Net Tech Prefi

Encapsulation

A process where new information is added to an existing unit to form a new unit.

Decapsulation

The reverse process of encapsulation, where headers and tails are removed to obtain the data payload.

Data payload

The actual information that is intended to be transmitted.

Packet

A data unit exchanged and transmitted on a network, consisting of header, data payload, and tail.

Header

Information segment added before the data payload during packet assembly for transmission.

Tail

Information segment added after the data payload to facilitate information transmission.

Protocol Data Unit (PDU)

A specific block of information transferred over a network; describes different types of data at each OSI layer.

Physical layer PDU

Raw bits (1s and 0s) transmitted physically via hardware.

Data Link layer PDU

A frame, which is a series of bits.

Network layer PDU

A packet that contains the source and destination address.

Transport layer PDU

A segment that includes a TCP header and data.

Session layer PDU

Data passed to the network connection.

Presentation layer PDU

Data formatted for presentation.

Application layer PDU

Data received or transmitted by a software application.

Internet Protocol (IP)

Defines a packet, an addressing scheme, and routes packets to remote hosts.

Internet Control Message Protocol (ICMP)

Handles errors and controls the process of sending data between computers.

Internet Group Management Protocol (IGMP)

Handles multicasting; keeps routers informed of hosts' membership in multicast groups.

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 permanent storage to find its Internet address from its physical address.

Ethernet

A family of LANs defined by IEEE 802.3 standards using a CSMA/CD access method.

Point-to-Point Protocol (PPP)

Protocol used for data transfer across a serial line.

Fiber Distributed Data Interface (FDDI)

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 for various data types.

Frame Relay

A WAN protocol for fast and efficient LAN internetworking.

Proxy ARP

Used by a terminal to pass data between segments without changing its IP address.

Routing

The process of selecting paths on a network for sending packets from source to destination.

Path determination

Enables a router to select the best route based on destination address and routing table.

Routes

Path information used to guide packet forwarding.

Routing device (Router)

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

Packet routing

The overall process of finding the most efficient path for IP packets.

Routing table

A database with information about which port to use to send packets to specific network segments.

Destination

Identifies a destination subnet in routing.

Mask

Identifies a subnet along with a destination IP address.

Outbound interface

Interface through which data packets are sent out of the router.

Next hop

The address used by the router to forward packets to the destination subnet.

Packet Forwarding

Moving information between interfaces according to routing directions.

Packet Delivery

How a packet is handled by underlying physical networks.

Direct Delivery

occurs when an IP node forwards a packet to its final destination.

Indirect Delivery

occurs when an IP node forwards a packet to an intermediate router.

Routing Table (Huawei)

A database containing information about routes to network segments.

Preference (Pre)

Indicates the routing protocol preference of a route.

Cost

The metric that indicates the cost of a route.

Route Preference

Logic by which routers choose optimal routes based on preference values.

Direct routes

Automatically generated routes pointing to directly connected networks.

Static routes

Manually configured routes by network administrators for simple structures.

Dynamic routes

Learned via dynamic routing protocols, enabling routers to communicate about networks.

Routing

The process of selecting the best path for packet forwarding.

Router

A device that forwards packets between networks based on routing information.