Appliance Trim Kit User Manual

Appendix A: Glossary
103
statistics Every Blue Coat appliance keeps statistics of the appliance hardware and the objects
it stores. You can review the general summary, the volume, resources allocated, cache
efficiency, cached contents, and custom URLs generated by the appliance for various
kinds of logs. You can also check the event viewer for every event that occurred since
the appliance booted.
stream A flow of a single type of data, measured in kilobits per second (Kbps). A stream
could be the sound track to a music video, for example.
SurfControl log type A proprietary log type that is compatible with the SurfControl reporter tool. The
SurfControl log format includes fully-qualified usernames when an NTLM realm
provides authentication. The simple name is used for all other realm types.
syslog An event-monitoring scheme that is especially popular in Unix environments. Most
clients using Syslog have multiple devices sending messages to a single Syslog
daemon. This allows viewing a single chronological event log of all of the devices
assigned to the Syslog daemon. The Syslog format is: “Date Time Hostname Event.”
system cache The software cache on the appliance. When you clear the cache, all objects in the
cache are set to expired. The objects are not immediately removed from memory or
disk, but a subsequent request for any object requested is retrieved from the origin
content server before it is served.
T
time-to-live (TTL) value Used in any situation where an expiration time is needed. For example, you do not
want authentication to last beyond the current session and also want a failed
command to time out instead of hanging the box forever.
traffic flow
(bandwidth gain)
Also referred to as flow. A set of packets belonging to the same TCP/UDP connection
that terminate at, originate at, or flow through the SG appliance. A single request
from a client involves two separate connections. One of them is from the client to the
SG appliance, and the other is from the SG
appliance to the OCS. Within each of
these connections, traffic flows in two directions—in one direction, packets flow out
of the SG appliance
(outbound traffic), and in the other direction, packets flow into
the SG (inbound traffic). Connections can come from the client or the server. Thus,
traffic can be classified into one of four types:
•Server inbound
• Server outbound
•Client inbound
• Client outbound
These four traffic flows represent each of the four combinations described above.
Each flow represents a single direction from a single connection.
transmission control
protocol (TCP)
TCP, when used in conjunction with IP (Internet Protocol) enables users to send data,
in the form of message units called packets, between computers over the Internet.
TCP is responsible for tracking and handling, and reassembly of the packets; IP is
responsible for packet delivery.
transparent proxy
A configuration in which traffic is redirected to the SG
appliance without the
knowledge of the client browser. No configuration is required on the browser, but
network configuration, such as an L4 switch or a WCCP-compliant router, is
required.