In computer security, the process of ensuring that only authorized users can access the resources of a computer system in authorized ways.
Activation script
A command script that Cisco ANA applies to one or more VNEs to extend their configurations. You use Cisco ANA Command Builder to create activation scripts. The Cisco Video Assurance Management Solution runs an IPTV activation script on its VNEs.
Alarm
An audible or visual signal at a device, such as a display station or printer, that is used to notify the user that a predefined condition exists.
Alarm Thresholding
A mechanism by which Cisco ANA constantly monitors selected soft properties and generates an alarm every time they cross a user-defined threshold or violate a condition. See also Soft Properties.
ANA
Active Network Abstraction. A Cisco resource management solution designed with a fully distributed OSS mediation platform which abstracts the network, its topology and its capabilities from the physical elements.
ANA EventVision
ANA EventVision is a GUI application that serves as a browser for viewing and retrieving detailed information about the different types of system events and tickets that are generated within the Cisco ANA system. Monitoring EventVision helps predict and identify the sources of system problems, which assists in preventing future problems.
ANA Manage
ANA Manage is a GUI tool in Cisco ANA that performs various system administration activities for simple system control.
Active Network Abstraction
See ANA.
ANA NetworkVision
ANA NetworkVision is the primary GUI for Cisco ANA. It is a surveillance tool providing total visibility for multi-vendor, multi-tier, multi-technology networks. It also supports fault and configuration functionality.
ANA NetworkVision supports the creation of multiple network maps to represent specific network views. Views can cover specific network segments, customer networks, or any other mix of network elements desired. Once the maps have been created, they are available for all connecting clients (with support for fine grained access privileges).
ASI
Asynchronous serial interface.
ASR 9000
A Cisco carrier class routing solution that uses the Cisco IOS operating system, and which includes comprehensive network management capabilities, and a comprehensive set of Ethernet and Multiprotocol Label Switching (MPLS) operations, administration, and maintenance (OAM) capabilities. The ASR 9000 supports Cisco Video Monitoring VidMon capabilities.
Authentication
In computer security, (1) verification of the identity of a user or the user's eligibility to access an object; (2) verification that a message has not been altered or corrupted; (3) a process that is used to verify the user of an information system or of protected resources.
Authorization
In computer security, (1) the right granted to a user to communicate with or make use of a computer system; (2) the process of granting a user either complete or restricted access to an object, resource, or function.
Automation
In IBM Tivoli/OMNIbus, the ObjectServer can respond automatically to specified alerts.
Autonomous Virtual Machine
See AVM.
AVM
Autonomous Virtual Machine. Java processes that provide the necessary distribution support platform for executing and monitoring multiple VNEs.
B
back-office
The internal operations of an organization that are not accessible or visible to the general public.
back up
To copy information to another location to ensure against loss of data. Contrast with restore.
C
Carrier Routing System-1
See CRS-1
Cisco 7600
A carrier-class edge router that offers integrated, high-density Ethernet switching, carrier-class Internet Protocol/Multiprotocol Label Switching (IP/MPLS) routing, and 10-Gb/s interfaces.Cisco 7600 ES+ line cards on the Cisco 7600 support VidMon.
Cisco Info Center
Cisco Info Center is a service level management (SLM) system that collects enterprise-wide event information from many different network data sources and presents a simplified view of the event information to operators and administrators. Cisco Info Center is provided with the Cisco VAMS Solution, and includes the Object Server, Netcool Web GUI, Nckl, and Tivoli/Netcool Impact.
Cisco Multicast Manager
A web-based network management application that simplifies the holistic discovery, visualization, monitoring, and troubleshooting of multicast networks. CMM is applicable to multiple system operators that use multicast to transport video over IP.
Configuration
The machines, devices, and programs that make up a system, subsystem, or network.
CPU
Central Processing Unit.
CRC
Cyclic Redundancy Check. Error-checking technique in which the frame recipient calculates a remainder by dividing frame contents by a prime binary divisor and compares the calculated remainder to a value stored in the frame by the sending node.
CRS-1
Carrier Routing System-1. A Cisco large-scale core router for carrier networks.
Cyclic Redundancy Check
See CRC.
D
DCM
See Digital Content Manager.
Deduplication
Deduplication (also known as record linkage) is a task of finding the same (duplicate) entry in multiple files. You use deduplication when merging two or more data sets. Deduplication is a useful tool when performing data mining tasks, where the data originated from different sources or different organizations.
Delay Factor
See DF.
Deploy
To place files or install software into an operational environment.
Designated Router
See DR.
Device
Any non-client, non-server part of a network managed by Tivoli software, including, but not limited to, cable set-top boxes and other pervasive devices.
DF
Delay Factor. A time value indicating the amount of data that buffers must contain to eliminate jitter.
Digital Content Manager
Cisco Digital Content Manager (DCM). A Cisco multiplexing appliance that allows processing of a high number of MPEG video streams and supports advanced MPEG processing functions such as content re-compression to lower bit rates, open loop statistical multiplexing, digital program insertion and scrambling.
Digital Storage Media - Command and Control
See DSM-CC.
Digital Subscriber Line Access Multiplexer
See DSLAM.
Digital Video Broadcast
See DVB.
Discovery
The automatic detection of a topology change, such as finding new and deleted nodes or links within a network topology, or such as finding storage resources and devices within a network that are not yet being monitored.
Domain
A logical grouping of resources in a network for the purpose of common management and administration.
Domain name
In the Internet suite of protocols, a name of a host system. A domain name consists of a sequence of subnames that are separated by a delimiter character. For example, Cisco.com.
DR
Designated Router. A router in a multiaccess network that designates the originate network link advertisements and establishes adjacencies with all routers in the network.
Drools rules engine
Drools rules engine is a general-purpose expert-system generator and combines rule-based techniques and object-oriented programming. It also provides a customizable mechanism to add decision support and data flow control functions to business applications.
Drools rules engine is based on an object-oriented paradigm and uses user-defined rules to perform pattern matching on different conditions. The rules are written in a Java-like syntax, and are organized into source files (known as a rule files), which are plain ASCII files.
DSLAM
Digital Subscriber Line Access Multiplexer. A device that connects many digital subscriber lines to a network by multiplexing the DSL traffic onto one or more network trunk lines.
DSM-CC
Digital Storage Media - Command and Control. A toolkit for developing control channels associated with MPEG-1 and MPEG-2 streams.
DVB
Digital Video Broadcast. A European standard for digital television.
E
EMS
Element Management System. A system that manages a network of elements.
Element Management System
See EMS.
ETR-290
European Telecommunications Standards Institute Technical Report 290 (ETR-290), Digital Video Broadcasting (DVB): Measurement Guidelines for DVB Systems is a report produced by the European Broadcasting Union (EBU) that provides guidelines for measurements of video transmission and quality in DVB satellite, cable and terrestrial and related digital television systems, including Moving Picture Experts Group (MPEG)-2 transmission.
ETR-290 First Priority Alarms
Alarms that indicate that ETSI indicators listed in Table 5.2.1 in the ETR-290 specification—First priority: necessary for de-codability (basic monitoring)—are activated. These indicators indicate that a video transport stream (TS) is not decodable. The ETR-290 First Priority alarms include:
•TS Loss—The first byte of a Transport Stream packet header is the synchronization byte (0x47). A TS Loss error occurs when the synchronization byte in a sequence of at least two Transport Stream packets are not detected.
•CC Error—Indicates a discontinuity error in the MPEG TS structure for a particular video program.
•Sync Byte Error—The synchronization byte in a Transport Stream packet is not detected. A Transport Stream Loss alarm is also triggered.
•PAT Error—Occurs when the PMT reference in the Program Association Table (PAT) for the service is missing. A Service Loss alarm is also triggered.
•PMT Error—Occurs when the Program Map Table (PM) for the service is not available within a particular time interval or contains errors. A Service Loss alarm is also triggered.
•PID Error—A Packet ID (PID) error occurs when components with PMT reference are not found within a particular time interval. A Service Loss alarm is also triggered.
Event
Any significant change in the state of a system resource, network resource, or network application. An event can be generated for a problem, for the resolution of a problem, or for the successful completion of a task.
F
Field
The building block of which objects are composed. A field is characterized by a field name, a data type (integer, Boolean, character string, or enumerated value), and a set of flags that describe how the field is treated. A field can contain data only when it is associated with an object.
G
Gateway
In the IP community, an older term referring to a routing device. Today, the term router is used to describe nodes that perform this function, and gateway refers to a special-purpose device that performs an application layer conversion of information from one protocol stack to another.
H
HDD
Hard disk drive.
Health check
A report that shows the values over time of one or more metrics, which can be selected from one or more schemas, for one or more components. Typically, a health check shows time-delineated, diagnostic data that shows the fluctuation of key indicators.
Heartbeat Monitoring
See IP Multicast Heartbeat Monitoring.
Host
A computer that is connected to a network (such as the Internet or an Systems Network Architecture [SNA] network) and provides an access point to the network. Also, depending on the environment, the host may provide centralized control of the network. The host can be a client, a server, or both a client and a server simultaneously.
HFC
Hybrid Fiber-Coaxial. Technology being developed by the cable TV industry to provide two-way, high-speed data access to the home by using a combination of fiber optics and traditional coaxial cable.
Hybrid Fiber-Coaxial
See HFC.
I
IBM Tivoli Network Services Manager
See TBSM.
iVMS
IP Video Management System (iVMS) from Ineoquest Technologies has been added to CMM 2.5 to provide real-time alerts to allow for rapid fault isolation of customer impacting video events.
ICMP
Internet Control Message Protocol. Network layer Internet protocol that reports errors and provides other information relevant to IP packet processing. Documented in RFC 792.
IGMP
Internet Group Management Protocol. Used by IP hosts to report their multicast group memberships to an adjacent multicast router.
Impact
A component of the Cisco Info Center application, IBM/Tivoli Netcool/Impact provides a common platform for data access that circumvents organizational boundaries. In the Cisco VAMS environment, Netcool/Impact collects data from devices and applications used in the video headend and video transport network and correlates the data into events that are tailored to the IP Multicast video processing environment.
Internet Control Message Protocol
See ICMP.
Internet Group Management Protocol
See IGMP.
Internet Protocol Television
See IPT.
Internet Service Monitors
See ISM.
IP Multicast Heartbeat Monitoring
Cisco routers can monitor the data plane of a multicast group and detect when that group is no longer receiving multicast packets. When the configured threshold for a heartbeat has been exceeded, the router sends an SNMP trap, which Cisco Info Center receives. This is useful to confirm that the traffic stream is active. From Tivoli Business Service Manager, you can monitor heartbeat events to confirm that the routers and switches are receiving the monitored multicast video flows.
IPTV
Internet Protocol Television. Video transport over IP.
IPTV extensions
Configurations that extend the capabilities of the VNEs to include functions that are unique to the Cisco Video Assurance Management Solution. These extensions are applied to supported VNEs with an activation script.
IP Video Management System
See iVMS.
IRD
Integrated receiver/decoder.
ISM
Internet Service Monitors. A collection of software components that monitors the status and performance of Internet services such as e-mail, Dynamic Host Configuration Protocol (DHCP), Domain Name Service (DNS), and Remote Authentication Dial-In User Service (RADIUS). To assist CIC users in integrating CIC with ISM, CIC includes utilities you can run after installing CIC and ISM. These utilities customize the ISM installation to function more smoothly with CIC.
J
Java EventLists
See JEL.
JEL
Java EventLists. Java EventLists use passive software probes to collect network events from a wide variety of management environments. Then, JEL distributes color-coded views (output from the Netcool/OMNIbus ObjectServer memory-resident SQL data repository) of networked services to operators who monitor service levels. When combined, the topology displays and Java EventLists are updated in real time, giving managers a collaborative network management environment.
M
Management Information Base
See MIB.
Map
A named collection of objects, symbols, submaps, and their relationships, all of which represent the network topology. See topology.
MDI:MLR
Media Delivery Index:Media Loss Rate. A video metric that measures: (1) Magnitude of lost MPEG frames and (2) Per MPEG PID loss using Continuity Counter field
MDI:MLR is derived by summarizing the total missing MPEG frames for a given reporting period for a given PID (program
MDI:MRV
Media Delivery Index:Media Loss Rate. A video metric that measures (1) Magnitude of lost MPEG frames (2) Per MPEG PID loss using Continuity Counter field.
MDI:MLR is derived by summarizing the total missing MPEG frames for a given reporting period for a given program ID (PID).
MDT
Multicast Distribution Tree. A distribution tree that controls the path that IP multicast traffic takes through the network to deliver traffic to all receivers. The two basic types of multicast distribution trees are source trees and shared trees.
Media Delivery Index
See MDI:MLR.
Media Loss Rate
See MLR.
Media Rate Variation
See MRV.
MIB
Management Information Base. Network management protocol, such as SNMP, uses and maintains a database of network management information. The value of a MIB object can be changed or retrieved by using SNMP commands, usually through a GUI network management system.
MLR
Media Loss Rate. The number of lost or out-of-order media packets per second.
Motion Picture Experts Group
See MPEG.
MPEG
Motion Picture Experts Group. Standard for compressing video. MPEG1 is a bit stream standard for compressed video and audio optimized to fit into a bandwidth of 1.5 Mb/s. Intended for higher quality video-on-demand applications, MPEG2 runs at data rates between 4 and 9 Mb/s. Intended for 64-kb/s connections, MPEG4 is a low-bit-rate compression algorithm.
MPLS
Multiprotocol Label Switching. Switching method that forwards IP traffic by using a label. This label instructs the routers and the switches in the network where to forward the packets based on preestablished IP routing information.
MTTrapd probe
The Cisco MTTrapd (Multi-Threaded) probe is the main probe used with Cisco Info Center in the Cisco VAMS environment. The MTTrapd probe monitors SNMP traps and events on both UDP and TCP sockets.
MUXId
Multiplex ID. A table that describes video channels transmitted in multicast video flows.
MVPN
Multicast VPN.
Multicast Distribution Tree
See MDT.
Multicast VPN
See MVPN.
Multiprotocol Label Switching
See MPLS.
N
NE
Network Element. A user-named physical component or device existing in the network.
Netcool Knowledge Library
Also known as NcKL, IBM Netcool Knowledge Library is a collection of rules files that are tuned to specific managed objects that send SNMP-based events, such as Cisco networking devices. These rules support a wide range of Cisco system MIBs, including MIBs for specific Cisco devices, protocols, and technologies, as well as syslog messages from a wide range of Cisco devices.
Network Element
See NE.
Network Time Protocol
See NTP.
NTP
Network Time Protocol. Protocol built on top of TCP that ensures accurate local time-keeping with reference to radio and atomic clocks located on the Internet. This protocol is capable of synchronizing distributed clocks in milliseconds over long time periods.
O
Object Identifier
See OID.
Object Server
The Object Server is the database server at the core of Cisco Info Center, where all events are stored and managed. The Object Server consolidates events such as faults, alarms, and warning messages collected by probes from various management environments. The in-memory database is optimized to handle large volumes of events, which is essential for networks where thousands of events may arrive each second.
OID
Object Identifier. Values are defined in specific MIB modules. The Event MIB allows a user or an NMS to watch over specified objects and to set event triggers based on existence, threshold, and boolean tests. An event occurs when a trigger is fired; this means that a specified test on an object returns a value of true. To create a trigger, a user or an NMS configures a trigger entry in the mteTriggerTable of the Event MIB. This trigger entry specifies the OID of the object to be watched. For each trigger entry type, corresponding tables (existence, threshold, and boolean tables) are populated with the information required for carrying out the test. The MIB can be configured so that when triggers are activated (fired) either an SNMP Set is performed, a notification is sent out to the interested host, or both.
Operations Support Systems/Business Support Systems
See OSS/BSS.
OSS/BSS
Operations Support Systems/Business Support Systems. Operations support systems (OSS) and business support systems are a set of programs that help a communications service provider monitor, control, analyze, and manage a telephone or computer network.
P
Packet ID
See PID.
Packets per second
See PPS.
PAT
Program Association Table. A table that lists the PIDs that are associated with the PMTs in the transport stream.
PCR
Program Clock Reference. A clock reference on a program PID that helps to present programs on time and at the right speed.
PE
Provider Edge. A router at the edge of a network service provider area.
PID
Packet ID. The ID of a packet in a transport stream.
PIM
Protocol Independent Multicast. Multicast routing architecture that allows the addition of IP multicast routing on existing IP networks. PIM is a unicast routing protocol which is independent and can be operated in two modes: dense and sparse.
PMT
Program Map Table. A table that provides information about a program on a video transport stream. The PMT lists the PIDs of the streams associated with the program.
Polling
(1) The process whereby stations are invited, one at a time, to transmit. The polling process usually involves the sequential interrogation of several data stations. (2) In network management, the process by which a manager interrogates one or more managed nodes at regular intervals. (3) The process by which databases are interrogated at regular intervals to determine if data needs to be transmitted.
PPS
Packets per second.
Presentation Time Stamp
See PTS.
Probe
In the Cisco Info Center architecture, a probe is an application that acquires data from network devices and forwards it to the Object Server. A probe is a are non-intrusive software listeners that identifies and collects SNMP MIB and non-SNMP events and data. See Mttrapd probe.
Program Association Table
See PAT.
Program Clock Reference
See PCR.
Program Map Table
See PMT.
Protocol Independent Multicast
See PIM.
Provider Edge
See PE.
Provision
To provide, deploy, and track a service or component.
Provisioning
The process of setting up and maintaining a user's access to a system.
PTS
Presentation Time Stamp. The time stamp when a video or audio frame must be presented to the user.
Q
QAM
Quadratrue Amplitude Modulation. Method for encoding digital data in an analog signal in which each combination of phase and amplitude represents one of sixteen four-bit patterns. Also refers to devices that encode digital cable channels for transmission over cable.
Quadrature Amplitude Modulation
See QAM.
QoS
Quality of Service. Measure of performance for a transmission system that reflects its transmission quality and service availability.
Quality of Service
See QoS.
R
RDBMS
Relational Database Management System. A collection of hardware and software that organizes and provides access to a relational database.
Realtime Transport Protocol
See RTP.
Registry
The data store that contains access and configuration information for users, systems, and software.
Relational database
A database that can be perceived as a set of tables and manipulated in accordance with the relational model of data.
Relational database management system
See RDBMS.
Rendezvous Point
See RP.
Reverse Path Forwarding
See RPF.
Root-cause analysis
The process of determining the actual cause of a network problem. For example, when a device on a network cannot be reached, it might be because of a problem with the device or a problem with a network component that is used to reach that device.
ROSA EMS
The ROSA EMS is a hardware and software platform that allows network operators to monitor the video headend using a web browser client. The ROSA EMS:
- Polls the devices that it manages and reports any problems that occur as SNMP alarms.
- If configured to perform backup protection, automatically indicates predefined backup schemes that reroute signals and activate and configure standby devices within seconds of a device failure.
- Can pass alarms to the ROSA NMS.
ROSA NMS
A Cisco network management system for video that runs on dedicated hardware platform with preloaded ROSA NMS software or as a client application that runs on Microsoft Windows 2000, Microsoft Windows XP, Microsoft Windows Vista, or Microsoft Windows Server 2003 and communicates with the ROSA NMS Server.
The ROSA NMS manages Telco, CATV, HFC networks, Multichannel Multipoint Distribution System (MMDS) sites, satellite uplinks, and broadcast stations in accordance with basic telecom network management principle. In the Cisco VAMS Solution, the ROSA NMS sends SNMP traps to Cisco Info Center, which are viewable using TBSM.
RP
Rendezvous Point. Router specified in PIM sparse mode implementations to track membership in multicast groups and to forward messages to known multicast group addresses.
RPF
Reverse Path Forwarding. Multicasting technique in which a multicast datagram is forwarded out of all but the receiving interface if the receiving interface is the one used to forward unicast datagrams to the source of the multicast datagram. Non-RPF packets, also called RPF failure packets, are RPF packets that have been transmitted backwards, against the flow from the source.
RTP
Realtime Transport Protocol. IP transport protocol that provides media-specific time stamp data for real-time flows.
Rule
A set of logical statements that enable the event server to recognize relationships among events and to execute automated responses accordingly. See also event.
Run time
The time period during which a computer program is executing. A run-time environment is an execution environment.
S
Schema
The set of statements, expressed in a data definition language, that completely describe the structure of a database. In a relational database, the schema defines the tables, the fields in each table, and the relationships between fields and tables.
SDI
Serial digital interface.
Secure sockets layer
See SSL.
Service provider
Any company that provides services for a fee to its customers, such as telecommunication companies, application service providers, enterprise IT, and Internet service providers (ISPs). These fee services include application provisioning, application hosting, service level agreement management, and others.
Service Dashboard
The VAMS Service Dashboard provides a view of services in the video network that includes a Service Tree showing a hierarchical view of the services, a Service Viewer that shows a topology map of the devices involved in the selected service, and an event list for the service.
Service Details window
The area of the VAMS Service Dashboard that shows a detailed event list for the service.
Service Tree
The area of the VAMS Service Dashboard that shows a hierarchical tree diagram of the video services in the network.
Service Viewer
The area of the VAMS Service Dashboard that shows a topology view of the selected service.
Set-top box
See STB.
SHE
Super Head End. Network location for live feeds for the broadcast video service. This site contains the real-time encoders used for the broadcast video service, along with the asset distribution systems for on-demand services. This site may also contain back-office systems such as the subscriber database. The SHE typically resides in the core of the transport network.
Simple Network Management Protocol
See SNMP.
SNMP
Simple Network Management Protocol. Network management protocol used almost exclusively in TCP/IP networks. SNMP provides a means to monitor and control network devices, and to manage configurations, statistics collection, performance, and security.
Soft Properties
Cisco ANA offers the soft properties mechanism to enable user-configurable extensions of device modeling, which can cover any unsupported MIB variable. This mechanism enables adding new monitored NE properties in runtime to the default set of supported properties.
Every soft property is implemented through a set of definitions that determine how to retrieve, parse and display a certain MIB variable from the NE. The definition process is done through a simple GUI utility, and does not require system restart. Soft properties are retrieved from the NE by using SNMP, or Telnet/SSH.
See also Alarm Thresholding.
SSL
Secure sockets layer. A security protocol that provides communication privacy. SSL enables client/server applications to communicate in a way that is designed to prevent eavesdropping, tampering, and message forgery.
STB
Set-top box. A set-top box (STB) or set-top unit (STU) is a device that connects to a television and an external source of signal, turning the signal into content which is then displayed on the television screen.
Structured Query Language
See SQL.
SQL
Structured Query Language. A database computer language designed for the retrieval and management of data in relational database management systems (RDBMS), database schema creation and modification, and database object access control management.
SQL is a standard interactive and programming language for querying and modifying data and managing databases. Although SQL is both an ANSI and an ISO standard, many database products support SQL with proprietary extensions to the standard language. The core of SQL is formed by a command language that allows the retrieval, insertion, updating, and deletion of data, and performing management and administrative functions.
Super Head End
See SHE.
T
TBSM
IBM Tivoli Business and Services Manager (TBSM) is an application that integrates the Cisco Info Center product with the IBM Tivoli/Netcool network management application and allows Tivoli to manage a Cisco Info Center installation. TBSM provides a service dashboard and visualization tool that you can use to view service trees for multicast video networks and view events sent to by TBSM the components of the Cisco VAMS Solution.
TCA
Threshold Crossing Alert. A system message that alerts the operator when a provisionable threshold has been crossed.
Threshold
A customizable value for defining the acceptable tolerance limits (maximum, minimum, or reference limit) for an application resource or system resource. When the measured value of the resource is greater than the maximum value, less than the minimum value, or equal to the reference value, an exception is raised.
Threshold Crossing Alert
See TCA.
TIP
The high-level interface for Cisco Video Assurance Management Solution 3.1 is the Tivoli Integrated Portal (TIP) and the Tivoli Business Service Manager (TBSM). TIP allows you to launch TBSM and customized event views for events in the video headend and video transport network.
Tivoli Integrated Portal
See TIP.
Topology
Physical arrangement of network nodes and media within an enterprise networking structure.
Transrating
See Video Rate Shaping.
V
VHO
Video Hub Office. Network location of the video server complex, which includes the video sources for on-demand services and real-time encoders for local television stations. A VHO typically serves a metropolitan area of between 100,000 and 1,000,000 homes.
Video Hub Office
See VHO.
Video Rate Shaping
Video rate shaping, also known as transrating, is a process that converts video to a constant bit rate while also reducing the video bit rate.
Video Switching Office
See VSO.
Virtual Network Element
See VNE.
Virtual Private Network
See VPN.
VNE
Virtual Network Element. A virtual representation of a single network element as a modeled component. VNEs all communicate with each other to present ANA-based applications with a single, common device abstraction for network element discovery, configuration, status collection, fault analysis and other basic network functions. VNEs can be extended to support new application functionality.
VPN
Virtual Private Network. Enables IP traffic to travel securely over a public TCP/IP network by encrypting all traffic from one network to another. A VPN uses tunneling to encrypt all information at the IP level.
VPN routing/forwarding
See VRF.
VRF
VPN routing/forwarding. A VRF consists of an IP routing table, a derived forwarding table, a set of interfaces that use the forwarding table, and a set of rules and routing protocols that determine what goes into the forwarding table.
VSO
Video Switching Office. VSOs house aggregation routers that aggregate traffic from subscriber homes.
Z
ZAP
Zone Announcement Protocol. A multicast protocol for discovering the multicast administrative scope zones that are relevant at a particular location. See RFC 2776.
Feedback
TS Loss—The first byte of a Transport Stream packet header is the synchronization byte (0x47). A TS Loss error occurs when the synchronization byte in a sequence of at least two Transport Stream packets are not detected.