Networking II - Chapter 3

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?

The forwarding node drops the packet and sends an ICMPv6 Packet Too Big message to the sending node.

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?

The values can be set to allow more fragmentation or prohibit more fragmentation, depending on the network's requirements.

In IPv6, any extension header must be inserted between the IP header and any higher-layer protocol headers.

True

The IPv4 header length is always a multiple of 32 bits.

True

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.

True

The IPv4's Time to Live (TTL) field is the remaining distance that the packet can travel. Though defined in terms of seconds, the TTL value is implemented as a number of hops that a packet can travel before being discarded by a router.

True

The Internet Protocol (IP) primarily works to transmit and deliver data between devices on internetworks.

True

Though defined in terms of seconds, a TTL value is implemented as a number of hops that a packet can travel before being discarded by a router.

True

The _____ field provides error detection on the contents of the IPv4 header only.

header checksum

What is a valid proposed option for the IPv6 Hop-by-Hop Options extension header?

jumbogram large payload options

UDP employs flow control in order to determine when packets have been lost and need to be sent again.

False

Unlike IPv4 packets, IPv6 packets ensure that data or application information is successfully transported from a source to a destination node on a network.

False

When a packet is sent between two ECN-capable routers, the packet is usually marked ECT(0) or ECT(10) for ECN Capable Transport.

False

The _____ extension header provides a method for extending the IPv6 header to support options for packet handling and preferences.

Destination Options

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) -Hop Limit -Destination Address -Identification -Source Address -Flow Label

-Destination Address -Source Address -Flow Label

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) -EGP -Ethernet -OSPF -ICMP -NAND

-EGP -OSPF -ICMP

The last bit of the entire Type of Service field is reserved and set at 0, as specified by RFC _____.

1349

There are _____ fields possible in the IPv4 header.

14

Because the options are rarely used, the size of the IPv4 header is typically _____ bytes.

20

In IPv4 the maximum time to live value is _____.

255

RFC _____ is the proposed standard for the Flow Label specification and defines the minimum requirements for this field.

3697

The fixed IPv6 header makes the first _____ octets or 320 bits of the IPv6 packet.

40

In IPv6, the _____ extension header should be used to encrypt data.

Encapsulating Security Payload

_____ was designed to provide devices with a method for notifying each other that a link is experiencing congestion before the routers start to drop packets.

Explicit Congestion Notification

Because PHB is independent of how individual routers are configured, the end-to-end behavior of traffic is predictable.

False

The Transport Relay Translator (TRT) system is prone to misconfigured network nodes, which results in poor performance.

False

RFC 2460 defines the recommended order in which extension headers should appear. Which extension header should appear first if it is present?

Hop-by-Hop Options

For the IPv6 header Traffic Class field, what function does the Precedence field serve?

It allows an application to differentiate traffic types based on priorities.

In IPv6, each extension header is identified by a specific _____ value.

Next Header

The 8-bit _____ field specifies the header type of the header immediately following the IPv6 header.

Next Header

The _____ field defines the length of the IP header and any valid data (although it does not include any data link padding).

None of these choices

Currently, the routing extension header is designed to use only one option. Which option can it use?

Routing Type = 0

In IPv6, a(n) _____ is a set of packets for which a source requires special handling by the intervening routers.

flow

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 don't lower the priority value. Of the following, which service most requires DSCP EF?

VoIP

How does the Authentication extension header specify the true origin of an IPv6 packet?

by preventing address spoofing and connection theft

IPv6 routers can reference the _____ bits to determine how to prioritize traffic through the router processing and queuing system.

precedence

The _____ was one early attempt to promote a more formal approach to dynamic resource allocation on the Internet.

resource reservation protocol

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?

the larger IPv6 address space

In an IPv4 packet header, what does the value in the Internet Header Length signify?

the length of the IPv4 header

Which address type can the Source Address field of an IPv4 packet header contain?

unicast