User's Manual

User’s Manual of SGS-5240 Series Managed Switch
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Fast Leave
IGMP snooping Fast Leave processing allows the switch to remove an interface from the forwarding-table entry without
first sending out group specific queries to the interface. The VLAN interface is pruned from the multicast tree for the
multicast group specified in the original leave message. Fast-leave processing ensures optimal bandwidth
management for all hosts on a switched network, even when multiple multicast groups are in use simultaneously.
H
HTTP
HTTP is an acronym for Hypertext Transfer Protocol. It is a protocol that used to transfer or convey information on the
World Wide Web (WWW).
HTTP defines how messages are formatted and transmitted, and what actions Web servers and browsers should
take in response to various commands. For example, when you enter a URL in your browser, this actually sends
an HTTP command to the Web server directing it to fetch and transmit the requested web page. The other main
standard that controls how the World Wide Web works is HTML, which covers how web pages are formatted and
displayed.
Any Web server machine contains, in addition to the web page files it can serve, an HTTP daemon, a program that
is designed to wait for HTTP requests and handle them when they arrive. The Web browser is an HTTP client,
sending requests to server machines. An HTTP client initiates a request by establishing a Transmission Control
Protocol (TCP) connection to a particular port on a remote host (port 80 by default). An HTTP server listening on
that port waits for the client to send a request message.
HTTPS
HTTPS is an acronym for Hypertext Transfer Protocol over Secure Socket Layer. It is used to indicate a secure HTTP
connection.
HTTPS provide authentication and encrypted communication and is widely used on the World Wide Web for
security-sensitive communication such as payment transactions and corporate logons.
HTTPS is really just the use of Netscape's Secure Socket Layer (SSL) as a sublayer under its regular HTTP
application layering. (HTTPS uses port 443 instead of HTTP port 80 in its interactions with the lower layer, TCP/IP.)
SSL uses a 40-bit key size for the RC4 stream encryption algorithm, which is considered an adequate degree of
encryption for commercial exchange.
I
ICMP
ICMP is an acronym for Internet Control Message Protocol. It is a protocol that generated the error response,
diagnostic or routing purposes. ICMP messages generally contain information about routing difficulties or simple
exchanges such as time-stamp or echo transactions. For example, the PING command uses ICMP to test an Internet
connection.
IEEE 802.1X
IEEE 802.1X is an IEEE standard for port-based Network Access Control. It provides authentication to devices
attached to a LAN port, establishing a point-to-point connection or preventing access from that port if authentication
fails. With 802.1X, access to all switch ports can be centrally controlled from a server, which means that authorized
users can use the same credentials for authentication from any point within the network.
IGMP
IGMP is an acronym for Internet Group Management Protocol. It is a communications protocol used to manage the
membership of Internet Protocol multicast groups. IGMP is used by IP hosts and adjacent multicast routers to establish
multicast group memberships. It is an integral part of the IP multicast specification, like ICMP for unicast connections.
IGMP can be used for online video and gaming, and allows more efficient use of resources when supporting these
uses.