IP: Internet Protocol. The lowest layer protocol defined in TCP/IP. This is the base layer on which all other protocols mentioned herein are built. IP is often referred to as TCP/IP as well.

UDP: User Datagram Protocol. This is a connectionless protocol built on top of IP. It does not provide any guarantees on the ordering or delivery of messages. This protocol is layered on top of IP. Known as younger brother of TCP

TCP: Transmission Control Protocol. TCP is a connection oriented protocol that guarantees that messages are delivered in the order in which they were sent and that all messages are delivered. If a TCP connection cannot deliver a message it closes the connection and informs the entity that created it. This protocol is layered on top
of IP.

ICMP: Internet Control Message Protocol. ICMP is used for diagnostics in the network. The Unix program, ping, uses ICMP messages to detect the status of other hosts in the net. ICMP messages can either be queries (in the case of ping) or error reports, such as when a network is unreachable.

RFC: Request For Comment. RFCs are documents that define the protocols used in the IP Internet. Some are only suggestions, some are even jokes, and others are published standards. Several sites in the Internet store RFCs and make them available for anonymous ftp.

SLIP: Serial Line IP. An implementation of IP for use over a serial link (modem). CSLIP is an optimized (compressed) version of SLIP that gives better throughput.

Bandwidth: The amount of data that can be pushed through a link in unit time. Usually measured in bits or bytes per second.

Latency: The amount of time that a message spends in a network going from point A to point B.

Jitter: The effect seen when latency is not a constant. That is, if messages experience a different latencies between two points in a network.

RPC: Remote Procedure Call. RPC is a method of making network access to resource transparent to the application programmer by supplying a "stub" routine that is called in the same way as a regular procedure call. The stub actually performs the call across the network to another computer.

Marshalling: The process of taking arbitrary data (characters, integers, structures) and packing them up for transmission across a network.

MBONE: A virtual network that is a Multicast backbone. It is still a research prototype, but it extends through most of the core of the Internet (including North America, Europe, and Australia). It uses IP Multicasting which is defined in RFC-1112. An MBONE FAQ is available via anonymous ftp from: ftp.isi.edu" There are frequent broadcasts of multimedia programs (audio and low bandwidth video) over the MBONE. Though the MBONE is used for mutlicasting, the long haul parts of the MBONE use point-to-point connections through unicast tunnels to connect the various multicast networks worldwide.

So till next time, bye.