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Figure: Transit and peering relationships (Module 4)Consider AS X, which has customers, peers and providers. AS X exports routes according to its business relationships. AS X learns a route to prefix p from one of its customers.To which neighbors does AS X advertise this route?

Host A sends a file to host B over a TCP connection. Host B sends acknowledgments back to host A. Each acknowledgment carries a value called the receive window, rwnd.What does rwnd measure?

Consider a network of three nodes, x, y and z. The link costs are c(x,y) = 4, c(y,z) = 1 and c(x,z) = 50. The nodes run the distance vector algorithm. The algorithm has converged.The distance vectors settle in fewer iterations after the cost of link x-y drops to 1 than after it rises to 60.

Figure: A token bucket policer and a burst (Module 6)Consider a router that polices a flow with a token bucket. Tokens arrive at 1 token per second, and the bucket holds at most 50 tokens. Each packet needs one token.The flow has been idle, so the bucket is full. Then a burst of 80 packets arrives within 10 milliseconds, too fast for any new token to arrive.How does the policer handle the 80 packets?

A router performs the following five tasks.1. The router looks up the destination address of each packet in its forwarding table. 2. The router sends an ICMP error message to the source when the TTL of a packet has run out. 3. The switching fabric carries each packet from its input port to its output port. 4. The router runs OSPF to build its routing table. 5. The output port decides which queued packet goes out on the link next.Which three tasks add to the delay of every packet that crosses the router?

Figure: TCP cwnd over time (Module 2)The figure shows the congestion window, cwnd, of a TCP sender over time. A timeout occurs near the right edge of the plot.Which rule decides when TCP uses slow start and when it uses congestion avoidance?

The /home directory typically stores user files and folders.

A TCP sender can detect a loss in two ways: by receiving three duplicate ACKs, or by a retransmission timeout.How does the sender change its congestion window, cwnd, in each of these two cases?

The Linux kernel is the core component of the operating system.

Figure: Fixed-stride trie with a stride of 3 (Module 5)Consider a fixed-stride trie with a stride of 3. Each step of a search reads 3 bits of the address, so a search can stop only after 3, 6 or 9 bits, and so on. For this reason, every prefix stored in the trie must have a length of 3, 6, 9 and so on. The prefix database holds P3 = 11001*, which is 5 bits long. P3 ends in the middle of a step, so the trie cannot store it as it is.Which prefixes replace P3 in the trie?