Extreme Networks ExtremeWare XOS Guide Manual page 654

Glossary
I (Continued)
IGMP snooping
IGP
inline power
IP
IPv6
IP address
ExtremeWare XOS 11.3 Concepts Guide
This provides a method for intelligently forwarding multicast packets
within a Layer 2 broadcast domain. By "snooping" the IGMP
registration information, the device forms a distribution list that
determines which endstations receive packets with a specific multicast
address. Layer 2 switches listen for IGMP messages and build
mapping tables and associated forwarding filters. IGMP snooping also
reduces IGMP protocol traffic.
Interior Gateway Protocol. IGP refers to any protocol used to exchange
routing information within an AS. Examples of Internet IGPs include
RIP and OSPF.
According to IEEE 802.3 af, inline power refers to providing an AC or
DC power source through the same cable as the data travels. It allows
phones and network devices to be placed in locations that are not near
AC outlets. Most standard telephones use inline power.
Internet Protocol. The communications protocol underlying the
Internet, IP allows large, geographically diverse networks of
computers to communicate with each other quickly and economically
over a variety of physical links; it is part of the TCP/IP suite of
protocols. IP is the Layer 3, or network layer, protocol that contains
addressing and control information that allows packets to be routed.
IP is the most widely used networking protocol; it supports the idea of
unique addresses for each computer on the network. IP is a
connectionless, best-effort protocol; TCP reassembles the data after
transmission. IP specifies the format and addressing scheme for each
packet.
Internet Protocol version 6. IPv6 is the next-generation IP protocol.
The specification was completed in 1997 by IETF. IPv6 is backward-
compatible with and is designed to fix the shortcomings of IPv4, such
as data security and maximum number of user addresses. IPv6
increases the address space from 32 to 128 bits, providing for an
unlimited (for all intents and purposes) number of networks and
systems; IPv6 is expected to slowly replace IPv4, with the two existing
side by side for many years.
IP address is a 32-bit number that identifies each unique sender or
receiver of information that is sent in packets; it is written as four
octets separated by periods (dotted-decimal format). An IP address
has two parts: the identifier of a particular network and an identifier
of the particular device (which can be a server or a workstation)
within that network. You may add an optional subnetwork identifier.
Only the network part of the address is looked at between the routers
that move packets from one point to another along the network.
Although you can have a static IP address, many IP addresses are
assigned dynamically from a pool. Many corporate networks and
online services economize on the number of IP addresses they use by
sharing a pool of IP addresses among a large number of users. (The
format of the IP address is slightly changed in IPv6.)
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