Next: B The Test Setup
Up: Implementing a High Performance
Most definitions below are taken from .
- Abbreviation for acknowledgement.
- A response sent by the receiver to indicate a
successful reception of information.
- (Address Resolution Protocol) The TCP/IP protocol
used to dynamically bind a high-level IP address to a low-level
- A packet delivery system that delivers a copy of a
given packet to all hosts that attach to the same network.
- A small, integer value computed from a sequence of
bytes by treating them as integers and computing the sum. A checksum
is used to detect errors that result when a sequence of bytes is
transmitted from one machine to another. Typically, protocol
software computes a checksum an appends it to a packet when
transmitting. Upon reception, the protocol software verifies the
contents of the packets by recomputing the checksum and comparing to
the value sent. Many TCP/IP protocols use a 16-bit checksum computed
witch one's complement arithmetic, with all integer fields in the
packet stored in network byte order.
- (Checksum Redundancy Avoidance) A way to eliminate
the checksum calculation if it is possible, e.g. when the packet has
only travelled over a local network.
- (Cyclic Redundancy Check) A small, integer value
computed from a sequence of bytes used to detect errors that result
when the sequence of bytes is transmitted from one machine to
- Flow control
- Control of the rate at which hosts or routers
inject packets into a network or internet, usually to avoid
- Any end-user computer system that connects to a network.
Hosts range in size from personal computers to supercomputers.
- (Internet Control Message Protocol) An integral
part of the Internet Protocol that handles error and control
messages. Specifically routers and hosts use ICMP to send reports of
problems about datagrams back to the original source that sent the
- Physically, a collection of packet switching networks
interconnected by routers along with TCP/IP protocols that allow
them to function logically as a single, large, virtual network. When
written in upper case, Intern refers specifically to the global
- The collection of networks and routers that spans the
world, and uses TCP/IP protocol to form a single, cooperative
- (Internet Protocol) The TCP/IP standard protocol that
defines the IP datagram as the unit of information passed across an
internet and provides the basis for connectionless, best-effort
packet delivery service.
- IP address
- A 32-bit address assigned to each host that
participates in an internet. IP addresses are the abstraction of
physical hardware address just as an internet is an abstraction of
physical networks.To make routing efficient IP addresses are divided
into a network potion and a host portion.
- IP datagram
- The basic unit of information passed across a
TCP/IP internet.An It contains source and destination address along
- (Internet Protocol -the Next Generation) A term
applied to all the activities surrounding the specification and
standardization of the next version of IP, IPv6.
- Used loosely to refer to any small block of data sent
across a packet switching network.
- The abstraction that TCP/IP transport protocols use to
distinguish among multiple destinations within a given host
computer. TCP/IP protocols identify ports using small positive
integers. Usually, the operating system allows an application
program to specify which port it wants to use. Some ports are
reserved for standard services (e.g. electronic mail).
- A formal description of message formats and the rules
two or more machines must follow to exchange those messages.
Protocols can describe low-level details of machine to machine
interfaces, or high-level exchange between application programs.
- Pseudo header
- Source and destination IP address information
sent in the IP header, but included in a TCP or UDP checksum.
- The operation an application performs on a TCP to force
data to be sent immediately. A bit in the segment header marks
- The process of collecting all the fragments of an IP
datagram and using them to create a copy of the original datagram.
The ultimate destination performs reassembly.
- (Request For Comments) The name of a series of notes
that contain surveys, measurements, ideas, techniques, and
observations, as well as proposed and accepted TCP/IP protocol
- In general, a route is the path that network traffic
takes from its source to its destination. In TCP/IP internet, each
IP datagram is routed independently; routes can change dynamically.
- A special purpose, dedicated computer that attaches to
two or more networks and forwards packets from one to the other. A
router uses the destination address on a datagram to choose a
next-hop to which is forwards the datagram.
- The unit of transfer sent from TCP on one machine to
TCP on another. Each segment contains part of a stream of bytes
being sent between the machines as well as additional fields that
identify the current position in the stream and a checksum to ensure
validity of received data.
- Sliding window
- Characteristic of protocols that allow a sender
to transmit more than one packet of data before receiving an
acknowledgement. After receiving an acknowledgement for the first
packet sent, the sender ``slides'' the packet window and sends
another. The number of outstanding packets or bytes is known as the
window size; increasing the widow size improves throughput.
- (SYNchronizing segment) The first segment sent by
the TCP protocol, it is used to synchronize the two ends of a
connection in preparation for opening a connection.
- (Transmission Control Protocol) The TCP/IP standard
transport level protocol that provides the reliable, full duplex,
stream service on which many application protocols depend. TCP
allows a process on one machine to send a stream of data to a
process on another. TCP is connection-oriented in the sense that
before transmitting data, participants must establish a connection.
All data travel in TCP segments, which each travel across the
Internet in an IP datagram. The entire protocol suite is often
referred to as TCP/IP because TCP and IP are the two fundamental
- (User Datagram Protocol) The TCP/IP standard
protocol that allows an application program on one machine to send a
datagram to an application on another. UDP uses Internet Protocol to
deliver datagrams. Conceptually, the important difference between
UDP datagrams and IP datagrams is that UDP includes a protocol port
number, allowing sender to distinguish among multiple application
programs on a given remote machine. In practice, UDP also includes
an optional checksum over the data being sent. UDP use unlike TCP
unreliable data transfer.
Next: B The Test Setup
Up: Implementing a High Performance
Thu Jun 5 00:52:23 MET DST 1997