1). What lessons do you draw from the repeated false starts of the CIBER team?

CIBER would have more server than one another, and more front, best test,

More to search information on CIBER.

 2). How could the process have been managed better?

If CIBER can hiring more employee to watch equipment and watch very close

Attention all job that they did, it will avoid all mistaken that they had before,

and more to prepare document, procedure for new employee so that they won't

make any mistake when they work on project.

3). Comment on the final configuration. Can you suggest radically different

configurations ? If so, compare with the actual.

They can go to token ring, but switched ethernet with a 100BASE-T backbone

might do the trick provided that the software. They uses 3 tiers between servers

and terminal ithernet fast responed time, and they also have back up servers like

ethernet explores, TCP/IP, etc.

1). Why would frequency or time-division multiplexing have been inefficient for the

Hawaiian application?

Because most communications between the campuses had one end at the central

computer. Using land lines to communicate among the islands was clearly not feasible,

dedicated point-to-point leased radio facilities were too expensive, and given the

bursty nature of the computer communications, sharing channels using frequency-

or time-division multiplexing was effiggivirny, especially considering that the

eventual plan was to support hundreds of terminals. 

2). Suppose that instead of a few remote stations, there were thousands. Would polling

be a feasible option?

For a small number of locations, the transmitter at Oahu could sequentially and continually ask

(poll) each station if it had something to send.

3). Suppose that instead of there being obstacles between the remote stations, so that the

remote stations could not communicate with one another, all the stations could hear

each other's communication. How would you improve the Aloha protocol?

(Hint: Review the discussion CSMA/CD in chapter 9).

The stations would may high probability the colliding stations waited different, usually random t

times, so that two colliding stations would not wait the same amount of time and collide again

upon retransmitting.  One could not assume that the remote stations could hear each other's

communication, so the success of communication could only be determined by Menehune.

 4). Shortly after Abramson invented the Aloha protocol, Larry Roberts of ARPA pointed

out that the chance of collision could be reduced if the system were synchronized in

time slots that were a little longer than the maximum packet transmission time. That

is, no transmission could start except at the beginning of a slot. Give a qualitative

explanation of why this might be so. This variation is called slotted Aloha and the

original scheme is called pure Aloha.

 Abramson and his colleagues then had the idea of using Oahu as a base station for radio

Broadcast communication to the other six campuses using two radio channels, that is, with a

separate channel into Oahu and another channel out.

5). The Aloha scheme is simple and elegant; unfortunately, it does not make good use of

the channel. In the idealized case of random packet transmission from an infinite

number of stations, the maximum utilization is about one-sixth of the total capacity of

the channel. (Larry Robert's scheme doubled the utilization, but it was still small.)

Can you think of a way to gain the flexibility of Aloha random access while still using

the channel efficiently? (If you can't review the section on channel access in this chapter.)

the channel  supported a data a rate of 9600bps in a bandwidth of 100kHz. The problem

of access to the channel had to be dealt with.

 CHAPTER 12

2). A TCP segment consisting of 1500 bits of data and 160 bits of header is sent to the IP

layer, which appends another 160 bits of header. This is then transmitted through two

networks, each of which uses a 24-bit packet header. The destination network has a

maximum packet size of 800 bits. How many bits, including headers, are delivered to

the network layer protocol at the destination?

3 packets are needed

776 + 24 = 800

776 + 24 = 800

268 + 24 = 292

1892 bits or 1820 + (3 * 24) = 1892 bits

1820 = 1500 + 160 + 160

data header header