two serial, one Ethernet) router. Use networks 100, 200, and 300 for
interfaces S0, S1, and E0, respectively. Choose any node values.
ipx routing 0200.1111.1111
interface serial 0
ipx network 100
interface serial 1
ipx network 200
interface ethernet 0
ipx network 300
The node part of the address was supplied in the ipx routing command so that the IPX
addresses are easily recognizable on the serial interfaces. This helps with troubleshooting
because it will be easier to remember the IPX addresses used when pinging.
16
What show command lists the IPX address(es) of interfaces in a Cisco router?
show ipx interface. The other show commands list only the IPX network numbers, not
the entire IPX addresses.
Answers to the Chapter 5 Q&A Section
1
What do TCP, UDP, IP, and ICMP stand for? Which protocol is considered to be Layer 3
equivalent when comparing TCP/IP to the OSI protocols?
Transmission Control Protocol, User Datagram Protocol, Internet Protocol, and Internet
Control Message Protocol. Both TCP and UDP are Layer 4 protocols. ICMP is considered
a Layer 3 protocol because it is used for control and management of IP. IP is the core part
of the network layer of TCP/IP.
apA.fm Page 728 Monday, March 20, 2000 5:24 PM