Cloned from: CCNA Vocabulary



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Enterprise Network
Network that integrates all systems within a company or organization. An enterprise network differs from a WAN because it is privately owned and maintained.
Converged Network
A network capable of carrying voice, video and digital data.
NOC
An enterprise centralizes network management in a Network Operations Center.
Failover
Occurrence of a redundant network device performing the load or function of another device automatically if the initial device fails. The failover scheme creates a backup system for mission-critical hardware and software. The objective is to reduce the impact of system failure to a minimum by actively monitoring and identifying system failure.
Mission-critical
Type of network or computing process that is vital to an organization. Mission-critical applications that are halted often or for too long may have negative consequences.
Hierarchical Design Model
Representation of a network featuring an access layer, a distribution layer, and core layer.
Access Layer
Level of the hierarchical Cisco internetworking model that encompass the hosts that are the point of entry into the network. Access Layer devices include switches, hubs, workstations, servers, IP phones, web cameras, and access points.
Distribution Layer
Layer in a hierarchical design between the Access layer and Core layer. The Distribution layer interconnects access layer hosts and switches, and provides security and traffic management for the Core Layer.
Core Layer
Layer in a three-layer hierarchical design with the Access Layer and Distribution Layer. The Core Layer is a high-speed backbone layer between geographically dispersed end networks.
ECNM
Enterprise Composite Network Model Cisco network design that divides the network into functional components while still maintaining the concept of Core, Distribution, and Access layers. The functional components are the Enterprise Campus, Enterprise Edge, and Service Provider Edge.
Enterprise Campus
Consists of the campus infrastructure with: Building Access, Building Distribution, Campus Core, Server Farms, and Network Management
Enterprise Edge
Consists of the Internet, VPN, and WAN modules connecting the enterprise with the service provider's network The module extends the enterprise services to remote sites and enables the enterprise to use Internet and partner resources. It provides QoS, policy enforcement, service levels, and security
Service Provider Edge
Provides Internet, Public Switched Telephone Network (PSTN), and WAN services
Edge device
Filter on the perimeter of an enterprise network where incoming packets are passed. Examples of edge devices include firewall and DMZ. Edge devices may be equipped with IDS and IPS to examine and block unwanted traffic.
IDS
Intrusion Detection System Combination of a sensor, console, and central engine in a single device installed on a network to protect against attacks missed by a conventional firewall. IDS inspects all inbound and outbound network activity and identifies suspicious patterns that may indicate a network or system attack. It is configured to send an alarm to network administrators when such attack is encountered.
IPS
Intrusion Prevention System Active device in the traffic path that monitors network traffic and permits or denies flows and packets into the network. All traffic passes through an IPS for inspection. When the IPS detects malicious traffic, it sends an alert to the management station and blocks the malicious traffic immediately. IPS proactively prevents attacks by blocking the original and subsequent malicious traffic.
DMZ
Demilitarized Zone Area in a network design that is located between the internal network and external network, usually the Internet. The DMZ is accessible to devices on the Internet, such as a web server, FTP server, SMTP server, and DNS.
Failure Domain
Area of a network that is affected when a networking device malfunctions or fails. A properly designed network minimizes the size of failure domains.
Downtime
Percentage of time in which a network is unavailable because of administrative shutdown or equipment failure.
Back end
Application that performs final or hidden functions in a process.
POP
Point of Presence Physical connection between a communication facility provided by an ISP or local telephone company , and an organization’s main distribution facility.
HDLC
High-Level Data Link Control Bit-oriented synchronous Data Link Layer protocol developed by ISO. HDLC specifies a data encapsulation method on synchronous serial links using frame characters and checksums.
PPP
Point-to-point Protocol Standard that provides router-to-router and host-to-network connections over synchronous and asynchronous circuits.
Frame Relay
Industry-standard, switched, WAN standard that operates at the Physical Layer and Data Link Layer of the OSI Reference Model. Frame Relay handles multiple virtual circuits using HDLC encapsulation between connected devices. It is more efficient than the X.25 protocol that it replaced.
ATM
Asynchronous transfer mode International standard for the cell relay of service types, such as voice, video, or data. In ATM, the services are conveyed in fixed-length, 53-byte cells. Fixed-length cells reduce transit delays because cell processing occurs in the hardware. ATM is designed for high-speed transmission media such as E3, SONET, and T3.
Intranet
Networks accessible internal users of an organization. An intranet is used to share internal information and computing resources
Extranet
Network that provides access to information or operations of an organization to suppliers, vendors, partners, customers, or other businesses. Extranet is a private network using Internet protocols and the public telecommunication system to share internal resources. It may be considered an extension of an intranet.
External Traffic
Data communication to and from a private network. External Traffic is traffic that originates from or is destined to the Internet. VPN and Internet traffic is considered external traffic flow.
Packet Sniffer
Tool that analyzes traffic flows based on the source and destination of the traffic as well as the type of traffic being sent. Packet sniffer analysis can be used to make decisions on how to manage the traffic more efficiently.
UDP
User Datagram Protocol Standard for connectionless transmission of voice and video traffic. Transmissions using UDP are not affected by the delays caused from acknowledgements and retransmitting lost packets.
TCP
Transmission Control Protocol
TCP provides services that ensure accurate and timely delivery of network communications between two hosts. TCP provides the following services to ensure message delivery:
· Sequencing of data packets · Flow control · Error checking While the use of acknowledgements makes TCP a more reliable delivery protocol, it also incurs a delay.
Latency
1) Delay between the time when a device receives a frame and the time that frame is forwarded out the destination port. 2) Data latency is the time between a query and the results displaying on the screen.
Jitter
Analog communication line distortion. Jitter can be caused by the variation of a signal from the reference timing positions, network congestion, or route changes. It can cause data loss, particularly at high speeds.
QoS
Quality of Service Standard for monitoring and maintaining a level of transmission performance and service, such as available data transmission bandwidth and error rate.
Teleworking
Employee that works at a location other than the centralized office location.
Telecommuting
Working from a location other than the centralized office
Teleworker
Employee that works at a location other than the centralized office
Teleconferencing
Method for a group of people to communicate in real time online
VoIP
Voice Over Internet Protocol Standard for transmitting voice data encapsulated in an IP packet on an already implemented IP network without needing its own network infrastructure. In VoIP, the digital signal processor divides the voice signal into frames which are paired in groups of two and stored in voice packets. The voice packets are transported using IP in compliance with ITU-T specification H.323.
FTP
File Transfer Protocol
20 & 21 TCP
FTP provides a generic method of transferring files. It can include file security through usernames and passwords, and it allows file transfer between dissimilar computer systems. FTP can transfer both binary and text files, including HTML, to another host. FTP URLs are preceded by ftp:// followed by the DNS name of the FTP server. To log in to an FTP server, use: ftp://username@servername. Uses ports 20 & 21. Port 20 it the port the FTP server opens to send information back to the FTP client. 21 is the actual port that all FTP servers bind to by default. Defined in RFC959.
Telnet
Remote Terminal Emulation
Telnet allows an attached computer to act as a dumb terminal, with data processing taking place on the TCP/IP host computer. It is still widely used to provide connectivity between dissimilar systems. Telnet can also be used to test a service by the use of HTTP commands.
Uses port 23 TCP
VPN
Virtual Private Network Network through which data is sent through a public telecommunication infrastructure while maintaining the privacy of the data by creating a tunnel through the public telecommunication infrastructure.
TLS
Transport Layer Security
TLS ensures that messages being transmitted on the Internet are private and tamper proof. TLS is implemented through two protocols: •TLS Record--Can provide connection security with encryption (with DES for example).
•TLS Handshake--Provides mutual authentication and choice of encryption
method.
IPSec
IP Security A suite of protocols that provide many services including:
  • ·         Data encryption
  • ·         Integrity validation
  • ·         Peer authentication
  • ·         Key management
IPSec provides security services at the IP layer. IPSec uses IKE to handle the negotiation of protocols and algorithms based on local policy and to generate the encryption and authentication keys to be used by IPSec. IPSec can protect one or more data flows between a pair of hosts, between a pair of security gateways, or between a security gateway and a host.
Network Infrastructure Diagram
Illustration of the topology of a network that shows the location, function, and status of devices. A network infrastructure diagram may represent either a physical or logical network.
Topology
Map of the arrangement of network nodes and media within an enterprise networking infrastructure. Topology can be physical or logical.
Physical Topology
Layout of devices on a network. The physical topology shows the way that the devices are connected through the cabling and how cables are arranged.
Logical Topology
Map of the flow of data on a network that shows how devices communicate with each other.
Control Plane
Collection of processes that run at the process level on the route processor. Control plane processes collectively provide high-level control for most Cisco IOS functions. Control plane information describes failure domains and defines the interfaces where different network technologies intersect.
CSU/DSU
Channel service unit/data service unit Network devices that connect an organization to a digital circuit.
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