Cisco Systems Cisco IOS XR manual GL-12

Glossary

TACACS	Terminal Access Controller Access Control System. Authentication protocol, developed by the DDN
	community, that provides remote access authentication and related services, such as event logging.
	User passwords are administered in a central database rather than in individual routers, providing an
	easily scalable network security solution.

tar

target configuration

task ID

Tbps

TCP

Telnet

A tar file is a file produced by the UNIX tar program, which packages multiple files in a single file for distribution as a single unit. Each tar file has a tar filename extension.

A “two-stage” configuration of the Cisco IOS XR software running configuration. This allows users to make changes to the running configuration and accept these changes by entering the commit command.

An identifier that determines user access to a given command or series of commands. A user must be a member of a group with the appropriate task IDs assigned to it to execute the related commands.

terabits per second. The amount of data that can be sent in a fixed amount of time. 1 terabit = 240 bits, or 1,099,511,627,776 bits.

Transmission Control Protocol. Connection-oriented transport layer protocol that provides reliable full-duplex data transmission. TCP is part of the TCP/IP protocol stack.

Standard terminal emulation protocol in the TCP/IP protocol stack. Telnet is used for remote terminal connection, enabling users to log in to remote systems and use resources as if they were connected to a local system. Telnet is defined in RFC 854.

terabyte	A unit of computer memory or data storage capacity equal to 1024 gigabytes (240 bytes).
	Approximately 1 trillion bytes.
TFTP	Trivial File Transfer Protocol. A simplified version of FTP that allows files to be transferred from one
	computer to another over a network, usually without the use of client authentication (for example,
	username and password).
	Note: some TFTP servers (such as Sun Solaris) may not support file sizes larger that 32 MB.
trap	Message sent by an SNMP agent to an NMS, a console, or a terminal to indicate the occurrence of a
	significant event, such as a specifically defined condition or a threshold that was reached.
tunnel	Secure communication path between two peers, such as two routers.
Tx	The transmitter end of a fabric link. All links are unidirectional. See also Rx.

U

UDP		User Datagram Protocol. Connectionless transport layer protocol in the TCP/IP protocol stack. UDP is
		a simple protocol that exchanges datagrams without acknowledgments or guaranteed delivery,
		requiring that error processing and retransmission be handled by other protocols. UDP is defined in
		RFC 768.
unicast		Message sent to a single network destination.
unicast		A unicast transmission sends one copy of each packet to each member of the group. This method is
transmission		inefficient because the same information must be carried multiple times, requiring extra bandwidth.
		Cisco IOS XR Getting Started Guide
	GL-12	OL-10957-02