A Broadcast network

Soal :

2.5

A Broadcast network is one in wich a transmission from any one atteched station is received by all other attach station over a shared medium. Examples are a bus topologies, LAN, such as ethernet & a wireless radio network.

Discuss the need or lack of need for a network layer(OSI layer 3) in a broadcast network.

Jawaban :

Network Layer :

The Network Layer provides for the transfer of information between end system accross some sort of communication network. It relieves higher layers of the need to know anything about the underlying data transmission & switching

SOAL 

1. Imagine that you have trained your St. Bernard, Bernie, to carry

   a box of 100 data CD instead of a flask of Budweiser. These CDs

   each contain 700 MBs. The dog can travel at a rate of 18 km/hr.

   For what range of distances does Bernie have a higher data rate

   than a 45 Mbps T-3 (Transmission Level 3) line?

Ans: A CD can hold 700 MBs.

     100 CDs can have 700 * 100 = 70,000 MBs = 70,000 * 8 = 56,0000 Mbits

     Let's assume d be the distance in km.

     Time is expressed as d / speed = d / (18/3600) = 200d seconds

     So the data transfer rate for the dog is 56,0000 / 200d.

     We were asked to have 56,0000 / 200d > 45 Mbps

     200d < 56,0000 / 45

     d < 62.22 km

     For d < 62.22 km, the dog will have a higher data rate than a T3

     line.

Solutions to Chapter 1 Question 1.

The dog can carry 21 gigabytes, or 168 gigabits. A speed of 18 km/hour equals 0.005 km/sec. The time to travel distance x km is x /0.005 = 200x sec, yielding a data rate of 168/200x Gbps or 840/x Mbps. For x < 5.6 km, the dog has a higher rate than the communication line.

1.       A collection of five routers is to be connected in a point-to-point subnet.  Between each pair of routers, the designers may put a high-speed line, a medium speed line, a low-speed line, or no line.  If it takes 100 ms of computer time to generate and inspect each topology, how long will it take to inspect all of them ?

Jawaban :

Karena terdapat 5 router maka terdapat

 ₅C₂ = 10 kemungkinan pasangan router dalam point-to-point subnet.

Setiap pasangan mempunyai 4 buah kemungkinan pemasangan line (high-speed line, medium speed line, low-speed line, no line).

Maka jumlah topologinya = 4¹⁰ = 104.8576 buah

Karena tiap topologi membutuhkan 100ms untuk generate dan inspect topologi, maka waktu yg dibutuhkan untuk meng-inspect seluruh topologi = 100ms x  4¹⁰ = 104.857,6 s = ± 29 jam.