REVIEWER FOR NET TECH

Encapsulation

The process of adding a new string of information to an existing unit to form a new unit of information.

Decapsulation

The reverse process of encapsulation where the header and tail of a packet are removed to obtain the data payload.

Packet

A data unit that is exchanged and transmitted on a network.

Header

The information segment added before the data payload during packet assembly to facilitate information transmission.

Tail

The information segment added after the payload to facilitate information transmission.

Protocol Data Unit (PDU)

A specific block of information transferred over a network.

Internet Protocol (IP)

Defines a packet and an addressing scheme, transferring data between the Internet and network access layers and routing packets to remote hosts.

Internet Control Message Protocol (ICMP)

A TCP/IP protocol that handles errors and controls data transmission between computers.

Internet Group Management Protocol (IGMP)

A TCP/IP protocol that handles multicasting.

Address Resolution Protocol (ARP)

Obtains the physical address of a node from a specific IP number.

Reverse Address Resolution Protocol (RARP)

Allows a host with no local permanent data storage to find its Internet address given its physical address.

Ethernet

A family of LANs using a CSMA/CD access method, being a best-effort delivery system.

Point-to-Point Protocol (PPP)

The protocol used for data transfer across a serial line.

Fiber Distributed Data Interface (FDDI)

A set of ANSI protocols for sending digital data over fiber optic cable.

Asynchronous Transfer Mode (ATM)

A wide area protocol featuring high data rates and equal-sized packets/cells.

Frame Relay

A WAN protocol for LAN internetworking that transmits data across multiple switches and routers.

Proxy ARP

Used when a terminal needs to pass data from one segment to another without changing its current IP address.

Routing

The process of selecting paths on a network along which packets are sent from a source to a destination.

Path Determination

Enables a router to compare the destination address to the available routes and select the best path.

Routes

The path information used to guide packet forwarding.

Router

A network device that forwards packets to a destination subnet based on routes.

Packet Routing

The overall process of finding the most efficient path for forwarding an IP packet from source to destination.

Packet Forwarding

The passing or moving of information between interfaces according to routing directions.

Direct Delivery

Occurs when the IP node forwards a packet to its final destination in the network.

Indirect Delivery

Occurs when the IP node forwards a packet to an intermediate node because the final destination is not directly attached.

Routing Table

A database containing information about which router interface to use to send data to a network segment.

Route Preference

The measure used to compare routes from different protocols with lower values indicating higher preference.

Direct Route

Automatically generated routes that point to directly connected networks.

Static Route

Routes manually configured by administrators suited for small/simple networks.

Dynamic Route

Routes learned by routing protocols and reflecting changing network topologies.