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YML781 Rev1 NB1 Quick Start Guide
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Filtering To screen out selected types of data, based on filtering
rules. Filtering can be applied in one direction (upstream
or down stream), or in both directions.
filtering rule A rule that specifies what kinds of data a routing device
will accept and/or reject. Filtering rules are defined to
operate on an interface (or multiple interfaces) and in a
particular direction (upstream, downstream, or both).
Firewall Any method of protecting a computer or LAN connected
to the Internet from intrusion or attack from the outside.
Some firewall protection can be provided by packet filter-
ing and Network Address Translation services.
FTP File Transfer Protocol - A program used to transfer files
between computers connected to the Internet. Common
uses include uploading new or updated files to a web
server, and downloading files from a web server.
GGP Gateway to Gateway Protocol. An Internet protocol that
specifies how gateway routers communicate with each
other.
Gbps Abbreviation for Gigabits (GIG-uh-bits) per second, or
one billion bits per second. Internet data rates are often
expressed in Gbps.
GRE Generic Routing Encapsulation. TCP/IP protocol suite,
transport layer encapsulation protocol.
hop When you send data through the Internet, it is sent first
from your computer to a router, and then from one router
to another until it finally reaches a router that is directly
connected to the recipient. Each individual “leg” of the
data’s journey is called a hop.
hop count The number of hops that data has taken on its route to its
destination. Alternatively, the maximum number of hops
that a packet is allowed to take before being discarded ,
See also TTL.
host A device (usually a computer) connected to a network.
HTTP Hyper-Text Transfer Protocol HTTP is the main protocol
used to transfer data from web sites so that it can be
displayed by web browsers. See also web browser
ICMP Internet Control Message Protocol An Internet protocol
used to report errors and other network-related informa-
tion. The ping command makes use of ICMP.
IGMP Internet Group Management Protocol An Internet protocol
that enables a computer to share information about its
membership in multicast groups with adjacent routers.
A multicast group of computers is one whose members
have designated as interested in receiving specific con-
tent from the others. Multicasting to an IGMP group can
be used to simultaneously update the address books of
a group of mobile computer users or to send company
newsletters to a distribution list.