Preface : Terminology

This section provides definitions for Media Flow Controller terms and industry-standard terms that may be unfamiliar to the reader.
Absolute URL
An absolute URL points to the exact location of a file or directory on the Internet, by name. Contrast with Relative URL.
Assured Flow Rate. A Media Flow Controller option that, when enabled, ensures that media content is delivered at a rate that is minimally needed for the video to play smoothly.
Address Resolution Protocol; allows systems to map IP addresses to MAC addresses.
A data rate (the amount of data transferred in one direction over a link divided by the time taken to transfer it) expressed in bits per second. Juniper Networks notation examples: Kbps (kilobits per second), KB/s (kilobytes per second). See also Profile (Bit-rate profile).
A type of network routing scheme where data is sent to all possible destinations on a network. Contrast with Multicast and Unicast.
Content Delivery Network. A system of computers networked together across the Internet that cooperate transparently to deliver content most often for the purpose of improving performance, scalability, and cost efficiency, to end users.
Computed Historical Datapoints; traffic samples that have been computed in some manner, such as summation and averaging.
Command Line Interface.
Node or software program (front-end device) that requests services from a server.
Central Management Console, Juniper Networks management interface that allows you to push configurations to a number of Media Flow Controllers from a central interface. In Release 2.0.2, only client configuration is supported.
Dynamic Host Configuration Protocol.
Direct Server Return. A method of handling TCP traffic in the context of utilizing a proxy.
Edge cache
An appliance, placed between the Internet and close to the end user, that caches and delivers content (like Java Script, CSS, images, etc.) freeing up Web servers for other processes. Media Flow Controller as an edge cache is effectively a “reverse proxy,” that provides these benefits: reduces the load (network and CPU) on an origin server by servicing previously retrieved content and enhances the user experience due to a decrease in latency.
Flash Media Server.
Full Download
An HTTP media delivery mode in which the entire media file is downloaded before playback; contrast with Progressive Download (PDL).
Hard Disk Drives.
“Hot” Content (Short Tail vs. Long Tail)
When content is often requested it becomes “hot.” Media Flow Controller caches content hierarchically based on hotness. Short tail videos are those that are often requested: a few videos requested by many different clients. Long tail videos are those that are seldom requested: many different videos requested by few clients.
Data placed on a Media Flow Controller, analyzed, and queued; contrast with Pre-stage.
KB and KiB
KB=1000 Kilo Bytes (networking), KiB=1024 Kilo Bytes (storage).
Local boot
This refers to booting from the default boot partition on the system, i.e. when the reboot command is given.
MB, MiB, and Mbit
MB=1,000,000 Mega Bytes (networking). MiB=1,048,576 (1024 x 1024) Mega Bytes (storage). Mbit=1,000,000 x 8 Megabits (data transfer).
Maximum transmission unit. The size (in bytes) of the largest packet or frame that a given layer of a communications protocol can pass onwards.
A type of network routing scheme where data is sent to certain destinations based on address. Contrast with Broadcast, and Unicast.
A defined collection of delivery policies for different categories of content or domains.
NFS (network file system)
A protocol that allows a user on a client computer to access files over a network similarly to how local storage is accessed.
Network Interface Controller/Card.
Network Time Protocol.
Origin library
The source of media content, typically a server located at a data center.
Origin server
The media content server. Juniper Networks Media Flow Controller can be configured as an Origin server.
Player (media player software)
Any media player for playing back digital video data from files of appropriate formats such as MPEG, AVI, RealVideo, Flash, QuickTime, and so forth. In addition to VCR-like functions such as playing, pausing, stopping, rewinding, and forwarding, some common functions include zooming/full screen, audio channel selection, subtitle selection, and frame capturing.
Data placed on a Media Flow Controller or origin server before an HTTP request comes in for it. Contrast with Ingest.
Profile (Bit-rate profile)
A media “bit-rate profile” is the bit-rate encoding that allows optimal downloads to different bandwidths.
Progressive Download (PDL)
An HTTP media delivery mode in which the media file is played while it is being downloaded; contrast with Full Download.
Proxy (reverse, mid-tier, transparent, virtual)
A reverse proxy is a server processing in-bound traffic, installed in front of origin servers. Reverse proxies are used for scaling origin servers, caching (serving commonly-accessed files), load balancing, and security (denying requests, preventing direct origin server access, etc.). A mid-tier proxy sits between the origin servers and the edge, and serves requests from the edge caches. Mid-tier proxies improve response time for requests because content is closer to the user; and off-load origin servers from repeat requests from the edge. A transparent proxy is a proxy that does not modify the request or response beyond what is required for proxy authentication and identification. Transparent proxies help optimize networks transparently (no client configuration required, no modification of traffic done). A virtual proxy uses the HOST header of the incoming request to derive origin; use this variant of a reverse proxy as an alternate to providing a single origin-server. Media Flow Controller can be used in any of these capacities.
Publishing Point (live-pub-point)
A way to distribute content to your users (live or broadcast as live); either through a defined SDP (service delivery protocol) file, or a namespace.
Pull vs. Push
Pull refers to media fetches from the origin server initiated by Media Flow Controller based on received requests. Push refers to scheduled media deliveries from the origin server to Media Flow Controller.
PXE (Preboot eXecution Environment) boot
A way to boot computers using a network interface without needing a CDROM or USB drive; PXE must be properly installed first.
Remote Authentication Dial In User Service. A networking protocol that provides centralized access, authorization and accounting management for people or computers to connect and use a network service.
Relative URL
A relative URL points to the location of a file from a point of reference, usually the directory beneath. Preceded by two dots (../directory_path/file.txt) for the directory above; one dot (./directory_path/file.txt) for the current directory. Contrast with Absolute URL.
Real Time Messaging Protocol. A multimedia streaming and RPC (remote procedure call) protocol primarily used in Adobe Flash. RTMP has three variations: The “plain” protocol which works on top of TCP and uses port 1935, RTMPT which is encapsulated within HTTP requests to traverse firewalls, RTMPS which works just like RTMPT but over a secure HTTPS connection.
Real-time Transport Protocol. A standardized packet format for delivering audio and video over the Internet. It is used in conjunction with other protocols such as RTSP. The RTP standard defines a pair of protocols, RTP and the Real-time Transport Control Protocol (RTCP). RTP is used for transfer of multimedia data and RTCP is used to periodically send control information and QoS (quality of service) parameters between the server and client.
Real Time Streaming Protocol. An application level protocol for the control of real-time streaming data sent over RTP. Typically RTP data is sent over UDP, but it can also be sent over the RTSP channel via an interleaved mechanism or over TCP via port 80 with HTTP-like syntax and operations.
RU (Rack Unit)
A unit of measurement of the height of a rack-mounted device.
A communications abbreviation for “receive.”
Serial attached SCSI. A data transfer technology designed to move data to and from computer storage devices such as hard drives and tape drives.
Serial Advanced Technology Attachment. A computer bus technology primarily designed for transfer of data to and from a hard disk.
Solid-state drive, a storage device using solid-state memory to store persistent data.
Streaming is the process of playing a file while it is still being downloaded. Streaming technology lets a user view and hear digitized content as it is being downloaded.
When a payload protocol is incompatible with the delivery network, a tunneling protocol can encapsulate it for delivery only; no polices can be applied.
A type of network routing scheme where data is sent to a single destination host on a network. Contrast with Broadcast, and Multicast.
Uniform Object Locator, Uniform Resource Identifier, Uniform Resource Locator (respectively).
This namespace argument refines what requests Media Flow Controller accepts. In the URL shown below, the uri-prefix could be defined as / (slash), /vod, or /vod/path1. If / (slash) is used, all incoming requests to that domain are honored; if /vod, only requests containing “/vod” (and any sub-directory of it) are honored; if /vod/path1, requests must include that prefix and that sub-directory (sub-sub-directories of path1 need not be specified).
Virtual Host
A virtual host is a capability of some computers that can respond to different IP addresses and offer different services appearing to be a distinct host on a distinct machine; a single machine can supply several virtual hosts.
Virtual Player
This is a Media Flow Controller term referring to the sever-side player provided by Media Flow Controller to assist in media viewing. Media Flow Controller offers several types of virtual player for use in different scenarios; for SmoothFlow, the Type 4 virtual player is used exclusively.
Video On Demand.

Report an Error
Media Flow Controller Administrator's Guide and CLI Command Reference
Copyright © 2010 Juniper Networks, Inc.