# 計算機網路計算題 packet transmission delay: L(bits) / R(Mbps) d(link length) / s(speed of light propagation delay) ![](https://hackmd.io/_uploads/HyqgsXEw3.png) 1*10^6(m) / 3*10^8(m/s) = 3.3*10^-2 ### What is the maximum number of connections that can be ongoing in the network at any one time? ![](https://hackmd.io/_uploads/rJvb3l8vn.png) 加起來 = 68 ### sends packets of data ![](https://hackmd.io/_uploads/BJRCng8D3.png) ### Packet delay: four sources ![](https://hackmd.io/_uploads/BkT-Te8D2.png) ![](https://hackmd.io/_uploads/H1LzTlIw3.png) ### Encapsulation: an end-end view ![](https://hackmd.io/_uploads/rynSaeIv3.png) ### ISO ![](https://hackmd.io/_uploads/rJk_axUP3.png) ![](https://hackmd.io/_uploads/BJaoagIDh.png) ### HTTP request message: general format ![](https://hackmd.io/_uploads/rJHkCgLvn.png) ### HTTP response status codes ![](https://hackmd.io/_uploads/S1I-RgUv2.png) ### DNS records ![](https://hackmd.io/_uploads/rJ2H0gUw3.png) ### Internet checksum ![](https://hackmd.io/_uploads/SJFeyZ8w2.png) ### Performance of rdt3.0 (stop-and-wait) ![](https://hackmd.io/_uploads/S15E1WIPn.png) ### rdt3.0: stop-and-wait operation ![](https://hackmd.io/_uploads/B1L8kZUD2.png) ### Pipelining: increased utilization ![](https://hackmd.io/_uploads/H1GF1bIPh.png) ### TCP round trip time, timeout ![](https://hackmd.io/_uploads/HJW01bUD3.png) ![](https://hackmd.io/_uploads/HyEJx-Iwn.png) ### TCP throughput ![](https://hackmd.io/_uploads/SJWVe-Uw2.png) ### IP Datagram format ![](https://hackmd.io/_uploads/HkEjxb8v3.png) ### dotted-decimal IP address notation: ![](https://hackmd.io/_uploads/SJLhx-Iw3.png) ### IP addressing: CIDR ![](https://hackmd.io/_uploads/SkPybbIvh.png) ### IPv6 datagram format ![](https://hackmd.io/_uploads/rkGfb-Iv3.png) ### Graph abstraction: link costs ![](https://hackmd.io/_uploads/ryYKbbUD3.png) ### Dijkstra’s algorithm ![](https://hackmd.io/_uploads/By8nZ-8Dh.png) ![](https://hackmd.io/_uploads/BJd6-bLD2.png) ### Cyclic Redundancy Check (CRC) ![](https://hackmd.io/_uploads/BJ4imbUDh.png) ### Channel partitioning MAC protocols: TDMA ![](https://hackmd.io/_uploads/HJ2r4ZLvn.png) ### CSMA/CD efficiency ![](https://hackmd.io/_uploads/r1YtE-UD2.png) ### MAC addresses ![](https://hackmd.io/_uploads/rkds4-UP3.png) ![](https://hackmd.io/_uploads/HythV-Lw3.png) ### aloha n = 2 p = 0.23 Np(1 - p)^2(N - 1) = 2 * 0.23 * (1 - 0.23)^2(2 - 1) = 0.27 or 27% efficiency. ### port number ![](https://hackmd.io/_uploads/HkitbtIvh.png)