- Posts: 1
- Thank you received: 0
Help on a networking qn.
18 years 8 months ago #12378
by junkpile
Help on a networking qn. was created by junkpile
Given a GEO synchronous 2Mb/s satellite link, with a total latency for the satellite link end to end is 280 milliseconds and assuming ideal conditions of no errors or congestion and negligible processing time.
1) Assume that the source has no windowing restrictions (infinite window size). In the satellite network, how much buffer space is needed to ensure that the sender is able to continuously send packets (assume 576 byte packets, 40 byte ACKs) until the first ACK is received?
Is this the correct answer: 2Mbits/s * 2 * 0.28s = 1.12Mbits = 140000bytes
1a)Is it possible to have this many unacknowledged bytes with TCP-reno?
No, because the maximum window size is only 64000bytes.
1b) Is this amount practical in a modern computer?
Not sure how to answer this part
2) Under what general conditions, if any, will a network be forced to stop sending and wait for an acknowledgment?
When the buffer space is full or the advertised recieve window is 0.
3) Under TCP-reno, what throughput (bits/sec received) is possible for the satellite network?
(64000bytes * 8bits) / 0.56s = 914285bits/s
A side question what is the usual buffer space in routers and such? Do they have the same kind of RAM used in normal computers (1GB and above)?
1) Assume that the source has no windowing restrictions (infinite window size). In the satellite network, how much buffer space is needed to ensure that the sender is able to continuously send packets (assume 576 byte packets, 40 byte ACKs) until the first ACK is received?
Is this the correct answer: 2Mbits/s * 2 * 0.28s = 1.12Mbits = 140000bytes
1a)Is it possible to have this many unacknowledged bytes with TCP-reno?
No, because the maximum window size is only 64000bytes.
1b) Is this amount practical in a modern computer?
Not sure how to answer this part
2) Under what general conditions, if any, will a network be forced to stop sending and wait for an acknowledgment?
When the buffer space is full or the advertised recieve window is 0.
3) Under TCP-reno, what throughput (bits/sec received) is possible for the satellite network?
(64000bytes * 8bits) / 0.56s = 914285bits/s
A side question what is the usual buffer space in routers and such? Do they have the same kind of RAM used in normal computers (1GB and above)?
Time to create page: 0.110 seconds