Copyright © 2004-2005, Vivato, Inc.
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into ERP and the IEEE
standard is a scheme for effective interoperability of IEEE 802.11g stations
with IEEE 802.11b nodes on the same channel.
Legacy IEEE 802.11b devices cannot detect the ERP-OFDM signals used by IEEE 802.11g stations, and
this can result in collisions between data frames from IEEE 802.11b and IEEE 802.11g stations.
If there is a mix of 802.11b and 802.11g nodes on the same channel, the IEEE 802.11g stations detect this
via an ERP flag on the AP/Bridge and enable
request to send
(
) and
clear to send
(
) protection
before sending data.
See also
protocol.
Frame
A
Frame
consists of a discrete portion of data along with some descriptive meta-information packaged for
transmission on a wireless network. Each frame includes a source and destination
address, a control
field with protocol version, frame type, frame sequence number, frame body (with the actual information to
be transmitted) and frame check sequence for error detection. A Frame is similar in concept to a
the difference being that a packet operates on the Network layer (layer 3 in the OSI model) whereas a
frame operates on the Data-Link layer (layer 2 in the OSI model).
Gateway
A
gateway
is a network node that serves as an entrance to another network. A gateway also often provides
a proxy server and a firewall. It is associated with both a router, which use headers and forwarding tables
to determine where packets are sent, and a switch or bridge, which provides the actual path for the packet
in and out of the gateway.
Before a host on a
can access the Internet, it needs to know the address of its
default gateway
.
HTML
The
Hypertext Markup Language
) defines the structure of a document on the World Wide Web. It
uses tags and attributes to hint about a layout for the document.
An HTML document starts with an
<html>
tag and ends with a
</html>
tag. A properly formatted
document also contains a
<head>
...
</head>
section, which contains the metadata to define the
document, and a
<body>
...
</body>
section, which contains its content. Its markup is derived from the
Standard Generalized Markup Language
(SGML), which is defined in
HTML documents are sent from server to browser via
HTTP
The
Hypertext Transfer Protocol
) defines how messages are formatted and transmitted on the
World Wide Web. An HTTP message consists of a
and a command (
GET
,
HEAD
,
POST
, etc.), a request
followed by a response.
IAPP
The
Inter AP/Bridge Protocol
(IAPP) is an
standard (
) that defines communication between
the AP/Bridges in a "distribution system". This includes the exchange of information about mobile stations
and the maintenance of bridge forwarding tables, plus securing the communications between AP/Bridges.