Calling all computer nerds - Networks Question

[kirrz 0]

I have to do an assignment for a networks class and I've been a bit slack about keeping up.. now I'm a little screwed. I'm stuck on these 2 questions.. maybe someone can help me out???? Thanks in advance!!!

1) You have two 802.5 Token Ring LANS connected by a bridge. A station on the left segment sends a frame to a station on the right segment The bridge participates as a station in both left and right segments.
a) Should the bridge, after forwarding a copy to the right segment, pretend that it has received the frame by setting the address-recognized and frame-copied bits and then send the frame to the next station in the left segment or should it ignore this issue? Explain.

b) If we connect two Ethernet LANS, do we face the same issue?

2) End systems A and B are on the same 10Mbps Ethernet segment, the propagation delay between them is 250 bit times. Suppose A begins transmitting a frame, and before it finishes, B begins transmitting a frame. Can A finish transmitting before it detects that B has transmitted? Why or why not?

[Slurp56 0]

Quote

I have to do an assignment for a networks class and I've been a bit slack about keeping up.. now I'm a little screwed. I'm stuck on these 2 questions.. maybe someone can help me out???? Thanks in advance!!!

1) You have two 802.5 Token Ring LANS connected by a bridge. A station on the left segment sends a frame to a station on the right segment The bridge participates as a station in both left and right segments.
a) Should the bridge, after forwarding a copy to the right segment, pretend that it has received the frame by setting the address-recognized and frame-copied bits and then send the frame to the next station in the left segment or should it ignore this issue? Explain.

b) If we connect two Ethernet LANS, do we face the same issue?

2) End systems A and B are on the same 10Mbps Ethernet segment, the propagation delay between them is 250 bit times. Suppose A begins transmitting a frame, and before it finishes, B begins transmitting a frame. Can A finish transmitting before it detects that B has transmitted? Why or why not?

I dont know for certain, but here is what I am thinking:

1.a) In a token ring network, yes, the bridge needs to set bits in the frame and send it on its way to keep the token passing on the left side. Otherwise no one would be able to transmit until a timeout and reset had occured. So yes, it needs to pass the token.

1.b) We do not face the same problem with ethernet. In a CSMA/CD network, other stations can continue to send and receive data when the line is available. If the frame drops, then the source computer times out and tries again when the line is clear. The Bridge wont retain control of the network.

2) I would say no, because an Ethernet frame minimum size is 64 bytes (512 bits).


Keep in mind its been a looooong time since I've studied this stuff.

________________________________________
I have proof-read this post 500 times, but I guarantee you'll still manage to find a flaw.

[MF42 0]

Uhhhh...
Twelve.
I think.

Matt