Nomadix AG 5000 User Manual page 273

AG 5000
OSPF
(Open Shortest Path First) This routing protocol was developed for IP networks based on the shortest path
first or link-state algorithm. Routers use link-state algorithms to send routing information to all nodes on a
network by calculating the shortest path to each node based on a topography of the Internet constructed by
each node. Routers send that portion of the routing table (keeping track of routes to particular network
destinations) that describes the state of its own links, and it also sends the complete routing structure
(topography). The advantage of shortest path first algorithms is that they result in smaller more frequent
updates everywhere. They converge quickly, thus preventing such problems as routing loops and count-to-
infinity (when routers continuously increment the hop count to a particular network). This makes for a
stable network. OSPF (version 2) is defined in RFC 1583 and is rapidly replacing RIP on the Internet as the
preferred routing protocol. See also,
Packet
How data is distributed over the Internet. A packet contains the source and destination addresses, as well as
the data. An ethernet packet is normally 1,518 bytes. In IP networks, packets are often called datagrams.
See also, Forwarding Rate,
Packet Switching Network
Refers to protocols in which messages are divided into packets before they are sent. Each packet is then
transmitted individually and can even follow different routes to its destination. Once all the packets
forming a message arrive at its destination, they are recompiled into the original message. Most modern
Wide Area Network (WAN) protocols, including TCP/IP, X.25, and Frame Relay, are based on packet-
switching technologies. By contrast, normal telephone services use a circuit-switching technology in which
a dedicated line is allocated for transmission between two parties. Circuit-switching is ideal for fast data
transmissions where the data must arrive in the same order in which it is sent. This is the case with most
real-time data, such as live audio and video. Packet switching is more efficient and robust for data that can
withstand some delays in transmission, such as e-mail messages and Web pages. See also,
Rate, Packet, pps, and Throughput.
PDF
(Portable Document Format) A type of file format developed by Adobe Systems© that displays documents
identically on any computer system. PDF files retain their original formatted design, unlike
documents which adjust the format depending on the users viewing medium (for example, monitor size).
Ping
(Packet INternet Groper) A program that transmits a signal to a host and expects a response within a
predetermined time. This is useful when troubleshooting network transmission problems. See also, ICMP.
Portal
A portal is a Web site. The portal consists of a collection of links to the most popular Web services on the
Internet. Generally speaking, a portal is a door to the Internet. See also, Internet.
PPP
(Point-to-Point Protocol) PPP has superseded SLIP as the standard protocol for serial data communications
over the Internet. See also, SLIP.
pps
(packets per second) The rate at which packets are delivered to their destination. See also,
Rate, Packet, and Packet Switching
Glossary of Terms
RFC and Router.
Packet Switching Network, pps, and Throughput.
Network.
Forwarding
HTML
Forwarding
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