MarkdownNotes

View the Project on GitHub JungAn2/MarkdownNotes

1.1-1 WHAT IS THE INTERNET?

Which of the following descriptions below correspond to a "nuts-and-bolts" view of the Internet?

1.1-2 WHAT IS THE INTERNET (2)?

Which of the following descriptions below correspond to a "services" view of the Internet?

1.1-3 WHAT IS A PROTOCOL?

Which of the following human scenarios involve a protocol (recall: "Protocols define the format, order of messages sent and received among network entities, and actions taken on message transmission, receipt")?

1.2-1 ACCESS NETWORK PER-SUBSCRIBER SPEEDS.

Match the access network with the approximate speeds that a subscriber might experience. (Note: if you look these up, do so in the 8E textbook, slides,or video -- not in the 7E or earlier versions, since link access speeds are always increasing over the years).

1.2-2 LINK TRANSMISSION CHARACTERISTICS.

Which of the following physical layer technologies has the highest transmission rate and lowest bit error rate in practice?

1.3-1 ROUTING VERSUS FORWARDING.

Choose one the following two definitions that makes the correct distinction between routing versus forwarding.

1.3-2 PACKET SWITCHING VERSUS CIRCUIT SWITCHING (1).

Which of the characteristics below are associated with the technique of packet switching?

1.3-3 PACKET SWITCHING VERSUS CIRCUIT SWITCHING (2).

Which of the characteristics below are associated with the technique of circuit switching?

1.3-4 HOW MANY CALLS CAN BE CARRIED?

Consider the circuit-switched network shown in the figure below, with four circuit switches A, B, C, and D. Suppose there are 20 circuits between A and B, 19 circuits between B and C, 15 circuits between C and D, and 16 circuits between D and A.

What is the maximum number of connections that can be ongoing in the network at any one time?

[Note: you can find more questions like this one here.

    Just add them all up

1.3-5 TRYING OUT TRACEROUTE.

Perform a traceroute from your computer (on whatever network you happen to be on) to gaia.cs.umass.edu. Use traceroute (on Mac terminal) or tracert (on Windows command line) or tracepath (on a Linux command line). Enter the missing part of the name of the router just before the host gaia.cs.umass.edu is reached: ??.cs.umass.edu

Note: Routing may change, so the answer here may not be correct anymore. Also, if you are a Verizon user, there are known problems using traceroute with Verizon - if traceroute shows you two hops only to gaia.cs.umass.edu or any destination, skip this question.

1.3-6 WHAT IS A NETWORK OF NETWORKS?

When we say that the Internet is a “network of networks,” we mean? Check all that apply (hint: check two or more).

1.3-7 PACKET SWITCHING OR CIRCUIT-SWITCHING?

Consider a scenario in which 5 users are being multiplexed over a channel of 10 Mbps. Under the various scenarios below, match the scenario to whether circuit switching or packet switching is better.

1.4-1 COMPONENTS OF PACKET DELAY.

Match the description of each component of packet delay to its name in the pull down list.

1.4-2 COMPUTING PACKET TRANSMISSION DELAY(1).

Suppose a packet is L = 1500 bytes long (one byte = 8 bits), and link transmits at R = 1 Gbps (i.e., a link can transmit bits 1,000,000,000 bits per second). What is the transmission delay for this packet? [Note: you can find more problems like this one here.] 

    Equation = L/R
    L = 1500 * 8 bits
    R = 1,000,000,000 bps

1.4-3 COMPUTING PACKET TRANSMISSION DELAY (2).

Suppose a packet is L = 1200 bytes long (one byte = 8 bits), and link transmits at R = 100 Mbps (i.e., a link can transmit bits 100,000,000 bits per second). What is the transmission delay for this packet? [Note: you can find more problems like this one here.] 

    Equation = L/R
    L = 1200 * 8 bits
    R = 100,000,000 bps

1.4-4 COMPUTING PACKET TRANSMISSION DELAY (3).

Consider the network shown in the figure below, with three links, each with the specified transmission rate and link length. Assume the length of a packet is 8000 bits.

What is the transmission delay at link 2? [Note: you can find more problems like this one here.] 

    Transmition delay
    L/R
    L = 8000 bits
    R = 100 Mbps

1.4-5 COMPUTING PROPAGATION DELAY.

Consider the network shown in the figure below, with three links, each with the specified transmission rate and link length. Assume the length of a packet is 8000 bits. The speed of light propagation delay on each link is 3x10^8 m/sec

What is the propagation delay at (along) link 2? 

    Distance/Material delay
    (Make sure units match)
    Distance = 1000km
    Material = 3x10^8 m/sec

1.4-6 COMPUTING THROUGHPUT: A SIMPLE SCENARIO.

What is the maximum throughput achievable between sender and receiver in the scenario shown below?

Throughput is the bottleneck

1.4-7 COMPUTING THROUGHPUT.

Consider the scenario shown below, with four different servers connected to four different clients over four three-hop paths. The four pairs share a common middle hop with a transmission capacity of R = 300 Mbps. The four links from the servers to the shared link have a transmission capacity of RS = 50 Mbps. Each of the four links from the shared middle link to a client has a transmission capacity of RC = 90 Mbps.

What is the maximum achievable end-end throughput (an integer value, in Mbps) for each of four client-to-server pairs, assuming that the middle link is fairly shared (divides its transmission rate equally) and all servers are trying to send at their maximum rate? Your answer: [A] Mbps 

Throughput is the bottleneck
Also the question asked each of server/client not altogether

1.4-8 COMPUTING UTLILIZATION (1).

Consider the scenario shown below, with four different servers connected to four different clients over four three-hop paths. The four pairs share a common middle hop with a transmission capacity of R = 300 Mbps. The four links from the servers to the shared link have a transmission capacity of RS = 50 Mbps. Each of the four links from the shared middle link to a client has a transmission capacity of RC = 90 Mbps.

Assuming that the servers are all sending at their maximum rate possible, what are the link utilizations for the server links (with transmission capacity RS)? Enter your answer in a decimal form of 1.00 (if the utilization is 1) or 0.xx (if the utilization is less than 1, rounded to the closest xx).

Your answer: The utilization of the server links is: [A] 

Bottleneck/(client/server link)
bottleneck = 200
server link = 200

1.4-9 COMPUTING UTILIZATION (2).

Consider the scenario shown below, with four different servers connected to four different clients over four three-hop paths. The four pairs share a common middle hop with a transmission capacity of R = 300 Mbps. The four links from the servers to the shared link have a transmission capacity of RS = 50 Mbps. Each of the four links from the shared middle link to a client has a transmission capacity of RC = 90 Mbps.

Assuming that the servers are all sending at their maximum rate possible, what are the link utilizations of the shared link (with transmission capacity R)? Enter your answer in a decimal form of 1.00 (if the utilization is 1) or 0.xx (if the utilization is less than 1, rounded to the closest xx).

Your answer: The utilization of shared link is: [A] 

Bottleneck send max(50*4) / shared
Server send rate = 200Mbps
shared link = 300Mbps

1.4-10 COMPUTING UTILIZATION (3).

Consider the scenario shown below, with four different servers connected to four different clients over four three-hop paths. The four pairs share a common middle hop with a transmission capacity of R = 300 Mbps. The four links from the servers to the shared link have a transmission capacity of RS = 50 Mbps. Each of the four links from the shared middle link to a client has a transmission capacity of RC = 90 Mbps.

Assuming that the servers are all sending at their maximum rate possible, what are the link utilizations of the client links (with transmission capacity RC)? Enter your answer in a decimal form of 1.00 (if the utilization is 1) or 0.xx (if the utilization is less than 1, rounded to the closest xx).

Your answer: The utilization of client link is: [A] 

Bottleneck / client
bottleneck = 50
client = 90

1.5-1 LAYERS IN THE INTERNET PROTOCOL STACK.

Match the function of a layer in the Internet protocol stack to its its name in the pulldown menu.

1.5-2 WHAT’S A “PACKET” REALLY CALLED?

Match the name of an Internet layer with unit of data that is exchanged among protocol entities at that layer, using the pulldown menu.

1.5-3 PROTOCOL HEADERS.

Consider the figure below, showing a link-layer frame heading from a host to a router. There are three header fields shown. Match the name of a header with a header label shown in the figure.

1.5-4 WHAT IS "ENCAPSULATION"?

Which of the definitions below describe what is meant by the term "encapsulation"?

1.6-1 SECURITY DEFENSES.

Match the description of a security defense with its name.

1.7-1 NETWORKING HISTORY - WHEN DID IT HAPPEN?

Match the networking event with the time frame when the event occurred.

1.8-1 "WHO CONTROLS THE INTERNET?"

Match an organization name below with the role of the organization in Internet governance. To answer this question you’ll need to watch the Chapter 1 supplemental video on “Who Controls the Internet?”.

1.8-2 WHAT DOES IT MEAN TO "USE" THE INTERNET?

In 2021, the International Telecommunications Union (ITU) reported that 61.6% of the worlds’s population are “Internet users”. What does it mean to be an “Internet user” according to the ITU? To answer this question you’ll need to watch the chapter 1 supplemental video on “Who Uses the Internet?”

1.8-2 THE DIGITAL DIVIDE.

Between 2010 and 2018, which of the following digital divides has changed the least in the US? To answer this question you’ll need to watch the chapter 1 supplemental video on “Who Uses the Internet?” To answer this question you’ll need to watch the chapter 1 supplemental video on “Who Uses the Internet?”

2.1-1 THE CLIENT-SERVER PARADIGM.

Which of the characteristics below are associated with a client-server approach to structuring network applications (as opposed to a P2P approach)?

2.1-2 THE PEER-TO-PEER (P2P) PARADIGM.

Which of the characteristics below are associated with a P2P approach to structuring network applications (as opposed to a client-server approach)?

2.1-3 UDP SERVICE.

When an application uses a UDP socket, what transport services are provided to the application by UDP? Check all that apply.

2.1-4 TCP SERVICE.

When an application uses a TCP socket, what transport services are provided to the application by TCP? Check all that apply.

2.2-1 “HTTP IS STATELESS.”

What do we mean when we say “HTTP is stateless”? In answering this question, assume that cookies are not used. Check all answers that apply.

2.2-2 HTTP COOKIES.

What is an HTTP cookie used for?

2.2-3 THE HTTP GET.

What is the purpose of the HTTP GET message?

2.2-4 CONDITIONAL HTTP GET.

What is the purpose of the conditional HTTP GET request message?

2.2-5 A DETAILED LOOK AT AN HTTP GET (1).

Suppose a client is sending an HTTP GET request message to a web server, gaia.cs.umass.edu. Suppose the client-to-server HTTP GET message is the following:

GET /kurose_ross_sandbox/interactive/quotation2.htm 👉HTTP/1.1
Host: gaia.cs.umass.edu
Accept: text/plain, text/html, text/xml, image/jpeg, image/gif, audio/mpeg, audio/mp4, video/wmv, video/mp4,
Accept-Language: en-us, en-gb;q=0.1, en;q=0.7, fr, fr-ch, da, de, fi
If-Modified-Since: Wed, 09 Sep 2020 16:06:01 -0700
User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/535.11 (KHTML, like Gecko) Chrome/17.0.963.56 Safari/535.11

What version of HTTP is the client using? [Note: you can find additional questions similar to this here.]

2.2-6 A DETAILED LOOK AT AN HTTP GET (2).

Again, suppose a client is sending an HTTP GET request message to a web server, gaia.cs.umass.edu. The client-to-server HTTP GET message is the following (same as in previous problem):

GET /kurose_ross_sandbox/interactive/quotation2.htm HTTP/1.1
Host: gaia.cs.umass.edu
Accept: text/plain, text/html, text/xml, image/jpeg, image/gif, audio/mpeg, audio/mp4, video/wmv, video/mp4,
Accept-Language: 👉en-us, en-gb;q=0.1, en;q=0.7, fr, fr-ch, da, de, fi
If-Modified-Since: Wed, 09 Sep 2020 16:06:01 -0700
User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/535.11 (KHTML, like Gecko) Chrome/17.0.963.56 Safari/535.11

What is the language in which the client would least prefer to get a response? [You may have to search around the Web a bit to answer this.]

[Note: you can find additional questions similar to this here.]

Aprrently en-US does not equal US English

2.2-7 A DETAILED LOOK AT AN HTTP GET (3).

Again, suppose a client is sending an HTTP GET request message to a web server, gaia.cs.umass.edu. Suppose the client-to-server HTTP GET message is the following (same as in previous problem):

GET /kurose_ross_sandbox/interactive/quotation2.htm HTTP/1.1
Host: gaia.cs.umass.edu
Accept: text/plain, text/html, text/xml, image/jpeg, image/gif, audio/mpeg, audio/mp4, video/wmv, video/mp4,
Accept-Language: en-us, en-gb;q=0.1, en;q=0.7, fr, fr-ch, da, de, fi
👉If-Modified-Since: Wed, 09 Sep 2020 16:06:01 -0700
User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/535.11 (KHTML, like Gecko) Chrome/17.0.963.56 Safari/535.11

Does the client have a cached copy of the object being requested?

[Note: you can find additional questions similar to this here.]

2.2-8 A DETAILED LOOK AT AN HTTP REPLY.

Suppose now the server sends the following HTTP response message the client:

👉HTTP/1.0 200 OK
Date: Wed, 09 Sep 2020 23:46:21 +0000
Server: Apache/2.2.3 (CentOS)
Last-Modified: Wed, 09 Sep 2020 23:51:41 +0000
ETag:17dc6-a5c-bf716880.
Content-Length: 418
Connection: Close
Content-type: image/html

Will the web server close the TCP connection after sending this message? [Note: you can find more questions like this one here.]

2.2-9 WHY WEB CACHING?

Which of the following are advantages of using a web cache? Sselect one or more answers.

2.2-10 HTTP/2 VERSUS HTTP/1.1.

Which of the following are changes between HTTP 1.1 and HTTP/2? Note: select one or more answers.

2.2-11 WHAT'S IN AN HTTP REPLY?

Which of the following pieces of information will appear in a server’s application-level HTTP reply message? (Check all that apply.)

2.2-12 IF-MODIFIED-SINCE.

What is the purpose of the If-Modified-Since field in a HTTP GET request message

2.2-13 COOKIES.

What is the purpose of a cookie value in the HTTP GET request?

2.2-14 HTTP GET (EVEN MORE).

Suppose a client is sending an HTTP GET message to a web server, gaia.cs.umass.edu. Suppose the client-to-server HTTP GET message is the following:

GET /kurose_ross_sandbox/interactive/quotation2.htm HTTP/1.1
Host: gaia.cs.umass.edu
Accept: text/plain, text/html, text/xml, image/jpeg, image/gif, audio/mpeg, audio/mp4, video/wmv, video/mp4,
Accept-Language: en-us, en-gb;q=0.1, en;q=0.7, fr, fr-ch, da, de, fi
👉If-Modified-Since: Wed, 09 Sep 2020 16:06:01 -0700
User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/535.11 (KHTML, like Gecko) Chrome/17.0.963.56 Safari/535.11

Does the client have a cached copy of the object being requested?

2.2-15 WHAT HAPPENS AFTER AN HTTP REPLY?

Suppose an HTTP server sends the following HTTP response message a client:

👉HTTP/1.0 200 OK
Date: Wed, 09 Sep 2020 23:46:21 +0000
Server: Apache/2.2.3 (CentOS)
Last-Modified: Wed, 09 Sep 2020 23:51:41 +0000
ETag:17dc6-a5c-bf716880.
Content-Length: 418
Connection: Close
Content-type: image/html

Will the web server close the TCP connection after sending this message?

2.3-1 E-MAIL DELAYS.

How many RTTs are there from when a client first contacts an email server (by initiating a TCP session) to when the client can begin sending the email message itself – that is following all initial TCP or SMTP handshaking required? Recall the figure below from our class notes:

2.3-2 COMPARING AND CONTRASTING HTTP AND SMTP.

Which of the following characteristics apply to HTTP only (and do not apply to SMTP)? Note: check one or more of the characteristics below.

2.3-3 COMPARING AND CONTRASTING HTTP AND SMTP (2).

Which of the following characteristics apply to SMTP only (and do not apply to HTTP)? Note: check one or more of the characteristics below.

2.3-4 COMPARING AND CONTRASTING HTTP AND SMTP (3).

Which of the following characteristics apply to both HTTP and SMTP? Note: check one or more of the characteristics below.

2.3-5 WHICH E-MAIL PROTOCOL?

Match the functionality of a protocol with the name of a the email protocol (if any) that implements that functionality.

2.4-1 DNS FUNCTIONS

. Match the function of a server to a given type of DNS server in the DNS server hierarchy.

2.4-2 WHY DOES THE DNS PERFORM CACHING?

What is the value of caching in the local DNS name server? Check all that apply.

2.4-3 WHAT'S IN THE DNS TYPE A RESOURCE RECORD?

What information does the type “A” resource record hold in the DNS database? Check all that apply.

2.4-4 DNS IN ACTION (1).

Suppose that the local DNS server caches all information coming in from all root, TLD, and authoritative DNS servers for 20 time units. (Thus, for example, when a root server returns the name and address of a TLD server for .com, the cache remembers that this is the TLD server to use to resolve a .com name). Assume also that the local cache is initially empty, that iterative DNS queries are always used, that DNS requests are just for name-to-IP-address translation, that 1 time unit is needed for each server-to-server or host-to-server (one way) request/response, and that there is only one authoritative name server (each) for any .edu or .com domain.

Consider the following DNS requests, made by the local host at the given times:

t=0, the local host requests that the name gaia.cs.umass.edu be resolved to an IP address.
t=1, the local host requests that the name icann.org be resolved to an IP address.
t=5, the local host requests that the name cs.umd.edu be resolved to an IP address. (Hint: be careful!)
t=10, the local host again requests that the name gaia.cs.umass.edu be resolved to an IP address.
t=12, the local host requests that the name cs.mit.edu be resolved to an IP address.
t=30, the local host again requests that the name gaia.cs.umass.edu be resolved to an IP address. (Hint: be careful!)
Which of the requests require 8 time units to be resolved?

2.4-5 DNS IN ACTION (2).

Suppose that the local DNS server caches all information coming in from all root, TLD, and authoritative DNS servers for 20 time units. (Thus, for example, when a root server returns the name and address of a TLD server for .com, the cache remembers that this is the TLD server to use to resolve a .com name). Assume also that the local cache is initially empty, that iterative DNS queries are always used, that DNS requests are just for name-to-IP-address translation, that 1 time unit is needed for each server-to-server or host-to-server (one way) request/response, and that there is only one authoritative name server (each) for any .edu or .com domain.

Consider the following DNS requests, made by the local host at the given times:

t=0, the local host requests that the name gaia.cs.umass.edu be resolved to an IP address.
t=1, the local host requests that the name icann.org be resolved to an IP address.
t=5, the local host requests that the name cs.umd.edu be resolved to an IP address. (Hint: be careful!)
t=10, the local host again requests that the name gaia.cs.umass.edu be resolved to an IP address.
t=12, the local host requests that the name cs.mit.edu be resolved to an IP address.
t=30, the local host again requests that the name gaia.cs.umass.edu be resolved to an IP address. (Hint: be careful!)
Which of the requests require 6 time units to be resolved?

2.4-6 DNS IN ACTION (3).

Suppose that the local DNS server caches all information coming in from all root, TLD, and authoritative DNS servers for 20 time units. (Thus, for example, when a root server returns the name and address of a TLD server for .com, the cache remembers that this is the TLD server to use to resolve a .com name). Assume also that the local cache is initially empty, that iterative DNS queries are always used, that DNS requests are just for name-to-IP-address translation, that 1 time unit is needed for each server-to-server or host-to-server (one way) request/response, and that there is only one authoritative name server (each) for any .edu or .com domain.

Consider the following DNS requests, made by the local host at the given times:

t=0, the local host requests that the name gaia.cs.umass.edu be resolved to an IP address.
t=1, the local host requests that the name icann.org be resolved to an IP address.
t=5, the local host requests that the name cs.umd.edu be resolved to an IP address. (Hint: be careful!)
t=10, the local host again requests that the name gaia.cs.umass.edu be resolved to an IP address.
t=12, the local host requests that the name cs.mit.edu be resolved to an IP address.
t=30, the local host again requests that the name gaia.cs.umass.edu be resolved to an IP address. (Hint: be careful!)
Which of the requests require 2 time units to be resolved?

2.4-7 THE LOCAL DNS SERVER.

Check all of the phrases below that state a true property of a local DNS server.

2.4-8 THE DNS AUTHORITATIVE NAME SERVER.

What is the role of an authoritative name server in the DNS? (Check all that apply)

2.4-9 DNS AND HTTP CACHING.

We learned that in HTTP web browser caching, HTTP local web server caching, and in local DNS caching, that a user benefits (e.g., shorter delays over the case of no caching) from finding a local/nearby copy of a requested item. In which of the following forms of caching does a user benefit from its not only from its own recent requests (and cached replies) but also from recent requests made from other users?

2.6-1 CONTENT DISTRIBUTION NETWORKS (CDNS).

What approach is taken by a CDN to stream content to hundreds of thousands of simultaneous users?

2.6-2 STREAMING VIDEO DEFINITIONS

. Match the definition/function of an element or approach in a networked streaming video system, with its name.

2.6-3 WHAT IS DASH?

In DASH (Dynamic, Adaptive Streaming over HTTP), a server divides a video file into chunks that ... (pick best completion from below)

2.6-4 MANIFEST FILE.

Manifest file. What is the purpose of a manifest file in a streaming multimedia setting?

2.7-1 UDP SOCKETS.

Which of the following characteristics below are associated with a UDP socket? Check one or more that apply.

2.7-2 TCP SOCKETS.

Which of the following characteristics below are associated with a TCP socket? Check one or more that apply.

2.7-3 SERVER REPLY (UDP).

How does the networked application running on a server know the client IP address and the port number to reply to in response to a received datagram?

2.7-4 HOW MANY SOCKETS?

Suppose a Web server has five ongoing connections that use TCP receiver port 80, and assume there are no other TCP connections (open or being opened or closed) at that server. How many TCP sockets are in use at this server?

2.7-5 SOCKET CONNECT().

What happens when a socket connect() procedure is called/invoked?

3.1-1 LOCATION OF TRANSPORT-LAYER FUNCTIONALITY.

Where is transport-layer functionality primarily implemented?

3.1-2 TRANSPORT-LAYER FUNCTIONALITY.

True or False: The transport layer provides for host-to-host delivery service?

3.1-3 TRANSPORT LAYER SERVICES USING TCP.

Check all of the services below that are provided by the TCP protocol.

3.1-4 TRANSPORT-LAYER SERVICES USING UDP.

Check all of the services below that are provided by the UDP protocol.

3.1-5 NETWORK-LAYER FUNCTIONALITY.

The transport layer sits on top of the network layer, and provides its services using the services provided to it by the network layer. Thus it’s important that we know what is meant by the network layer’s “best effort” delivery service. True or False:

The network layer’s best-effort delivery service means that IP makes its “best effort” to deliver segments between communicating hosts, but it makes no guarantees. In particular, it does not guarantee segment delivery, it does not guarantee orderly delivery of segments, and it does not guarantee the integrity of the data in the segments.

3.2-1 TRANSPORT-LAYER DEMULTIPLEXING.

What is meant by transport-layer demultiplexing?

3.2-2 TRANSPORT-LAYER MULTIPLEXING.

What is meant by transport-layer multiplexing?

3.2-3 MULTIPLEXING/DEMULTIPLEXING: UDP PORT NUMBERS.

True or False: When multiple UDP clients send UDP segments to the same destination port number at a receiving host, those segments (from different senders) will always be directed to the same socket at the receiving host.

3.2-4 MULTIPLEXING/DEMULTIPLEXING: TCP PORT NUMBERS.

True or False: When multiple TCP clients send TCP segments to the same destination port number at a receiving host, those segments (from different senders) will always be directed to the same socket at the receiving host.

3.2-5 MULTIPLEXING UDP WITH IDENTICAL PORT NUMBERS.

True or False: It is possible for two UDP segments to be sent from the same socket with source port 5723 at a server to two different clients.

3.2-6 MULTIPLEXING TCP WITH IDENTICAL PORT NUMBERS.

True or False: It is possible for two TCP segments with source port 80 to be sent by the sending host to different clients.

3.3-1 DOES UDP PRESERVE APPLICATION-LAYER MESSAGE BOUNDARIES?

True or False: On the sending side, the UDP sender will take each application-layer chunk of data written into a UDP socket and send it in a distinct UDP datagram. And then on the receiving side, UDP will deliver a segment’s payload into the appropriate socket, preserving the application-defined message boundary.

3.3-2 UDP header fields.

Which of the fields below are in a UDP segment header? [Hint: note the use of the word "header" in this question statement.]

3.3-3 UDP SEGMENT LENGTH FIELD.

Why is the UDP header length field needed?

3.3-4 INTERNET CHECKSUM AND UDP.

Over what set of bytes is the checksum field in the UDP header computed over?

3.3-5 WHAT IS A CHECKSUM?

Which of the following statements are true about a checksum? Hint: more than one statement is true.

3.3-6 COMPUTING THE INTERNET CHECKSUM (1).

Compute the Internet checksum value for these two 16-bit words: 11110101 11010011 and 10110011 01000100 [Note: you can find more problems like this one here.]

Just add them up and flip

3.3-7 COMPUTING THE INTERNET CHECKSUM (2).

Compute the Internet checksum value for these two 16-bit words: 01000001 11000100 and 00100000 00101011 [Note: you can find more problems like this one here.]

3.3-8 UDP CHECKSUM: HOW GOOD IS IT?

True or False: When computing the Internet checksum for two numbers, a single flipped bit (i.e., in just one of the two numbers) will always result in a changed checksum.

3.3-9 UDP CHECKSUM: HOW GOOD IS IT?

True or False: When computing the Internet checksum for two numbers, a single flipped bit in each of the two numbers will always result in a changed checksum.

3.3-10 IP ADDRESSES AND PORT NUMBERS IN A UDP SEGMENT SENT IN REPLY.

Suppose a UDP segment (A in the figure below) arrives at a host with an IP address of 128.119.40.186. The source port in the UDP segment is 4829 and the destination port is 3546. The IP address of the sending host is 60.54.75.24.

Now consider the UDP datagram (and the IP datagram that will encapsulate it) sent in reply by the application on host 128.119.40.186 to the original sender host, labeled B in the figure above. Complete the sentences below ...

What are the source and destination port numbers and IP addresses? (Enter the integer port number or the 4-part dotted decimal IP address, included the period)

The source port number of the UDP segment (B) sent in reply is:

The source IP address of the IP datagram containing the UDP segment (B) sent in reply is:

The destination port number of the UDP segment (B) sent in reply is:

The destination IP address of the IP datagram containing the UDP segment (B) sent in reply is:

[Note: you can find more problems like this one here.]

3.4-1 RELIABLE DATA TRANSFER PROTOCOL MECHANISMS.

Consider the purposes/goals/use of different reliable data transfer protocol mechanisms. For the given purpose/goal/use match it to the RDT mechanism that is used to implement the given purpose/goal/use.

3.4-2 THE RDT 2.0 PROTOCOL.

Consider the rdt 2.0 sender and receiver shown below, with FSM transitions at the sender labeled S1, S2, and S3; and receiver transitions labeled R1 and R2.

Which of the following sequences of transitions could possibly occur as a result of an initial rdt_send() call at the sender, and possible later message corruption and subsequent error recovery.

3.4-3 THE RDT 2.1 PROTOCOL (A).

Consider the rdt2.1 sender and receiver FSMs shown below, with labeled transitions S1 through S6 at the sender, and transitions R1 through R6 at the receiver. The sender and receiver start in the “Wait for call 0 from above” and “Wait for 0 from below” states, respectively.

Suppose that no channel errors occur. A sequence of interleaved sender and receiver transitions is given below. Transitions S1 and S4 are already provided. Choose the sender or receiver transition for the unlabeled transitions x1, x2, x3, and x4 below to indicate the time-ordered sequence of transitions (interleaved sender and receiver transitions) that will result in two messages being delivered at the receiver, with the sender and receiver returning to their initial states (again, given that no channel errors occur).

S1, x1, x2, S4, x3, x4

3.4-4 THE RDT 2.1 PROTOCOL (B).

Consider the rdt2.1 sender and receiver FSMs shown below, with labeled transitions S1 through S6 at the sender, and transitions R1 through R6 at the receiver. The sender and receiver start in the “Wait for call 0 from above” and “Wait for 0 from below” states, respectively.

Suppose that the initial message transmission by the sender is corrupted, but that no other message transmissions are corrupted. Match the unlabeled transitions x1, x2, x3, x4, x5 in the time-ordered sequence of transitions below (interleaved sender and receiver transitions) that will occur following the initial S1 transition (which is corrupted), that will result in two messages being delivered at the receiver, with the sender and receiver returning to their initial states (again, given that the initial message transmission by the sender is corrupted). Note that transitions S1, S4, and S6 are already provided below.

S1 (message corrupted), x1, x2, x3, x4, S4, x5, S6.

3.4-5 THE RDT 2.1 PROTOCOL (C).

Consider the rdt2.1 sender and receiver FSMs shown below, with labeled transitions S1 through S6 at the sender, and transitions R1 through R6 at the receiver. The sender and receiver start in the “Wait for call 0 from above” and “Wait for 0 from below” states, respectively.

Suppose that the first packet from the sender is correctly received at the receiver but that ACK message sent from receiver-to-sender is corrupted; all other messages (before or after that ACK) are transmitted error-free. Match the unlabeled transitions x1, x2, x3, x4, x5 in the time-ordered sequence of transitions below (interleaved sender and receiver transitions) that will occur following the initial S1 transition, which is followed by a corrupted ACK transmission, that will result in a message being delivered at the receiver, with the sender and receiver returning to their initial states. Note that some transitions are already provided below.

S1, x1 (ACK corrupted), x2, x3, x4, S4, x5, S6.

3.4-6 CUMULATIVE ACK.

What is meant by a cumulative acknowledgment, ACK(n)?

3.4-7 STOP-AND-WAIT: CHANNEL UTILIZATION.

Suppose a packet is 10K bits long, the channel transmission rate connecting a sender and receiver is 10 Mbps, and the round-trip propagation delay is 10 ms. What is the maximum channel utilization of a stop-and-wait protocol for this channel?

3.4-8 CHANNEL UTILIZATION WITH PIPELINING.

Suppose a packet is 10K bits long, the channel transmission rate connecting a sender and receiver is 10 Mbps, and the round-trip propagation delay is 10 ms. What is the channel utilization of a pipelined protocol with an arbitrarily high level of pipelining for this channel?

3.4-9 CHANNEL UTILIZATION WITH PIPELINING (MORE).

Suppose a packet is 10K bits long, the channel transmission rate connecting a sender and receiver is 10 Mbps, and the round-trip propagation delay is 10 ms. How many packets can the sender transmit before it starts receiving acknowledgments back?

3.4-10 PIPELINING.

Which of the following statements about pipelining are true? One or more statements may be true.

3.4-11 PACKET BUFFERING IN GO-BACK-N.

What are some reasons for discarding received-but- out-of-sequence packets at the receiver in GBN? Indicate one or more of the following statements that are correct.

3.4-12 PACKET BUFFERING IN GO-BACK-N (MORE).

What are some reasons for not discarding received-but- out-of-sequence packets at the receiver in GBN? Indicate one or more of the following statements that are correct.

3.4-13 RECEIVER OPERATION IN SELECTIVE REPEAT.

In the SR receiver window (see diagram below, taken from PPT slides and video), why haven’t the red packets been delivered yet? Check the one or more reasons below that apply.

3.4-14 RECEIVER OPERATION IN SELECTIVE REPEAT (MORE).

In SR, why does the receiver have to acknowledge packets with sequence numbers that are less than (and to the left of) those in its window, which starts at rcv_base.

3.5-1 TCP RELIABILITY SEMANTICS.

True or False: On the sending side, the TCP sender will take each application-layer chunk of data written into a TCP socket and send it in a distinct TCP segment. And then on the receiving side, TCP will deliver a segment’s payload into the appropriate socket, preserving the application-defined message boundary.

3.5-2 TCP SEGMENT FORMAT.

For the given function of a field in the TCP segment, select the name of that field from the pull-down list.

3.5-3 TCP SEQUENCE NUMBERS AND ACKS (1).

Consider the TCP Telnet scenario below (from Fig. 3.31 in text). Why is it that the receiver sends an ACK that is one larger than the sequence number in the received datagram?

3.5-4 TCP SEQUENCE NUMBERS AND ACKS (2).

Suppose that as shown in the figure below, a TCP sender is sending segments with 100 bytes of payload. The TCP sender sends five segments with sequence numbers 100, 200, 300, 400, and 500. Suppose that the segment with sequence number 300 is lost. The TCP receiver will buffer correctly-received but not-yet-in-order segments for later delivery to the application layer (once missing segments are later received).

Complete the sentences below ....

3.5-5 TCP RTT ESTIMATION: EWMA.

Consider TCP use of an exponentially weighted moving average (EWMA) to compute the nth value of the estimated RTT:

EstimatedRTTn = (1- a)EstimatedRTTn-1 + aSampleRTTn

True or False: with this EWMA algorithm the value of EstimatedRTTn has no dependence on the earlier sample, SampleRTTn-1

3.5-6 TCP TIMER MANAGEMENT.

Consider the TCP Telnet scenario below (from Fig. 3.36 in text). What timer-related action does the sender take on the receipt of ACK 120?

3.5-7 TCP FLOW CONTROL.

True or False: with TCP’s flow control mechanism, where the receiver tells the sender how much free buffer space it has (and the sender always limits the amount of outstanding, unACKed, in-flight data to less than this amount), it is not possible for the sender to send more data than the receiver has room to buffer.

3.5-8 TCP CONNECTION MANAGEMENT.

Match the description of a TCP connection management message with the name of the message used to accomplish that function.

3.5-9 TCP FAST RETRANSMIT.

Consider TCP’s Fast Retransmit optimization (see Figure 3.37 from the text, below). Of course, the sender doesn't know for sure that the segment with sequence # 100 is actually lost (it can’t see into the channel). Can a sender get three duplicate ACKs for a segment that in fact has not been lost? Which of the following statements are true? Suppose a channel can lose, but will not corrupt, messages.

    Both of them is the answer

3.6-1 CONGESTION CONTROL VERSUS FLOW CONTROL.

Consider the five images below. Indicate which of these images suggest the need for flow control (the others would suggest the need for congestion control).

3.6-2 TWO CONGESTED SENDERS.

Consider the figure below, which shows the application-to-application throughput achieved when two senders are competing at a shared bottleneck link. Suppose that when the overall arrival rate, lambdain' (for each sender) is close to R/2, the throughput to the application layer (at each receiver), lambdaout, is equal to 0.8 * lambdain'.

What fraction of the packets transmitted at the sender are retransmissions?

3.6-3 NETWORK-ASSISTED OR END-END CONGESTION CONTROL?

Which of the following actions are used in network-assisted congestion control (say versus end-end congestion control) to signal congestion. Check all that apply.

3.6-4 NETWORK-ASSISTED OR END-END CONGESTION CONTROL (2)?

Which of the following actions are associated with end-end congestion control (say versus network-assisted congestion control). Check all that apply.

3.6-5 DIFFERENT APPROACHES TOWARDS CONGESTION CONTROL.

Use the pulldown menu to match a congestion control approach to how the sender detects congestion.

3.7-1 TCP’S AIMD ALGORITHM.

Which of the following statements about TCP’s Additive-increase-multiplicative-decrease (AIMD) algorithm are true? Check all that are true.

3.7-2 TCP’S AIMD ALGORITHM (2).

How is the sending rate typically regulated in a TCP implementation?

3.7-3 TCP’S SLOWSTART ALGORITHM.

Which of the following best completes this sentence: "In the absence of loss, TCP slow start increases the sending rate ... "

3.7-4 UNCONTROLLED TRANSPORT-LAYER SENDERS.

Consider the transport-layer flows interacting at a congested link. In the face of such congestion, what happens at this link to a transport-layer flow that does not cut back on its sending rate?

3.7-5 TCP CUBIC.

Assuming that the congestion window size,cwnd, has not yet reached Wmax, TCP CUBIC will ... (check all that apply)

3.7-6 DELAY-BASED CONGESTION CONTROL.

For delay-based congestion control, match the sender action to the relationship of the currently measured throughput to the value of cwnd/RTTmin

3.8-1 QUIC STREAMS.

What are advantages of the streams concept in QUIC? Select all that apply.

3.8-2 QUIC: AN APPLICATION-LAYER PROTOCOL.

What are advantages of implementing transport-layer functionality in QUIC at the application layer? Select all that apply.

4.1-1 THE NETWORK LAYER - WHERE IS IT?

Check all of the statements below about where (in the network) the network layer is implemented that are true.

4.1-2 FORWARDING VERSUS ROUTING.

Consider the travel analogy discussed in the textbook - some actions we take on a trip correspond to forwarding and other actions we take on a trip correspond to routing. Which of the following travel actions below correspond to forwarding? The other travel actions that you don't select below then correspond to routing.

4.1-3 THE CONTROL PLANE VERSUS THE DATA PLANE.

For each of the actions below, select those actions below that are primarily in the network-layer data plane. The other actions that you don't select below then correspond to control-plane actions.

4.1-4 WHAT TYPE OF CONTROL PLANE?

We've seen that there are two approaches towards implementing the network control plane - a per-router control-plane approach and a software-defined networking (SDN) control-plane approach. Which of the following actions occur in a per-router control-plane approach? The other actions that you don't select below then correspond to actions in an SDN control plane.

4.1-5 BEST EFFORT SERVICE.

Which of the following quality-of-service guarantees are part of the Internet’s best-effort service model? Check all that apply.

4.2-1 WHAT'S INSIDE A ROUTER?

Match the names of the principal router components (A,B,C,D below) with their function and whether they are in the network-layer data plane or control plane.

4.2.1

4.2-2 WHERE DOES DESTINATION ADDRESS LOOKUP HAPPEN?

Where in a router is the destination IP address looked up in a forwarding table to determine the appropriate output port to which the datagram should be directed?

4.2-3 WHERE DOES "MATCH+ACTION" HAPPEN?

Where in a router does "match plus action" happen to determine the appropriate output port to which the arriving datagram should be directed?

4.2-4 LONGEST PREFIX MATCHING.

Consider the following forwarding table below. Indicate the output to link interface to which a datagram with the destination addresses below will be forwarded under longest prefix matching. (Note: The list of addresses is ordered below. If two addresses map to the same output link interface, map the first of these two addresses to the first instance of that link interface.) [Note: You can find more examples of problems similar to this here.]

4.2.4

Note:
    Since this is in order, just set which ever come first at the top to be first destination.

4.2-5 PACKET DROPPING.

Suppose a datagram is switched through the switching fabric and arrives to its appropriate output to find that there are no free buffers. In this case:

4.2-6 HOL BLOCKING.

What is meant by Head of the Line (HOL) blocking?

4.2-7 PACKET SCHEDULING (SCENARIO 1, FCFS).

Consider the pattern of red and green packet arrivals to a router’s output port queue, shown below. Suppose each packet takes one time slot to be transmitted, and can only begin transmission at the beginning of a time slot after its arrival. Indicate the sequence of departing packet numbers (at t = 1, 2, 3, 4, 5, 7, 8) under FCFS scheduling. Give your answer as 7 ordered digits (each corresponding to the packet number of a departing packet), with a single space between each digit, and no spaces before the first or after the last digit, e.g., in a form like 7 6 5 4 3 2 1). [Note: You can find more examples of problems similar to this here.]

4.2.7

Note:
    First come first serve

4.2-8 PACKET SCHEDULING (SCENARIO 1, PRIORITY).

Consider the pattern of red and green packet arrivals to a router’s output port queue, shown below. Suppose each packet takes one time slot to be transmitted, and can only begin transmission at the beginning of a time slot after its arrival. Indicate the sequence of departing packet numbers (at t = 1, 2, 3, 4, 5, 7, 8) under priority scheduling, where red packets have higher priority. Give your answer as 7 ordered digits (each corresponding to the packet number of a departing packet), with a single space between each digit, and no spaces before the first or after the last digit, e.g., in a form like 7 6 5 4 3 2 1).

4.2.7

Note:
    Red has more priority than green

4.2-9 PACKET SCHEDULING (SCENARIO 1, RR).

Consider the pattern of red and green packet arrivals to a router’s output port queue, shown below. Suppose each packet takes one time slot to be transmitted, and can only begin transmission at the beginning of a time slot after its arrival. Indicate the sequence of departing packet numbers (at t = 1, 2, 3, 4, 5, 7, 8) under round robin scheduling, where red starts a round if there are both red and green packets ready to transmit after an empty slot. Give your answer as 7 ordered digits (each corresponding to the packet number of a departing packet), with a single space between each digit, and no spaces before the first or after the last digit, e.g., in a form like 7 6 5 4 3 2 1).

4.2.7

Note:
    Alternate between red and green

4.2-10 PACKET SCHEDULING (SCENARIO 2, FCFS).

Consider the pattern of red and green packet arrivals to a router’s output port queue, shown below. Suppose each packet takes one time slot to be transmitted, and can only begin transmission at the beginning of a time slot after its arrival. Indicate the sequence of departing packet numbers (at t = 1, 2, 3, 4, 5, 7, 8) under FCFS scheduling. Give your answer as 7 ordered digits (each corresponding to the packet number of a departing packet), with a single space between each digit, and no spaces before the first or after the last digit, e.g., in a form like 7 6 5 4 3 2 1).

4.2.10

4.2-11 PACKET SCHEDULING (SCENARIO 2, PRIORITY).

Consider the pattern of red and green packet arrivals to a router’s output port queue, shown below. Suppose each packet takes one time slot to be transmitted, and can only begin transmission at the beginning of a time slot after its arrival. Indicate the sequence of departing packet numbers (at t = 1, 2, 3, 4, 5, 7, 8) under priority scheduling, where red packets have higher priority. Give your answer as 7 ordered digits (each corresponding to the packet number of a departing packet), with a single space between each digit, and no spaces before the first or after the last digit, e.g., in a form like 7 6 5 4 3 2 1).

4.2.10

4.2-12 PACKET SCHEDULING (SCENARIO 2, RR).

Consider the pattern of red and green packet arrivals to a router’s output port queue, shown below. Suppose each packet takes one time slot to be transmitted, and can only begin transmission at the beginning of a time slot after its arrival. Indicate the sequence of departing packet numbers (at t = 1, 2, 3, 4, 5, 7, 8) under round robin scheduling, where red starts a round if there are both red and green packets ready to transmit after an empty slot. Give your answer as 7 ordered digits (each corresponding to the packet number of a departing packet), with a single space between each digit, and no spaces before the first or after the last digit, e.g., in a form like 7 6 5 4 3 2 1).

4.2.10

4.3-1 WHAT IS THE INTERNET PROTOCOL?

What are the principal components of the IPv4 protocol (check all that apply)?

4.3-2 THE IPV4 HEADER.

Match each of the following fields in the IP header with its description, function or use.

4.3-3 WHAT IS AN IP ADDRESS ACTUALLY ASSOCIATED WITH?

Which of the following statements is true regarding an IP address? (Zero, one or more of the following statements is true).

4.3-4 WHAT IS A SUBNET?

What is meant by an IP subnet? (Check zero, one or more of the following characteristics of an IP subnet).

4.3-5 SUBNETTING(A).

Consider the three subnets in the diagram below.

4.3.5

What is the maximum # of interfaces in the 223.1.2/24 network?

4.3-6 SUBNETTING(B).

Consider the three subnets in the diagram below.

4.3.5

What is the maximum # of interfaces in the 223.1.3/29 network?

4.3-7 SUBNETTING(C).

Consider the three subnets in the diagram below.

4.3.5

Which of the following addresses can not be used by an interface in the 223.1.3/29 network? Check all that apply.

4.3-8 PLUG-AND-PLAY.

What is meant by saying that DHCP is a "plug and play" protocol?

4.3-9 DHCP REQUEST MESSAGE.

Which of the following statements about a DHCP request message are true (check all that are true). Hint: check out Figure 4.24 in the 7th and 8th edition of our textbook.

4.3-10 IPV4 VERSUS IPV6.

Which of the following fields occur ONLY in the IPv6 datagram header (i.e., appear in the IPv6 header but not in the IPv4 header)? Check all that apply.

4.3-11 PURPOSE OF DHCP.

What is the purpose of the Dynamic Host Configuration Protocol?

4.4-1 DESTINATION-BASED MATCH+ACTION.

Destination-based forwarding, which we studied in section 4.2, is a specific instance of match+action and generalized forwarding. Select the phrase below which best completes the following sentence: "In destination-based forwarding, ..."

4.4-2 GENERALIZED MATCH+ACTION.

Which of the following match+actions can be taken in the generalized OpenFlow 1.0 match+action paradigm that we studied in Section 4.4? Check all that apply.

4.4-3 WHAT FIELDS CAN BE MATCHED IN GENERALIZED MATCH+ACTION.

Which of the following fields in the frame/datagram/segment/application-layer message can be matched in OpenFlow 1.0? Check all that apply.

4.4-4 MATCH+ACTION IN OPENFLOW 1.0.

Consider the figure below that shows the generalized forwarding table in a router. Recall that a * represents a wildcard value. Now consider an arriving datagram with the IP source and destination address fields indicated below. For each source/destination IP address pair, indicate which rule is matched. Note: assume that a rule that is earlier in the table takes priority over a rule that is later in the table and that a datagram that matches none of the table entries is dropped.

4.4.4.jpg

4.4-5 CRAFTING NETWORK-WIDE FORWARDING USING FLOW TABLES.

Consider the network below. We want to specify the match+action rules at s3 so that only the following network-wide behavior is allowed:

  1. traffic from 128.119/16 and destined to 137.220/16 is forwarded on the direct link from s3 to s1;
  2. traffic from 128.119/16 and destined to 67.56/16 is forwarded on the direct link from s3 to s2;
  3. incoming traffic via port 2 or 3, and destined to 128.119/16 is forwarded to 128.119/16 via local port 1.
  4. No other forwarding should be allowed. In particular s3 should not forward traffic arriving from 137.220/16 and destined for 67.56/16 and vice versa. From the list of match+action rules below, select the rules to include in s3's flow table to implement this forwarding behavior. Assume that if a packet arrives and finds no ddmatch rule, it is dropped.

4.4.5.jpg

4.4-6 CRAFTING NETWORK-WIDE FORWARDING USING FLOW TABLES (MORE).

Consider the network below. We want to specify the match+action rules at s3 so that s3 acts only as a relay for traffic between 137.220/16 and 67.56/16. In particular s3 should not accept/forward and traffic to/from 128.119/16. From the list of match+action rules below, select the rules to include in s3's flow table to implement this forwarding behavior. Assume that if a packet arrives and finds no ddmatch rule, it is dropped.

4.4.5.jpg

4.4-7 GENERALIZED FORWARDING.

What is meant by generalized forwarding (as opposed to destination-based forwarding) in a router or switch?

4.5-1 WHAT'S A "MIDDLEBOX"?

Which of the following network devices can be thought of as a "middlebox"? Check all that apply.

4.5-2 THE "THIN WAIST" OF THE INTERNET.

What protocol (or protocols) constitutes the "thin waist" of the Internet protocol stack? Check all that apply.

4.5-3 THE END-TO-END PRINCIPLE.

Which of the statements below are true statements regarding the "end-to-end principle"? Check all that apply.

4.5-4 THE INTERNET HOURGLASS.

What is meant when it is said that the Internet has an “hourglass” architecture? See the picture below if you are unfamiliar with an "hourglass".

4.5.4

4.5-5 FEDERAL REGULATION AND THE INTERNET.

In the US, which of the following services has been regulated by the Federal Communications Commission (FCC) going back into the 20th century?

5.1-1 ROUTING VERSUS FORWARDING.

Which of the following statements correctly identify the differences between routing and forwarding. Select one or more statements.

5.1-2 APPROACHES TOWARDS IMPLEMENTING THE CONTROL PLANE.

Match the name of the approach towards implementing a control plane with a description of how this approach works.

5.2-1 WHAT’S A “GOOD” PATH?

What is the definition of a “good” path for a routing protocol? Chose the best single answer.

5.2-2 DIJKSTRA’S LINK-STATE ROUTING ALGORITHM.

Consider Dijkstra’s link-state routing algorithm that is computing a least-cost path from node a to other nodes b, c, d, e, f. Which of the following statements is true. (Refer to Section 5.2 in the text for notation.)

5.2-3 WHAT TYPE OF ROUTING?

Match the name of a general approach to routing with characteristics of that approach.

5.2-4 DIJKSTRA’S LINK-STATE ROUTING ALGORITHM (PART 1).

Consider the graph shown below and the use of Dijkstra’s algorithm to compute a least cost path from a to all destinations. Suppose that nodes b and d have already been added to N’. What is the next node to be added to N' (refer to the text for an explanation of notation).

5.2.4

5.2-5 DIJKSTRA’S LINK-STATE ROUTING ALGORITHM (PART 2).

Consider the graph shown below and the use of Dijkstra’s algorithm to compute a least cost path from a to all destinations. Suppose that nodes b and d have already been added to N’. What is the path cost to the next node to be added to N' (refer to the text for an explanation of notation).

5.2.4

5.3-1 ROUTING WITHIN OR AMONG NETWORKS.

Match the terms "interdomain routing" and intradomain routing" with their definitions. Recall that in Internet parlance, an “AS” refers to “Autonomous System” – a network under the control of a single organization.

5.3-2 OPEN SHORTEST PATH FIRST (OSPF).

Check the one or more of the following statements about the OSPF protocol that are true.

5.3-3 OPEN SHORTEST PATH FIRST (OSPF).

Consider the OSPF routing protocol. Which of the following characteristics are associated with OSPF (as opposed to BGP)?

5.4-1 ROUTING WITHIN NETWORKS?

Among the following protocols, terminology or considerations, indicate those that are associated with "routing within a single network (typically owned and operated by one organization)."

5.4-2 PATH ADVERTISEMENT AND POLICY (PART 1).

Suppose a provider network only wants to carry traffic to/from its customer networks (i.e., to provide no transit service), and customer networks only want to carry traffic to/from itself. Consider the figure below. To implement this policy, to which of the following networks would network C advertise the path Cy?

5.4.2

5.4-3 PATH ADVERTISEMENT AND POLICY (PART 2).

Again, suppose a provider network only wants to carry traffic to/from its customer networks (i.e., to provide no transit service), and customer networks only want to carry traffic to/from itself. Suppose C has advertised path Cy to A. To implement this policy, to which of the following networks would network A advertise the path ACy?

5.4.2

5.4-4 PATH ADVERTISEMENT AND POLICY (PART 3).

Again, suppose a provider network only wants to carry traffic to/from its customer networks (i.e., to provide no transit service), and customer networks only want to carry traffic to/from itself. Suppose C has advertised path Cy to x. To implement this policy, to which of the following networks would network x advertise the path xCy?

5.4.2

5.4-5 EBGP OR IBGP?

Consider routers 2c and 2d in Autonomous System AS2 in the figure below. Indicate the flavor of BGP and the router from which each of 2c and 2d learns about the path to destination x

5.4.5

5.5-1 SDN LAYERS.

Consider the SDN layering shown below. Match each layer name below with a layer label (a), (b) or (c) as shown in the diagram

5.5.1

5.5-2 INTERNAL STRUCTURE OF THE SDN CONTROLLER (1).

Which of the functions below belong in the controller layer labeled "Interface, abstractions for network control apps"? Check all below that apply.

5.5.2

5.5-3 INTERNAL STRUCTURE OF THE SDN CONTROLLER (2).

Which of the functions below belong in the controller layer labeled "Network-wide distributed, robust state management"? Check all below that apply

5.5.2

5.5-4 INTERNAL STRUCTURE OF THE SDN CONTROLLER (3).

Which of the functions below belong in the controller layer labeled "Communication to/from controlled device"? Check all below that apply.

5.5.2

5.6-1 ICMP: INTERNET CONTROL MESSAGE PROTOCOL.

Which of the statements below about ICMP are true?

6.1-1 LINK-LAYER SERVICES.

Which of the following services may be implemented in a link-layer protocol? Select one or more statements.

6.2-1 TWO DIMENSIONAL PARITY.

Which of the following statements is true about a two-dimensional parity check (2D-parity) computed over a payload?

6.3-1 CHANNEL PARTITIONING PROTOCOLS.

Which of the following statements is true about channel partitioning protocols?

6.3-2 PURE ALOHA AND CSMA.

Which of the following statements is true about both Pure Aloha, and CSMA (both with and without collision detection?

6.3-3 POLLING AND TOKEN-PASSING PROTOCOLS.

Which of the following statements is true about polling and token-passing protocols?

6.3-4 CHARACTERISTICS OF MULTIPLE ACCESS PROTOCOLS (A).

Consider the following multiple access protocols that we've studied: (1) TDMA, and FDMA (2) CSMA (3) Aloha, and (4) polling. Which of these protocols are collision-free (e.g., collisions will never happen)?

6.3-5 CHARACTERISTICS OF MULTIPLE ACCESS PROTOCOLS (B).

Consider the following multiple access protocols that we've studied: (1) TDMA, and FDMA (2) CSMA (3) Aloha, and (4) polling. Which of these protocols requires some form of centralized control to mediate channel access?

6.3-6 CHARACTERISTICS OF MULTIPLE ACCESS PROTOCOLS (C).

Consider the following multiple access protocols that we've studied: (1) TDMA, and FDMA (2) CSMA (3) Aloha, and (4) polling. For which of these protocols is the maximum channel utilization 1 (or very close to 1)?

6.3-7 CHARACTERISTICS OF MULTIPLE ACCESS PROTOCOLS (D).

Consider the following multiple access protocols that we've studied: (1) TDMA, and FDMA (2) CSMA (3) Aloha, and (4) polling. For which of these protocols is there a maximum amount of time that a node knows that it will have to wait until it can successfully gain access to the channel?

6.4-1 DIFFERENT TYPES OF ADDRESSING (A).

We've now learned about both IPv4 addresses and MAC addresses. Consider the address properties below, and use the pulldown menu to indicate which of these properties is only a property of MAC addresses (and therefore is not a property of IPv4 addresses - careful!).

6.4-2 DIFFERENT TYPES OF ADDRESSING (B).

We've now learned about both IPv4 addresses and MAC addresses. Consider the address properties below, and use the pulldown menu to indicate which of these properties is only a property of IPv4 addresses (and therefore is not a property of MAC addresses - careful!).

6.4-3 DIFFERENT TYPES OF ADDRESSING (C).

We've now learned about both IPv4 addresses and MAC addresses. Consider the address properties below, and use the pulldown menu to indicate which of these properties is a property of both IPv4 addresses and MAC addresses.

6.4-4 FIELDS IN AN ETHERNET FRAME.

Use the pulldown menus below to match the name of the field with the function/purpose of a field within an Ethernet frame.

6.4-5 SWITCH FORWARDING AND FILTERING.

Suppose an Ethernet frame arrives to an Ethernet switch, and the Ethernet switch does not know which of its switch ports leads to the node with the given destination MAC address? In this case, what does the switch do?

6.4-6 SELF-LEARNING SWITCHES.

Which of the following statements are true about a self learning switch?

6.4-7 LEARNING SWITCH SCENARIO.

Consider the simple star-connected Ethernet LAN shown below, and suppose the Ethernet switch is a learning switch, and that the switch table is initially empty. Suppose C sends an Ethernet frame address to C' and C ' replies back to C. How many of these two frames are also received at B's interface?

6.4.7

6.4-8 LEARNING SWITCH STATE REMOVAL.

Consider the simple star-connected Ethernet LAN shown below, and suppose the switch table contains entries for each of the 6 hosts. How will those entries be removed from the switch table?

6.4.7

6.4-9 MAC ADDRESSES (VERSUS OTHER TYPES OF ADDRESSES AND IDENTIFIERS).

Which of the following statements are true about MAC (link-layer) addresses? Select one or more statements below.