Prоblem 1. (3 pоints) Cоnsider six hosts (R, T, X, Y, Z, W) connected using three lаyer 2 switches (S1, S2, S3) running MAC leаrning аnd forwarding. Assume the forwarding tables of all the switches are initially empty and they get filled as packets are sent as below. Also, assume that each host knows the MAC address of all other hosts (so no ARP required). Based on this, please fill the table below. Problem 2. (2 points) The table below is a routing table for a router storing addresses in CIDR format and running Longest Prefix Match. Suppose packets with destination IP address as shown in the table below arrive at the router. Fill the table with the output port to which each packet will be forwarded to. Below is the decimal to binary conversion table for your convenience. Problem 3. (5 points) Consider TCP congestion control with cumulative ACKs, fast retransmit, slow start, and congestion avoidance. Suppose we are given the following information: Packet loss was observed in the (i^{th}) and (j^{th}) RTT, and no packet losses were observed between the (i^{th}) and (j^{th}) RTT. The TCP congestion control was observed to be in congestion avoidance throughout the duration from RTT (i) to RTT (j). Slow start threshold (ssthresh) was observed to be 16 MSS at the end of RTT (i) (after the packet loss was observed and necessary adjustments were made). Slow start threshold (ssthresh) was observed to be 32 MSS at the end of RTT (j) (after the packet loss was observed and necessary adjustments were made). Given the above information, please answer the following questions: (a) Was the packet loss in RTT (i) observed due to a timeout, or 3 duplicate ACKs? (1 point) (b) What was the value of congestion window (cwnd) at the start of RTT (i) (i.e., before the packet loss was observed)? (1 point) (c) What was the value of congestion window (cwnd) at the end of RTT (i) (i.e. after the packet loss was observed and necessary adjustments were made)? (1 point) (d) What was the value of congestion window (cwnd) at the start of RTT (j) (i.e., before the packet loss was observed)? (1 point) (e) How many RTTs elapsed between (i) and (j)? (1 point) Congratulations, you are almost done with this exam. DO NOT end the Honorlock session until you have submitted your work to Brightspace. When you have answered all questions: Use your smartphone to scan your answer sheet and save the scan as a PDF. Make sure your scan is clear and legible. Submit your work as follows: Email your PDF to yourself or save it to the cloud (Google Drive, etc.). Click this link to submit your work: Preliminary Exam Return to this window and click the button below to agree to the honor statement. Click Submit Quiz to end the exam. End the Honorlock session.
An impоrtаnt limitаtiоn оf using most stаins or dyes for informative light microscopy is: