Juniper Networking Fundamentals
802.3 - answer-802.3 is a networking standard established by the Institute of Electrical and Electronics
Engineers (IEEE). Among other things, 802.3 standardized the operation of CSMA/CD. While Ethernet
and 802.3 differ slightly in their terminology and their frame format, their media access control (MAC)
protocols are virtually identical. Today, the term Ethernet refers generically to both the sets of Ethernet
standards.
802.11 Group of Standards - answer-The 802.11 Group of Standards are specifications for wireless local
area networking. The original standard was released in 1997 and many extensions have been added
over the years.
Ack - answer-Ack is an abbreviation for Acknowledgement. It is the affirmative response of one device to
another in the connection establishment process.
Active Scanning - answer-In a wireless environment, active scanning is when a client probes for a
particular network in order to associate with it.
Address Resolution - answer-Address resolution is the process of using Layer 3 addresses to determine
Layer 2 addresses.
Address Resolution Protocol (ARP) - answer-In TCP/IP-based networks, the Address Resolution Protocol
is the protocol that manages the address resolution process.
Analog Lines - answer-Analog lines are the wires or cables used to carry analog signals, such as those in
your home telephone service. Analog lines are typically copper wire and operate at Layer 1 or the
Physical Layer. An analog signal is a continuous series of electrical pulses that vary over time, like waves.
Application Layer/Layer 7 (OSI REFERENCE MODEL) - answer-In the OSI Reference Model, the
Application Layer is Layer 7. It specifies network-related functions for a user application or program to
ensure that communication with another application or program over a network is possible. It's
important to note that this is not the user interface itself. When a user chooses to read email, transfer a
file, or surf the network, the user's software program, such as a Web browser, interacts with the
Application Layer. In the Five-Layer Model and the TCP/IP Model, the Application Layer has a broader
scope of functionality. In those models, it also includes the functionality of the OSI Reference Model's
Presentation Layer (Layer 6) and Session Layer (Layer 5).
Application Layer (FIVE-LAYER REFERENCE MODEL AND TCP/IP REFERENCE MODEL) - answer-The
Application Layer specifies network-related functions for a user application or program so that
communication with another program over a network is possible. It's important to note that this is not
the user interface itself. When a user chooses to read email, transfer a file, or surf the network, the
user's software program, such as a Web browser, interacts with the Application Layer. In the Five-Layer
Model and the TCP/IP Model, the Application Layer also manages encoding, data compression,
encryption, and sessions. In the OSI Reference Model, those functions are delegated to the Presentation
Layer and Session Layer.
,Asynchronous Transfer Mode (ATM) - answer-Asynchronous transfer mode (ATM) is a Layer 2 WAN
protocol that can transport voice, video, and data on the same network with guaranteed performance
or quality of service for each type of traffic. Customers can build a Virtual Private Network using ATM.
ATM Adaption Layer (AAL) - answer-The ATM Adaption Layer (AAL) is responsible for segmenting the
packet into fixed-length cells of 48 bytes each. The receiving device reassembles the cells into the
original packet.
Autonomous WLAN Architecture - answer-Autonomous architecture, also known as "Fat Access Point"
or "Fat AP" architecture, is a form of wireless LAN architecture where all functionality is coded into
every access point (wireless termination point).
Available Bit Rate (ABR) - answer-Available Bit Rate (ABR) is the ATM service category that is used by
applications, such as critical data transfers, that can dynamically adjust their data transmission rate in
response to network feedback. The goal of the ABR service is to allow application access to unused
network bandwidth.
Backward Explicit Congestion Notification (BECN) - answer-Backward Explicit Congestion Notification
(BECN) bits are bits in the Frame Relay header used to notify an end station, such as a router, of network
congestion. When congestion occurs, Frame Relay switches set the BECN bit to a one in frames going
back toward the source of traffic indicating that the sending router should slow down transmission until
the congestion subsides.
Base-10 System - answer-The base-10 system is a number system using ten digits—0 through 9—that
can be grouped together to form a decimal number. Each position within a decimal number represents a
power of 10.
Base-2 System - answer-Base-2 system is the binary number system that uses only two digits—0 and 1.
In the binary number system, each position represents a power of 2.
Binary - answer-Binary is a base-2 numbering scheme that uses only two digits—0 and 1—to represent
numbers. Each position represents a power of two. Routers and other computers work only with binary
numbers.
Bit - answer-Bit is the binary digit used in the binary numbering system. A bit is the most basic
information unit that computers use. A single bit is a "one" or a "zero", a "true" or a "false", or an "on"
or an "off".
Bridge - answer-A bridge is a Layer 2 network device that connects two or more physical cable segments
to create one larger network. Each side of the bridge becomes a separate collision domain or network
segment. So, a bridge can be used to break up a large network into separate collision domains. A bridge
builds a MAC address table that it uses to manage traffic flow. When a bridge receives data from an
unknown MAC address, it adds that address to its MAC address table and notes the port associated with
that address. Then, if a bridge later receives data for that address, it will know on which port it should
forward the data. If a bridge receives data for an unknown destination address, it will forward the data
on all ports, which is known as flooding. Bridges operate based on reading Layer 2 frame information
only. They cannot change Layer 2 addresses, and they do not have any access to Layer 3 data.
, Broadcast Address - answer-The broadcast MAC address is a special address used to send data to all
devices on the same network. The broadcast MAC address is ffff.ffff.ffff. Other types of MAC addresses
include unicast addresses and multicast addresses.
Broadcast Domain - answer-A broadcast domain is the group of devices that can be reached by sending
a frame addressed to the broadcast MAC address.
Bursty - answer-Bursty refers to data that transfers or transmits in short, uneven spurts. LAN traffic is
typically bursty.
Byte - answer-A byte is a group of 8 bits. It is also known as an octet.
Central Office (CO) - answer-Central Office (CO) is the term used to refer to the service provider's
nearest exchange. A CO is like a distribution center, sending data to other COs along the path to its final
destination.
Cell Loss Priority (CLP) - answer-Cell Loss Priority (CLP) is an ATM cell bit indicating which cells should be
discarded first, in the case of network congestion.
Cell Loss Ratio (CLR) - answer-Cell Loss Ratio (CLR) is the ATM QoS parameter for the percentage of cells
that are lost in the network because of error or congestion and that are not received by the destination.
Cell Transfer Delay (CTD) - answer-Cell Transfer Delay (CTD) is the ATM QoS parameter for the delay
experienced by a cell between the time it takes for the source to transmit the first bit of the cell and the
destination to receive the last bit of the cell.
Centralized (Switched) WLAN Architecture - answer-Centralized architecture, also known as a switched
WLAN system, is a form of wireless LAN architecture where a central switch or access point controller
manages multiple access points that are "Thin" or "Lightweight", meaning that they do not themselves
contain full LAN functionality.
Channel Service Unit/Data Service Unit (CSU/DSU) - answer-A Channel Service Unit/Data Service Unit
(CSU/DSU) is a device that prepares data traffic for digital lines. The DSU converts the digital frames
used in the service provider's network into a frame format that the router can understand and vice
versa. The CSU provides termination for the digital signal and ensures connection integrity through error
correction and line monitoring.
Checksum/CRC - answer-A checksum, also known as a Cyclic Redundancy Check or CRC, is a simple
mathematical calculation performed on each frame to ensure it hasn't been corrupted in transit.
CIDR Block - answer-A CIDR block is a representation of the addresses in a range indicated by the prefix
length in an address specified in CIDR or "slash" notation.
Classful Routing - answer-Classful Routing or Classful IP Addressing was a scheme that divided the IP
address space into different-sized chunks or classes of addresses based on how many octets were used
for the network portion and how many were used for the host number. With classful IP addressing, the
network number always fell on an octet boundary. For example, a Class A network used the first octet
