CIS 321 Exam 3
fields
(1) a subdivision of a message header or trailer. (2) an IPv6 field is a group of lowercase hexadecimal symbols. each field represents 16 bits. fields are separated by colons.
cable modem
(1) broadband data transmission service using cable television. (2) the modem used in this service
handoff
(1) in a wireless LAN, a change in access points when a user moves to another location. (2) in cellular telephony, transfer from one cellsite to another, which occurs when a subscriber moves from one cell to another within a system
routing
(1) the forwarding of IP packets. (2) the exchange of routing protocol information through routing protocols.
In the mask /14, how many 1s are there?
14
If your subnet part is 8 bits long, you can have ________ subnets.
254
Deciding what interface and to what device to send the packet back out is step ________ in the routing process.
3
A mask has ________ bits.
32
If the subnet ID in an IPv6 address is 32 bits, how long is the routing prefix?
32 bits
The DNS ________ record is for the host name's ________ address
A; IPv4
Which of the following does the carrier NOT own?
B. customer premises equipment
Corporations wish to have ________ domain names.
B. second-level
To use a leased line, the customer must have a(n) ________ at each site.
C. CSU/DSU
In a telephone system, the lines that connect customers to the nearest switch are called ________.
D. the local loop
Four-way closes use ________ segments.
FIN
Which of the following is the most expensive to use?
MPLS
An abrupt close uses a ________ segment.
RST
Which is less expensive to implement?
SSL/TLS
In SNMP, companies are often reluctant to use ________ commands because of security dangers.
Set
In the IPv4 address 1.2.3.4, what is the network part?
We cannot say.
Which is a problem with IPv4 addresses? A. They are incompatible with wireless devices. B. They are too complex. C. Routers find it difficult to handle them. D. We have run out of them.
We have run out of them.
metropolitan area network
a WAN that spans a single urban area
mobile telephone switching office
a control center that connects cellular customers to one another and to wired telephone users, as well as overseeing all cellular calls (determining what to do when people move from one cell to another, including which cellsite should handle a caller when the caller wishes to place a call.)
echo reply
a message that responds to an Echo message
prefix notation
a way of representing masks; gives the number of initial 1s in the mask. a mask is represented by a slash followed by the number of initial 1s in the mask.
exploit
act of breaking into a computer, the method used to break in, or the crimeware software used to break in
In SNMP, the manager communicates directly with a(n) ________.
agent
two-way amplifiers
amplifier that amplifies signals in both directions
private IP address ranges
an IP address that may be used only within a firm. there are three designated ranges.
security association
an agreement between two parties on the security methods and parameters they will use in their subsequent interactions
object
an aspect of a managed device about which data is kept
root
at the top of the DNS hierarchy consisting of all domain names
internet service provider
carrier that provides internet access and transmission
Which of the following receive rights of way for transmission beyond sites?
carriers
Two-way amplifiers are needed for cable ________ service.
data
If no other row matches, the router will select the ________ row as its best match.
default
traffic engineering
designing and managing traffic on a network
cellsite
equipment at a site near the middle of each cell, containing a transceiver and supervising each cellphone's operation
lower-level domains
further qualified domains. ex. shidler.hawaii.edu
e-line service
gives an ethernet connection between two sites, effectively connecting them into a single ethernet network
e-LAN service
gives ethernet connections between multiple sites, effectively connection them into a single ethernet network
If a router receives 20 packets in a row going to the same destination IP address, the standard calls for it to ________.
go through all three steps for each
For human reading, IPv6 addresses are written in ________ notation.
hexadecimal
hop limit fields
in IPv6, the field that limits the number of hops an IPv6 packet may make among routers.
sequence number fields
in TCP, a header field that tells a TCP segment's order among the multiple TCP segments sent by one side.
acknowledgment number fields
in TCP, a header field that tells what TCP segment is being acknowledged in a segment.
default row
in general, a "default" is something you get if you do not have a more specific choice; the row of a routing table that will be selected automatically if no other row matches. its value is 0.0.0.0.
Router ports are called ______.
interfaces
traffic shaping
limiting access to a network based on type of traffic
ADSL modem
modem used in asynchronous digital subscriber line service. terminantes the carrier's connection
WAN optimization devices
network device that optimizes wide area network traffic through compression and other methods. desirable because WAN traffic is more expensive than LAN traffic per bit transmitted.
A border router connects different IP ________ and an internal router connects different IP ________.
networks, subnets
fiber to the home
optical fiber brought by carriers to individual homes and businesses
label switched path
path that all packets to a particular address will take across and MLPS label-switched network
compression
reducing the number of bits needed to be transmitted when the traffic has redundancy that can be removed
For cost reasons, you should ________ where you can, ________ where you must.
switch; route
channel reuse
the ability to use each channel multiple times in different cells in the network
head end
the cable television operator's central distribution point
network core
the central part of a network
time to live (TTL) field
the field added to a packet and given a value by the source host, usually between 64 and 128. each router along the way decrements the TTL field by one. a router decrementing the TTL to zero will discard the packet; this prevents misaddressed packets from circulating endlessly among packet switches in search of their nonexistent destinations
class 5 switches
the switch at the lowest level switching hierarchy. subscribers connect to these switches
second-level domains
the third level of a DNS hierarchy that specifies the organization
host to host VPN
virtual private network that creates cryptographically protected connections between an individual host and a corporate site.
site to site VPN
virtual private network that secures all communication between two sites
carrier WANs
wide area networking services offered by a carrier
In the mask 255.255.255.0, how many 1s are there?
24
How does carrier Ethernet differ from traditional Ethernet?
A. It is offered by carriers instead of being installed and managed by the company using it. B. It is for MAN and WAN services.
Why is Carrier Ethernet popular?
A. It uses familiar technology. B. It has attractive prices.
A company has a domain name. What else must it have before it can make a website available to the public?
A. a DNS server to host its domain name B. the website itself
WAN optimization devices are deployed ________.
A. at the ends of leased lines
Which of the following affects what cellular throughput an individual user will receive?
A. being in a moving car B. being far from the cellsite
An MTSO ________.
A. controls cellsites in a cellular system B. links mobile users to wired telephone customers
Compared to ADSL service, cable modem traditionally has been ________.
A. faster and more expensive
A WAN is the network that ________.
A. links different sites together
Compared to the Internet, carrier WANs ________.
A. offer higher-quality service
Traffic shaping reduces traffic by ________.
A. preventing certain undesirable traffic from entering the network B. limiting the amount of certain undesirable traffic entering the network
IPsec is used for ________ VPNs.
A. remote-access B. site-to-site
In ADSL, the customer should have ________.
A. splitters B. an ADSL modem
An advantage of using DHCP to configure clients is that ________.
A. the configuration information will be up-to-date
DSL offers ________.
A. voice transmission B. data transmission
NAT ______________. A. allows a firm to have more internal IP addresses B. provides some security C. both A and B D. neither A nor B
C. both A and B
The domain name system ________. A. is a way to find a host's IP addresses if your computer only knows the host's host name B. is a general naming system for the Internet C. both A and B D. neither A nor B
C. both A and B
For their transmission medium, cable television companies primarily use ________.
C. coaxial cable
Which is NOT one of the three parts of a public IPv6 unicast address? A. subnet ID B. routing prefix C. host part D. All of the above are parts in a public IPv6 unicast address.
C. host part
The PSTN core is organized as a ________.
C. modified hierarchy
What transmission medium do ALL DSL services use?
C. one-pair voice-grade UTP
echo request
ICMP message that asks a host to send back an echo reply message. this lets the sender know that the other device is reachable and also gives the round-trip latency to that device
SA protections are applied in the ________.
IPsec protection
________ is the process of presenting external IP addresses that are different from internal IP addresses used within the firm.
NAT
DSL access multiplexer
a device at the end office of a telephone company that sends voice signals over the ordinary PTSN and sends data over a data network such as an ATM network
domain
a group of resources (routers, single networks, and hosts) under the control of an organization
leased lines
a high-speed, point to point, always on connection
decision cache
a list a router keeps of recent routing decisions for specific IP addresses so that it does not have to go through the entire routing decision again if another packet to that IP address arrives. this is nonstandard and somewhat risky.
wide area network
a network that links different sites together
local area network
a network within a customer's premises
metric
a number describing the desirability of a route represented by a certain row in a routing table
flag fields
a one-bit field
sniffer program
a program that intercepts traffic to read it in order to find information useful to an attacker
border router
a router that sits at the edge of a site to connect the site to the outside world through leased lines, PSDNs, and VPNs. its main job is to connect different networks.
next-hop router
a router to which another router forwards a packet in order to get the packet a step closer to reaching its destination host
domain name system
a server that provides IP addresses for users who know only a target host's host name. DNS servers also provide a hierarchical system for naming domains.
subnet
a small network that is a subdivision of a large organization's network
management information base
a specification that defines what objects can exist on each type of managed device and also specifies characteristics of each object; the actual database stored on a manager in SNMP. there are separate MIBs for different types of managed devices; both a schema and a database.
IPv4 mask
a string of 32 bits, beginning with a series of 1s and follows by a series of 0s; used by routers to assign routes to all packets going to a particular network or subnet on a network.
IPsec gateway
border device at a site that converts internal traffic data into protected traffic data that travels over an untrusted system such as the Internet
domain registrars
companies that allow individuals and organizations to purchase the right to use a particular second-level domain name on the Internet
The first step in the routing process involves ________.
comparing the packet's destination IP address to all rows
OSPF dynamic routing protocol
complex, but highly scalable interior routing protocol
ICMP error advisement
contains type and code values indicating what the problem is. not error correction. only sent to help the sending process or its human user diagnose problems.
network address translation
converting an IP address into another IP address, usually at a border firewall; disguises a host's true IP address from sniffers. Allows more internal addresses to be used than an ISP supplies a firm with external addresses
coaxial cable
copper transmission medium in which there is a central wire and a coaxial metal tube as the second connector
CSU/DSU
device on a customer premises that terminates a carrier's transmission line. carrier service unit/data service unit
routers
devices that forwards packets within an internet. routers connect two or more single networks (subnets).
asymmetric
different in two directions
ICMP control messages
directs a device to change how it operates. echo request and echo reply messages.
load balancing
dividing traffic across routers in order not to overload any single route
customer premises equipment
equipment owned by the customer, including PBXs, internal vertical and horizontal wiring, and telephone handsets
carrier ethernet
ethernet service provided in a MAN or WAN by a carrier to user organizations.
In IPv6 addresses, ________ are separated by ________.
fields; colons
One-bit fields are called ________ fields and if it is not set, this means its value is ______.
flag, 0
label number
number in the label header that aids label-switching routers in packet sending
tunnel mode
one of IPsec's two modes of operation, in which the IPsec connection extends only between IPsec gateways at the two sites. tunnel mode provides no protection within sites, but it offers transparent security.
transport mode
one of IPsec's two modes of operation, in which the two computers that are communicating implement IPsec. transport mode give strong end-to-end security between the computers, but it requires IPsec configuration and a digital certificate on all machines
internal router
only connects different subnets within a network; a router that connects different LANs within a site.
IPsec
protects communication using encapsulating security protocol and authentication header.
internet control message protocol
protocol created by the IETF to oversee supervisory messages at the internet layer
simple network management protocol
protocol that allows a general way to collect rich data from various managed devices in a network
dynamic routing protocol
protocol that allows router to exchange routing table information
dynamic host configuration protocol
protocol used by DHCP servers, which provide each user PC with a temporary IP address to use each time he or she connects to the Internet
interior dynamic routing protocols
protocol used within a firm's internet
digital subscriber line
provides digital data signaling over the residential customer's existing single-pair UTP voice-grade copper access line
interfaces
router ports that must be designed for the network to which it connects
label switching router
router that implements MPLS label switching
Dynamic ________ protocols allow routers to transmit routing table information to one another.
routing
In a routing table, a ________ represents a route for a group of IP addresses.
row
synchronous DSL
same speed in both directions. normally used in business
The second step in the routing process involves ________.
selecting the best-match row
cells
small, geographical region served by a cellsite
caching
storing very temporary information for retrieval. in routing, storing routing decisions for particular IP addresses that were recently handled instead of going through the entire routing process again.
local loop
the line used by a customer to reach the PTSN's central transport core
access links
the line used by the customer to reach the PTSN's central transport core
border gateway protocol
the most common exterior routing protocol on the internet. gateway = router
end office switches
the nearest switch to the telephone company to the customer premises
default router
the next-hop router that a router will forward a packet to if the routing table does not have a row that governs the packet's IP address except for the default row.
top-level domains
the second level of a DNS hierarchy, which organizes the domain by organization type or by country.
asymmetrical digital subscriber line
the type of DSL designed to go into residential homes, offers high downstream speeds, but limited upstream speed
public switched telephone network
the worldwide telephone network
".com" is a ________.
top-level domain
multiprotocol label switching
traffic management tool used by many ISPs
TCP/IP standards are set at the ________.
transport layer
