Q1 Assignment 1 351

Question 1 Chapter 1: Review of packet-switching and circuit-switching networks Consider the network below, where a client is using his laptop to access the intranet web site. There are two main end-to-end communications involved: . a) when requesting the IP address of the web server from the DNS server; b) when accessing the web site. The standard server port numbers for DNS and HTTP are 53 and 80, respectively. The clients use random port numbers, which we consider in this case are 1220 for DNS and 1530 for HTTP IP: 1.1.1.1 MAC: AA-2F-2F-2F-2F-2F i1 S1 13 i2 DNS port: 1220 HTTP port: 1530 desktop DNS server IP: 3.3.3.3 MAC: CC-2F-2F-2F-2f-2F IP: 4.4.4.4 DNS port: 53 MAC: DD-2F-2F-2F-2F-2F R5 i2 R2 i1 i1IP: 51.51.51.51 i2 i1 MAC: 5A-2F-2F-2F-2F-2F i2 IP:52.52.52.52 i2 MAC: 5B-2F-2F-2f-2F-2F i 1 X i1 i1IP: 11.11.11.11 i1 MAC: 1A-2F-2F-2F-2F-2F i2 IP:12.12.12.12 i2 MAC: 18-2F-2F-2F-2f-2F i2 R1 i1IP: 21.21.21.21 i1 MAC: 2A-2F-2F-2F-2F-2F i2 IP:22.22.22.22 i2 MAC: 2B-2F-2F-2f-2F-2F R3 i1 X i1IP: 31.31.31.31 i1 MAC: 3A-2F-2F-2f-2F-2F i2 2 IP:32.32.32.32 i2 MAC: 3B-2F-2F-2F-2f-2F i2 S2 R4 web server i1 i1 11P: 41.41.41.41 i1 MAC: 4A-2F-2F-2F-2f-2F i2 IP:42.42.42.42 i2 MAC: 4B- i2 i2 IP: 2.2.2.2 MAC: BB-2F-2F-2F-2f-2F - HTTP port: 80 : Question 1: A. Which devices in the figure are part of the network core? List the devices in the alphabetical order, separated by a comma ? a B. Which devices in the figure runs applications? List the devices in the alphabetical order, separated by a comma C. Which layers (according to OSI model) are implemented in S1? List the layer from bottom to up, separated by a comma