Network+ Guide to Networks (7th edition) chapter 3

What type of routing protocol enables routers to communicate beyond neighboring routers, allowing each router to create a map of an entire network??

link state

UDP provides error checking, but not sequencing.? t/f

FALSE

What netstat command option lists only current connections, including IP addresses and port numbers?

#NAME?

Which of the following is not a task handled by a router?

A router forwards broadcasts over the network.

When viewing the routing table on a UNIX system, what flag indicates if a route is a usable route??

?U

What IPv4 protocol handles multicasting for tasks such as videoconferencing or teleconferencing??

IGMP?

?Which network routing protocol is a path vector protocol that sends updates between routers using TCP?

?BGP

ARP (Address Resolution Protocol) works in conjunction with IPv4 to discover the MAC (physical) address of a host or node on the local network and to maintain a database that
maps IP addresses to MAC addresses on the local network. ARP is a Layer 2 protoc

ARP relies on broadcasting, which transmits simultaneously to all nodes on a particular network
segment. For example, if one node needs to know the MAC address of another node
on the same network, the first node issues a broadcast message to the network, using ARP, that essentially says,

Will the computer with the IP address 1.2.3.4 please send me its MAC address?" The node that has the IP address 1.2.3.4 then transmits a reply that contains the physical address of the destination host.

The database of IP-to-MAC address mappings is called an ARP table (also called an ARP
cache) and is kept on a computer's hard drive. Each OS can use its own format for the ARP
table.

On IPv4 networks, IGMP (Internet Group Management Protocol or Internet Group Multicast
Protocol) operates at the Network layer of the OSI model to manage multicasting. Unlike a broadcast transmission, a multicast transmission does not necessarily issue tr

Multicasting can, for example, be used for teleconferencing or
videoconferencing over the Internet. Routers use IGMP to determine which nodes belong to a
certain multicast group and to transmit data to all nodes in that group. Network nodes use
IGMP to join or leave multicast groups at any time.

Dynamic ARP table
entries are created when a client makes an ARP request that could not be satisfied by data

created when a client makes an ARP request that could not be satisfied by data already in the ARP table.

Static ARP table entries

are those that someone has entered manually using the ARP utility. This ARP utility, accessed via the arp command from a Windows command prompt or a UNIX or Linux shell prompt,

Recall that the first half of a MAC address can be used to

identify the manufacturer of that
NIC, which may help you in identifying a NIC among other NICs

Interior routers

direct data between networks within the same autonomous system.

autonomous system (AS)

is a group of networks, often on the same domain, that are
operated by the same organization. For example, Cengage, the company that published this book, might have several LANs that all fall under the cengage.com domain, with each LAN connected to the others by interior routers.

Border routers (or gateway routers)

connect an autonomous system with an outside network.
For example, the router that connects a business with its ISP is a border router.

Exterior routers

direct data between autonomous systems. Routers that operate on the Internet backbone are considered exterior routers. An exterior router can also be a border or gateway router if it stands between an autonomous system and an outside network.

Multilayer Switches. Layer 3 switch

switch that is capable of interpreting Layer 3 data and works much like a router: It supports the same routing protocols and makes routing decisions. Layer 3 switches were designed to work on large LANs, similar to interior routers, except they're faster and less
expensive.

What is NOT one of the three characteristics of TCP in its role as a reliable delivery protocol??
Selected Answer:
Incorrecta. ?Flow Control
a. ?Flow Control
b. ?Framing
c. ?Connection-oriented Protocol
d. ?Sequencing and checksums

framing

As a network support technician, you only need to know how to support IPv6. t/f

FALSE

What field in an IPv4 packet informs routers the level of precedence they should apply when processing an incoming packet?

Differentiated Services (DiffServ)

In a TCP segment, what field indicates how many bytes the sender can issue to a receiver while acknowledgement for the segment is outstanding??

sliding window

?What command can be used on a Cisco router to view the routing table?

show ip route

Which of the following is not a task handled by a router?
a. ?A router can reroute traffic if the path of first choice is down but a second path is available.
b. ?A router can connect dissimilar networks.
c. ?A router can interpret Layer 3 and often Layer

A router forwards broadcasts over the network.

What TCP field below allows the receiving node to determine whether a TCP segment is corrupted during transmission??

?checksum

In IPv6, what field is used to indicate what sequence of packets from one source to one or multiple destinations a packet belongs to??

flow label

What happens when a router receives a packet with a TTL of 0??

?The router drops the packet and sends an ICMP TTL expired message back to the host.

?Which network routing protocol is a path vector protocol that sends updates between routers using TCP?

?BGP

IP is an unreliable, connectionless protocol.? t/f

TRUE

What parameter can be combined with the traceroute command to instruct it to use ICMP echo requests instead of UDP datagrams??

#NAME?

By default, the pathping command sends how many pings per hop??

100

What protocol replaces ARP, IGMP, and ICMPv4 on IPv6 based networks??

ICMPv6

The IP connectionless protocol relies on what other protocol to guarantee delivery of data?

?TCP

What is NOT one of the three characteristics of TCP in its role as a reliable delivery protocol??

?Framing

A modern ASN consists of how many bits?

32

What routing protocol criteria is defined as the time it takes to recognize a best path change in the event of a network outage?

convergence time

The primary difference is the way the hardware is built, but, in fact, it's often hard

to distinguish between a Layer 3 switch and a router. In some cases, the difference comes down to what the manufacturer has decided to call the device in order to improve sales.

Layer 4 switches also exist and are capable of interpreting Layer 4 data. They operate anywhere between Layer 4 and

Layer 7 and are also known as content switches or application switches. Among other things, the ability to interpret higher-layer data enables switches to perform advanced filtering, keep statistics,

and provide security functions. The features of Layer 3
and Layer 4 switches vary widely depending on the manufacturer and price and can cost three times more than

Layer 2 switches. This variability is exacerbated by the fact that key players in
the networking trade have not agreed on standards for these switches

They are typically used as part of a network's backbone and are not appropriate on a LAN.

In general, however,
Layer 4, Layer 3, and Layer 2 switches are all optimized for fast Layer 2 data handling.

A routing table is a database that maintains information about where hosts are located and the
most efficient way to reach them. A router relies on its routing table to identify which

router is
the next hop to reach a particular destination host. The routing table contains IP addresses and
network masks that identify a network that a host or another router belongs to.

Static routing is a technique in which a network administrator configures a routing

table to direct messages along specific paths between networks.

Static routes are appropriate
in certain situations, such as the static route between a small business and its ISP. However, static routes

used to traverse several networks don't account for occasional network congestion, failed connections, or device moves, and they require human intervention.

Dynamic routing, on the other hand, automatically calculates the best path between two networks
and accumulates this information in the routing table. If congestion or failures affect
the network, a router using dynamic routing

can detect the problems and reroute messages
through a different path. By default, when a router is added to a network, dynamic routing
ensures that the new router's routing tables are updated.

Most networks primarily use dynamic routing, butmay include some static routing to indicate, for
example, a gateway of last resort, which is

the router that accepts all unroutable messages from
other routers.When a router cannot determine

a path to a message's destination, the router sends
the message along a default route, usually to another router. This

next router will also attempt to
determine a path for the message, but is also programmed with a default route if a path cannot be

determined. The routers will continue resorting to default routes until the hop

limit is depleted or
until a path can be determined and the destination is reached,whichever comes first

Messages are sent to a default gateway�a router or Layer 3 switch�when their
destination is not on the host's local network.

A default route is a backup route when no other route can be determined.
The default route points to the gateway of last resort, which is the router
assigned to receive unroutable messages from other routers.

On IPv4 networks, IGMP operates at the Network layer of the OSI model to manage multicasting. t/f

TRUE

ASN

autonomous system number
now consists of 32 bits, and they are assigned by IANA

OSPF (Open Shortest Path First

IGP and a link-state routing protocol used on
interior or border routers. It was introduced as an improvement to RIP and can coexist with
RIP (or RIPv2) on a network. Unlike RIP, OSPF imposes no hop limits

IS-IS (Intermediate System
to Intermediate System

uses a best-path algorithm similar to OSPF's and was originally codified by ISO, which referred to routers as "intermediate systems,

BGP (Border Gateway Protocol

can span multiple autonomous systems and is used by border and exterior routers on the Interne

pathping

combines elements of both ping and tracert to
provide deeper information about network issues along a route. It sends multiple pings to
each hop along a route, then compiles the information into a single report.

TCP (Transmission Control Protocol) is an OSI Transport layer, connection-oriented
protocol that requires a connection to be established between communicating nodes
before it will transmit data. TCP provides reliability through checksum, flow control,
and

UDP (User Datagram Protocol), like TCP, is a Transport layer protocol. UDP is a
connectionless service and offers no delivery guarantees. But UDP is more efficient
than TCP and useful in applications that require fast data transmission, such as
videoconferencing.

IP (Internet Protocol) belongs to the Network layer of the OSI model and provides
information about how and where data should be delivered

ARP (Address Resolution Protocol) belongs to the Data Link layer of the OSI model.
It obtains the MAC (physical) address of a host, or node, and then creates a local
database that maps the IP (logical) address to the host's MAC (physical) address.

ICMP (Internet Control Message Protocol) is a Network layer core protocol that
reports on the success or failure of data delivery, although it does not correct the

errors that it detects. On IPv6 networks, ICMPv6 detects and reports data transmission errors, discovers other nodes on a network, and manages multicasting.

A router is a multiport device that can connect dissimilar LANs and WANs running
at different transmission speeds, using a variety of

protocols. Routers interpret logical
addresses and determine the best path between nodes. They operate at the Network
layer (Layer 3) or higher of the OSI model.

Static routing is a technique in which a network administrator programs a router to
use specific paths between nodes. Dynamic routing automatically calculates the best
path between two nodes and accumulates this information

in a routing table. If congestion or failures affect the network, a router using dynamic routing can detect the
problems and reroute data through a different path. Most modern networks use
dynamic routing.

To determine the best path, routers communicate with each other through routing
protocols, including RIP, RIPv2, OSPF, IS-IS, and BGP. Different routing protocols
use different algorithms and routing metrics to choose the best path.

Routing metrics may factor in the number of hops between nodes, throughput, delay,
MTU, cost, load, and reliability.

RIP (Routing Information Protocol), a distance-vector routing protocol, is the slowest
and least secure routing protocol and limits transmissions to 15 hops. RIPv2 makes
up for some of the original RIP's overhead

and security limitations, but its forwarding
ability is limited to 15 hops. RIP belongs to the IGP (interior gateway protocol) category of protocols that can forward data only within an autonomous LAN.

OSPF (Open Shortest Path First) is a link-state routing protocol used on interior or
border routers. It was introduced as an improvement to RIP and can coexist with RIP
(or RIPv2) on a network.

Unlike RIP, OSPF imposes no hop limits on a transmission
path. Also, OSPF uses a more complex algorithm for determining best paths than RIP
uses.

IS-IS uses virtually the same methods as OSPF to calculate best paths, is less common,
and is limited to interior routers.

BGP (Border Gateway Protocol), designed primarily for routing over Internet backbones, uses the most complex best-path calculation of all the commonly used routing
protocols. It's considered an exterior routing protocol.

In a TCP segment, what field indicates how many bytes the sender can issue to a receiver while acknowledgement for the segment is outstanding??

?sliding window

?The IP connectionless protocol relies on what other protocol to guarantee delivery of data?

?TCP

?At what layer of the OSI model would a TCP or UDP header be added to a payload?

layer 4