Glossary

BANDWIDTH
The amount of data passing through a connection over a given time. It is usually measured in bps (bits-per-second) or Mbps (Megabits per Second). As a general rule, get as much as you can afford – and the make sure you are getting it.

BANDWIDTH SATURATION
The point in which all-available bandwidth on an internet connection is used up.

CONTENT FILTERING
On the internet, content filtering (also known as information filtering) is the use of a program to screen and exclude from access or availability web pages or e-mail that are deemed objectionable. Content filtering is used by corporations and governments as part of internet firewall computers and also by home computer owners, especially by parents to screen the content their children have access to from a computer.

DROPPED PACKETS
Packets (i.e. small data “packages”) are occasionally dropped, or lost, on the network for various reasons. For instance, two nodes may be communicating at widely disparate transfer rates. TCP packets are resent, UDP s are not.

HOP
In a packet-switching network, a hop is the trip a data packet takes from one router or intermediate point to another in the network. On the Internet (or a network that uses TCP/IP), the number of hops a packet has taken toward its destination (called the “hop count”) is kept in the packet header.

ICMP (Internet Control Message Protocol)
Internet Control Message Protocol is a message control and error-reporting protocol between a host server and a gateway to the internet. ICMP uses Internet Protocol (IP) datagrams, but the messages are processed by the IP software and are not directly apparent to the application user.

ISP (Internet Service Provider)
An ISP (aka Carrier, aka Provider) is a company that collects a monthly or yearly fee in exchange for providing the subscriber with internet access.

JITTER
The difference in latency from one packet to the next measured in milliseconds.

LAN (Local Area Network)
A LAN is a computer network that spans a relatively small area. Most LANs are confined to a single building or group of buildings. However, one LAN can be connected to other LANs over any distance via telephone lines and radio waves. A system of LANs connected in this way is called a wide-area network (WAN).

LATENCY
In a network, latency, a synonym for delay, is an expression of how much time it takes for a packet of data to get from one designated point to another. Typically, latency is measured by sending a packet that is returned to the sender. The round-trip time – measured in milliseconds – is considered the latency.

PING
Loosely, ping means “to get the attention of” or “to check for the presence of” another party online. Ping operates by sending a packet to a designated address and waiting for a response. The computer acronym (for Packet Internet or Inter-Network Groper) was contrived to match the submariners’ term for the sound of a returned sonar pulse.

POINT TO POINT
Point-to-point telecommunications generally refers to a connection restricted to two endpoints, usually host computers.

PSTN (Public Switched Telephone Network)
PSTN is the world’s collection of interconnected voice-oriented public telephone networks, both commercial and government-owned.

QOS (Quality of Service)
Describes the ability of a e.g. router to prioritize certain packets.

SIP (Session Initiation Protocol)
SIP is an application-layer control (signaling) protocol for creating, modifying, and terminating sessions with one or more participants. It can be used to create two-party, multiparty, or multicast sessions that include Internet telephone calls, multimedia distribution, and multimedia conferences.

VPN (Virtual Private Network)
VPN is a private network that uses a public network (usually the Internet) to connect remote sites or users together. VPNs use “virtual” connections routed through the Internet from a company’s private network , a remote site or employee.