ECE 2305: Introduction to Communications and NetworksD-term 2014Homework+Lab 2: Due at start of class on 01-Apr.Please complete all five homework problems, and the twenty lab problems.Homework Problems1. Stallings Problem 2.4 from the “Problems” section, not the “Review Questions”.2. Stallings Problem 2.7.3. The signalx(t) =12sin(t) (in volts) undergoes an attenuation of 6 dB. What is the peak-to-peak voltage of the attenuated signal?4. Suppose a communication system needs 11 dB SNR for reliable communication. Assume thatthe noise floor is -100 dBm, and that a fiber optic cable with an attenuation of 0.12 dB/kmis chosen to connect the transmitter and receiver. What is the required transmit power (inwatts) if there is 40 km of cable between the transmitter and receiver?5. Stallings Problem 4.3.1
Lab 2: Application Layer DNS[adapted from J. Kurose and K.W. Ross]Before starting this lab, please make sure you have read section 24.2 in the textbook.Asdescribed in the textbook, the Domain Name System (DNS) translates hostnames to IP addresses,fulfilling a critical role in the Internet infrastructure. In this lab, we’ll take a closer look at the clientside of DNS. Recall that the client’s role in the DNS is relatively simple — a client sends aqueryto its local DNS server, and receives aresponseback. As shown in Figure 24.6 in the textbook,much can go on behind the scenes, invisible to the DNS clients, as the hierarchical DNS serverscommunicate with each other to either recursively or iteratively resolve the client’s DNS query.From the DNS client’s standpoint, however, the protocol is quite simple — a query is formulatedto the local DNS server and a response is received from that server.What to hand in:There are twenty questions below which you will encounter as you completethe lab. For each question, please provide the answer as well as necessary screenshots and packetprintouts to support your answer.Part I:nslookup1In this lab, we’ll make extensive use of thenslookuptool, which is available in most Linux/Unix andMicrosoft platforms today. To runnslookupin Linux/Unix, you just type the nslookup commandon the command line. To run it in Windows, open the Command Prompt and runnslookuponthe command line.In its most basic operation,nslookuptool allows the host running the tool to query any specifiedDNS server for a DNS record. The queried DNS server can be a root DNS server, a top-level-domainDNS server, an authoritative DNS server, or an intermediate DNS server (see the textbook fordefinitions of these terms). To accomplish this task,nslookupsends a DNS query to the specifiedDNS server, receives a DNS reply from that same DNS server, and displays the result.
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IP address, Domain Name System, Nslookup, local DNS server