Juniper MEDIA FLOW CONTROLLER 2.0.4 -, Руководство администратора

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How Media Flow Controller Works 43
Media Flow Controller Administrator’s Guide Media Flow Controller Overview
Email and Email2SMS Alerts
Media Flow Controller allows you to be notified via email during events such as high CPU/
Memory utilization, Interface up/down, threshold crossing on statistics or counters. Media Flow
Controller uses SMTP protocol to send emails to the administrators. You can use the
Email2SMS facility provided by mobile network operators to configure Media Flow Controller
to send SMS notifications.
Example:
From: "System Administrator" <do-not-reply@mfc.example.com>
Date: December 28, 2009 9:40:47 AM PST
To: admin@example.com
Subject: System event on mfc.example.com: Process exit: ftpd
Hostname: mfc.example.com
Date: 2009/12/28 17:40:47
Description: Unexpected exit of process ftpd.
Uptime: 1h 15m 34.860s
Version: mfc-1.2.0
How Media Flow Controller Works
A single Media Flow Controller can sustain up to 40,000 simultaneous connections for
different media streams and operate in three different proxy modes: reverse proxy,
transparent proxy, and mid-tier proxy. Media Flow Controller consolidates all streaming
protocols (HTTP, RTSP, RTMP) into a single server, reducing the number of servers required
to deliver video over multiple protocols.
Media Flow Controller is able to get content from origin servers or origin storages once, and
serve it to several users simultaneously.
When a request for content is received, Media Flow Controller identifies the content to be
served, and does a resource check to verify that the content can be delivered in an acceptable
manner for that session. After the delivery session is admitted, AssuredFlow can guarantee
certain resources throughout the life of that session: if Media Flow Controller does not have
enough resources, it rejects the request.
Media Flow Controller then checks its hierarchical caches to minimize the cost of serving this
media object. If no copy exists in any cache (also known as “cache miss”), Media Flow
Controller posts a request to the target origin server, fetches the content, and serves it to the
user. Then Media Flow Controller decides if that content is cache-worthy. Media Flow
Controller decides the cache-worthiness based on its intelligent Analytical Engine and
customer-configured policies. When objects become “hot” (downloaded at a high rate), Media
Flow Controller promotes them to a cache tier that supports faster delivery. Promotion in
Media Flow Controller can happen starting from the lowest tier; for example, SATA to SAS,
SSD, and RAM. This allows Media Flow Controller to scale throughput and meet increased
demand.
The Analytical Engine determines the “hotness” of content based on frequency of download
requests. As requests for a particular video increase, the hotness of that video increases and
the Analytical Engine moves that video up in the cache hierarchy. Likewise, as requests for a
video fall off, the Analytical Engine moves that video down in the cache hierarchy.