protocol analysis Quiz 3

• Question 1

In an IPv4 packet header, what does the value in the Internet Header Length signify?
Selected Answer:
the length of the IPv4 header
Correct Answer:
the length of the IPv4 header

• Question 2

RFC 2460 defines the recommended order in which extension headers should appear. Which extension header should appear first if it is present?
Selected Answer:
Hop-by-Hop Options
Correct Answer:
Hop-by-Hop Options

• Question 3

What basic function does the IPv4 Header Checksum field perform?
Selected Answer:
It provides error detection on the contents of the IP header, minus the Checksum field.
Correct Answer:
It provides error detection on the contents of the IP header, minus the Checksum field.

• Question 4

The Flags field in an IPv4 header can be set to different values, depending on fragmentation requirements. Of the following, which is correct about the options that can be set in this field?
Selected Answer:
The values can be set to allow more fragmentation or prohibit more fragmentation, depending on the networkâ s requirements.
Correct Answer:
The values can be set to allow more fragmentation or prohibit more fragmentation, depending on the networkâ s requirements.

• Question 5

The IPv4 Protocol field contains the value of the protocol that is coming next. Of the following, which are valid protocols for this field? (Choose all that apply.)
Selected Answers:
EGP

ICMP

OSPF
Correct Answers:
EGP

ICMP

OSPF

• Question 6

When is the Fragment extension header used?
Selected Answer:
when the transmitting device needs to send packets larger than the PMTU
Correct Answer:
when the transmitting device needs to send packets larger than the PMTU

• Question 7

Currently, the Routing extension header is designed to use only one option. Which option can it use?
Selected Answer:
Routing Type = O
Correct Answer:
Routing Type = O

• Question 8

How does the Authentication extension header specify the true origin of an IPv6 packet?
Selected Answer:
by preventing address spoofing and coincorrectection theft
Correct Answer:
by preventing address spoofing and coincorrectection theft

• Question 9

Of the following, which extension header can appear more than once for an IPv6 packet?
Selected Answer:
Destination Options
Correct Answer:
Destination Options

• Question 10

What is a valid proposed option for the IPv6 Hop-by-Hop Options extension header?
Selected Answer:
jumbogram large payload options
Correct Answer:
jumbogram large payload options

• Question 11

The Next Header field in the IPv6 header points to the first extension header for the packet if the packet possesses one or more extension headers. If more than one extension header exists, how is this extension header identified?
Selected Answer:
The Next Header field points to the first extension header and, if others exist, the first extension header uses its own Next Header field to point to the next extension header.
Correct Answer:
The Next Header field points to the first extension header and, if others exist, the first extension header uses its own Next Header field to point to the next extension header.

• Question 12

Which fields in an IPv6 header do packet classifiers use to identify a packet’s flow if it is part of a flow? (Choose all that apply.)
Selected Answers:
Destination Address

Flow Label

Source Address
Correct Answers:
Destination Address

Flow Label

Source Address

• Question 13

For the IPv6 header Traffic Class field, what function does the Precedence field serve?
Selected Answer:
It allows an application to differentiate traffic types based on priorities.
Correct Answer:
It allows an application to differentiate traffic types based on priorities.

• Question 14

A network node that understands the Jumbo Payload option will process a packet as a jumbogram under what condition?
Selected Answer:
The Link-Layer framing indicates that additional octets exist beyond the IPv6 header.
Correct Answer:
The Link-Layer framing indicates that additional octets exist beyond the IPv6 header.

• Question 15

IPv6 packet headers are much larger in size than IPv4 packet headers, even though the IPv6 header structure is less complex. What is the main cause of the size increase?
Selected Answer:
the larger IPv6 address space
Correct Answer:
the larger IPv6 address space

• Question 16

When ruincorrecting UDP over IPv6, the checksum is mandatory and a pseudo-header is used to imitate the actual IPv6 header. If the Routing extension header is present, what is the result in the pseudo-header?
Selected Answer:
The address in the Destination Address field is the final destination address.
Correct Answer:
The address in the Destination Address field is the final destination address.

• Question 17

Which address type can the Source Address field of an IPv4 packet header contain?
Selected Answer:
unicast
Correct Answer:
unicast

• Question 18

When is the Destination Options extension header encrypted?
Selected Answer:
when it appears later in the packet
Correct Answer:
when it appears later in the packet

• Question 19

Using the differentiated service code point (DSCP) identifier, IPv4 traffic can be prioritized by an end node or boundary device, such as a router, and queued and forwarded according to this value. DSCP expedited forwarding (EF) ensures that routers expedite the packet forwarding and donâ t lower the priority value. Of the following, which service most requires DSCP EF?
Selected Answer:
VoIP
Correct Answer:
VoIP

• Question 20

What is the purpose of the Precedence bits in the IPv4 header’s “Type of Service” field?”
Selected Answer:
Precedence is used by routers to prioritize traffic through router queues.
Correct Answer:
Precedence is used by routers to prioritize traffic through router queues.

• Question 21

The IPv4’s Time to Live (TTL) field indicates the remaining lifetime of the packet defined as distance or as in hops through routers.
Selected Answer:
False
Correct Answer:
False

• Question 22

In an IPv4 Packet header, the Identification field contains a unique identifier for each packet; however, packets are sometimes fragmented further by routers to transverse a network that supports a smaller packet size. What happens to the value of the Identification field in a packet header if the packet is further fragmented?
Selected Answer:
Each fragment of the original packet maintains the original ID value in the header Identification field.
Correct Answer:
Each fragment of the original packet maintains the original ID value in the header Identification field.

• Question 23

The IPv4 header’s Options field provides additional IP routing controls. What is the boundary where the options must end?
Selected Answer:
4-byte boundary
Correct Answer:
4-byte boundary

• Question 24

Once PMTU Discovery sets the MTU size for IPv6 packets and begins sending, how do forwarding nodes manage packets if a link MTU in the path reduces or becomes too small for the packet MTU size?
Selected Answer:
The forwarding node drops the packet and sends an ICMPv6 Packet Too Big message to the sending node.
Correct Answer:
The forwarding node drops the packet and sends an ICMPv6 Packet Too Big message to the sending node.

• Question 25

The IPv4 header’s Fragment Offset field is used, if the packet is a fragment, to show where to place the packet’s data when the fragments are reconstructed.
Selected Answer:
True
Correct Answer:
True