Ethernet Capture Effect

The teacher went over the following problem in class. However, I do not understand how he explains the work. He skips too many steps and jumps around. I have the final answer but I need a clear and complete explanation on how this problem is solved: Let A and B be two stations attempting to transmit on an Ethernet. Each has a steady queue of frames ready to send; A's frames will be numbered A1, A2, so on, and B's similarly. Let T = 51.2 microseconds be exponential backoff base unit. Suppose A and B simultaneously attempt to send frame 1, collide and happen to chose backoff times of 0xT and 1xT, respectively, meaning A wins the race and transmits A1 while B waits. At the end of this transm... click for more

Hops

A datagram subnet allows routers to drop packets whenever they need to. The probability of a router discarding a packet is p. Consider the case of a source host connected to a source router, which is connected to the destination router, and then to the destination host. If either of the routers discards a packet, the source host eventually times out and tries again. If both host-router and router-router lines are counted as hops, what is the mean number of a. Hops a packet makes per transmission? b. Transmissions a packet makes? c. Hops required per received packet?

Processing packets

A CPU in a router can process 2 million packets/sec. The load offered to it is 1.5 million packets/sec. If the route from source to destination contains 10 routers (having no additional traffic), how much time is spent being queued and serviced by the CPUs. Assume Poisson arrivals and departures at each router.

Subnet mask

A network on the Internet has a subnet mask of 255.255.240.0. What is the maximum number of hosts it can handle?

subnets

An organization has a class C network 200.1.1 and wants to form subnets for four departments, with hosts as follows: A 72 hosts B 35 hosts C 20 hosts D 18 hosts There are 145 hosts in all. a) Give a possible arrangement of subnet masks to make this possible. b) Suggest what the company might do if department D grows to 34 hosts.