Answers to the Chapter 6 "Do I Know This Already?" Quiz 745
71
Which requires more lines of source code, FTP or TFTP? Justify your answer.
TFTP requires less code. It was designed to be simple (that is, trivial), with the small
amount of memory needed to load the code ranking as an advantage to using TFTP. FTP
is much more robust, with many more features and more code.
72
Does FTP or TFTP perform error recovery? If so, describe the basics of how they perform
error recovery.
Both FTP and TFTP perform error recovery. FTP relies on TCP, whereas TFTP performs
application layer recovery one block of data at a time.
73
Describe the process used by IP routers to perform fragmentation and reassembly of
packets.
When a packet must be forwarded but the packet is larger than the maximum transmission
unit (MTU) size for the outgoing interface, the router fragments the packet, as long as the
Don't Fragment bit is not set. No IP router reassembles the fragments; fragments are
reassembled at the final destination host.
74
How many TCP segments are exchanged to establish a TCP connection? How many are
required to terminate a TCP connection?
A three-way connection establishment sequence is used, and a four-flow connection
termination sequence is used.
75
How many Class B-style networks are reserved by RFC 1918 private addressing?
Sixteen Class B networks are reserved for use as private networks in RFC 1918, networks
172.16.0.0 to 172.31.0.0.
Answers to the Chapter 6 "Do I Know This Already?" Quiz
1
Define what split horizon means to the contents of a routing update. Does this apply to
both the distance vector algorithm and the link-state algorithm?
Routing updates sent out an interface do not contain routing information about subnets
learned from updates entering the same interface. Split horizon is used only by distance
vector routing protocols.
2
Does IPX RIP use Split Horizon?
Split horizon means that routes learned by receiving updates on interface x will not be
advertised in the routing updates sent out interface x. IPX RIP uses split horizon by
default. SAP also uses split horizon concepts.
apA.fm Page 745 Monday, March 20, 2000 5:24 PM