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authormo khan <mo@mokhan.ca>2025-09-30 18:16:58 -0600
committermo khan <mo@mokhan.ca>2025-09-30 18:16:58 -0600
commit8ea314dd772d6970470dfa79e2a76001ff0f2d9f (patch)
tree2eff13eb9ef63c4acfbdfa1b816f87e6261020c8 /assignments/3
parent52f421b5833efba917ca762fe5c8c2a66b907f83 (diff)
answer 2a
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@@ -232,14 +232,18 @@ Context:
- Distance: 180 m
- Frame: 1,024 bits
-- Propagation Speed: 2\*10^8 m/sec
+- Propagation Speed: 2 * 10^8 m/sec
- Backoff intervals: multiple of 512 bits
- Store and forward delay: 20-bit transmission time
> a) What is the one-way propagation delay (including all repeater delays) between A and B in seconds? At what time is A's packet completely delivered at B?
-> b) Now suppose that only A has a packet to send and that the repeaters are replaced with switches. Suppose that each switch has an 8-bit processing delay in addition to a store-and-forward delay. At what time, in seconds, is A's packet delivered at B?
+- time = distance / speed (distance: 180 m, speed: 10^8 m/sec)
+- Cable propagation: 180 m / (2 * 10^8 m/sec) = 0.0000009 seconds
+- Three repeaters: 3 × (20 bits / 10^9 bps) = 0.00000006 seconds
+- Total one-way delay: 0.00000096 seconds
+> b) Now suppose that only A has a packet to send and that the repeaters are replaced with switches. Suppose that each switch has an 8-bit processing delay in addition to a store-and-forward delay. At what time, in seconds, is A's packet delivered at B?
## 2.4 802.11 RTS/CTS Transmission (10%)