Blue Coat Systems Blue Coat Systems SG Appliance, SGOS Version 5.2.2 manual Appendix A: Glossary

Appendix A: Glossary

non-cacheable objects	A number of objects are not cached by the Blue Coat appliance because they are
	considered non-cacheable. You can add or delete the kinds of objects that the
	appliance considers non-cacheable. Some of the non-cacheable request types are:
	• Pragma no-cache, requests that specify non-cached objects, such as when you click
		refresh in the Web browser.
	•	Password provided, requests that include a client password.
	•	Data in request that include additional client data.
	•	Not a GET request.
.nsc file	Created from the multicast station definition and saved through the browser as a text
	file encoded in a Microsoft proprietary format. Without an .nsc file, the multicast
	station definition does not work.
NTP	To manage objects in an appliance, an SG appliance must know the current Universal
	Time Coordinates (UTC) time. By default, the SG appliance attempts to connect to a
	Network Time Protocol (NTP) server to acquire the UTC time. SG appliance includes
	a list of NTP servers available on the Internet, and attempts to connect to them in the
	order they appear in the NTP server list on the NTP tab.
O
object (used in caching)	An object is the item that is stored in an appliance. These objects can be frequently
	accessed content, content that has been placed there by content publishers, or Web
	pages, among other things.

object (used in Visual Policy Manager)

An object (sometimes referred to as a condition) is any collection or combination of entry types you can create individually (user, group, IP address/subnet, and attribute). To be included in an object, an item must already be created as an individual entry.

object pipelining	This patented algorithm opens as many simultaneous TCP connections as the origin
	server will allow and retrieves objects in parallel. The objects are then delivered from
	the appliance straight to the user's desktop as fast as the browser can request them.
origin content server (OCS)	Also called origin server. This is the original source of the content that is being
	requested. An appliance needs the OCS to acquire data the first time, to check that
	the content being served is still fresh, and to authenticate users.
outbound traffic (bandwidth	Network packets flowing out of the SG appliance. Outbound traffic mainly consists
gain)	of the following:
	•	Client outbound: Packets sent to the client in response to a Web request.
	•	Server outbound: Packets sent to an OCS or upstream proxy to request a service.
P
PAC (Proxy	Originally created by Netscape, PACs are a way to avoid requiring proxy hosts and
AutoConfiguration) scripts	port numbers to be entered for every protocol. You need only enter the URL. A PAC
	can be created with the needed information and the local browser can be directed to
	the PAC for information about proxy hosts and port numbers.
packet capture (PCAP)	Allows filtering on various attributes of the Ethernet frame to limit the amount of
	data collected. You can capture packets of Ethernet frames going into or leaving an
	SG appliance.

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