Take the afternoon off turn it in on Thursday

 

Answers to the questions:

 

Resubmissions must be handwritten

 

 

 

 

 

 

 

 

 

 

 

 

 

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1.      For this diagram as modified from the text, identify for each node tell what characteristics guide a host to forward data to that node. For instance, Ethernet is characterized by two addresses in the Enet header (identify them for a.). Getting to other nodes may simply depend on an additional bit of information in the Enet header (Etype). Identify it. Other nodes are located by additional headers. What are they? What additional data must be supplied in these additional headers. Use the diagrams on the web site page TCP/IP Headers. As an example I might describe access to a POP3 mail process as:

 

Enet (DMAC, SMAC, Etype = 0x800); IP (ver. = 0x04, length = 20/0x14, Protocol = 0x06 TCP, Src IP, Dest IP); TCP (Src port, Dest port = 110, Seq, Ack)

 

The headers required for this service are Enet, IP, TCP. For parameters that are dynamically assigned the name is sufficient, unless they will be assigned a standard dynamic value such as 0.0.0.0 or ff-ff-ff-ff-ff-ff. Note for instance, that Enet (a) will only have an Enet header. Remember also that ARP and RARP are nearly the same protocol so only ARP is included. You dont need to include the minor fields. Remember that the Enet fields and for the most part the IP fields will be repetitive. If you have a question about which field to use, please e-mail me. Do not do IGMP or RARP.

 

The j. node will be, for instance:

Enet (DMAC, SMAC, Etype = 0x806); IP (ver. = 0x04, length = 20/0x14, Protocol = 17/0x11 UDP). To reach UDP alone is an incomplete transaction so there could be no Src/Dest IP addresses or Src/Dest ports. Likewise, Enet, IP, and TCP alone have to be incomplete.

 

(Please excuse the graphics, I couldnt get the XML graphics to work right.)

 

2.      a. As a network administrator your company has assigned you 8 class C-equivalent subnetworks that include the following address: 172.18.10.5. What subnet mask will be required to select these 8 subnetworks from the 172,18.0.0 Class B network? Remember the technique of using the maximum value for a byte and subtracting the aggregation number to obtain the last octet of the subnetmask.

b.                  What is the network address that this subnetwork mask defines in the Class B network 172.18.0.0?

c.                   What is the broadcast address for this subnetwork?

 

  1. You work for an ISP in Novato that has 16 contiguous Class C subnets that it has leased from ICANN. It has contracted with PacBell to pass its traffic to PacBell in the most compact form possible. Its range of networks is 218.95.16.0 to 218.95.31.0. What network will it advertise?

 

  1. Using classful (Class A, Class B, Class C) network rules what is the network class of each of the following network addresses and what is the network to which it belongs?

 

a.                   109.145.15.38

b.                  131.109.33.18

c.                   12.209.254.18

d.                  195.209.254.48

e.                   192.192.208.201

f.                    191.192.129.13

g.                   225.239.245.22

 

  1. Can the following pairs of hosts communicate via TCP/IP without a router?

 

a.                   109.145.16.38 and 109.145.17.39 classful network masks

b.                  109.145.16.38/255.255.0.0 and 109.145.17.39/255.255.0.0

c.                   109.145.16.38/255.255.240.0 and 109.145.17.39/255.255.240.0

d.                  109.145.16.38/21 and 109.145.17.39/255.255.240.0

e.                   109.145.16.38/20 and 109.145.17.39/255.255.240.0

f.                    109.145.16.38/255.255.255.0 and 109.145.17.39/255.255.255.0

g.                   109.145.16.38/255.255.255.0 and 109.145.17.39/24

h.                   109.145.31.38/20 and 109.145.33.39/20