Allied Telesis AlliedWare Plus Operating System Version 5.4.4C (x310-26FT,x310-26FP,x310-50FT,x310-50FP) - Manual (Page 2217)

Appendix B: Glossary
Software Reference for x310 Series Switches
C613-50046-01 REV A AlliedWare Plus TM Operating System - Version 5.4.4C B.27
Synchronous
Transmission in which the data characters and bits are transmitted at a fixed rate with the
transmitter and receiver synchronized. This eliminates the need for start-stop elements, as
in asynchronous transmission, but requires a flag character to be transmitted when there
is no data to transmit. See
“Asynchronous” on page B.4
T
TACACS+
TACACS+ (Terminal Access Controller Access-Control System Plus) provides a method for
securely managing multiple network access points from a single management service.
TACACS+ is a TCP-based access control protocol that allows a device to forward a user's
username and password to an authentication server to determine whether access can be
allowed. In addition to this authentication service, TACACS+ can also provide
authorization and accounting services. One of the features of TACACS+ is the ability to
separate authentication, authorization and accounting so that these functions can be
provided independently on separate servers.
For information on the AlliedWare Plus implementation of TACACS+, see Chapter 48,
TACACS+ Introduction and Configuration and Chapter 49, TACACS+ Commands .
TCN
Topology Change Notification.
Thrash limiting
MAC address thrashing occurs when MAC addresses move rapidly between one or more
ports or trunks, for example, due to a network loop. Thrash limiting enables you to apply
actions to a port when thrashing is detected. It is supported on all port types and also on
aggregated ports.
For more information see “Thrash Limiting” on page 14.14
TLV
Type-Length-Value. A single LLDPDU contains multiple TLVs. TLVs are short information
elements that communicate complex data, such as variable length strings, in a
standardized format. Each TLV advertises a single type of information, such as its device ID,
type, or management addresses. See
LLDP advertisements .
Traceroute
Traceroute is used to discover the route that packets pass between two systems running
the IP protocol. Traceroute sends an initial UDP packets with the Time To Live (TTL) field in
the IP header set starting at 1. The TTL field is increased by one for every subsequent
packet sent until the destination is reached. Each hop along the path between two
systems responds with a TTL exceeded packet (ICMP type 11) and from this the path is
determined.