Ericsson HL950 Administrator's Manual page 158

Multi Service Edge Device HL950
Administrator's Guide
SYN Flooding
Typically most systems process a queue of about 10 connections attempts (SYNs) at a time. A
malicious intruder who fabricates connection attempts and tries to "flood" a system is using a denial of
service attack known as SYN flooding.
T
T1
Similar to the European E1, T1 is the North American format for digital transmission. T1 lines are
popular leased line option for business connecting to the Internet and for ISPs connecting to the
Internet backbone. T1 lines are sometimes referred to as DS1 lines.
TCP – Transmission Control Protocol
TCP is one of the main protocols in TCP/IP networks. Whereas the IP protocol deals only with
packets, TCP enables two hosts to establish a connection and exchange streams of data. TCP
guarantees delivery of data and also guarantees that packets will be delivered in the same order in
which they were sent.
TDM – Time Division Multiplexing
TDMoIP – TDM over IP
TIF – Telephony Interface Module
Traffic shaping
Is a process of minimizing the congestion of a stream of traffic at every connection, physical or
virtual. The net effect is to optimize the overall result.
U
UBR – Unspecified Bit Rate
A type of ATM service that does not guarantee any throughput levels. This is used for applications,
such as file transfer, that can tolerate delays.
UDP – User Datagram Protocol
UDP is a connectionless protocol that, like TCP, runs on top of IP networks. Unlike TCP/IP, UDP/IP
provides very few error recovery services, offering instead a direct way to send and receive datagrams
over an IP network. It's used primarily for broadcasting messages over a network.
UDT – Unstructured Data Transfer
An AAL1 convergence sub layer procedure where all payload and framing bits of an emulated circuit
are carried on an ATM VC.
V
VBR – Variable Bit Rate
A type of ATM service that provides a specified throughput capacity but is not sent evenly. This is a
popular choice for voice and videoconferencing data.
VBRNRT – Variable Bit Rate Non Real Time
VBRRT – Variable Bit Rate Real Time
EN/LZT 108 5995 R3 Page 158 (159)
June 2003