Extreme Networks ExtremeWare XOS Guide Manual page 666

Glossary
S (Continued)
superloop
system health check
T
TACACS+
tagged VLAN
TCN
TCP
TFTP
transit node
U
UDP
ExtremeWare XOS 11.3 Concepts Guide
In EAPS, a superloop occurs if the common link betwee two EAPS
domains goes down and the master nodes of both domains enter the
falied state putting their respective secondary ports into the
forwarding state. If there is a data VLAN spanning both EAPS
domains, this action forms a loop between the EAPS domains.
The primary responsibility of the system health checker is to monitor
and poll error registers. In addition, the system health checker can be
enabled to periodically send diagnostic packets. System health check
errors are reported to the syslog.
Terminal Access Controller Access Control System. Often run on UNIX
systems, the TACAS+ protocol provides access control for routers,
network access servers, and other networked computing devices via
one or more centralized servers. TACACS+ provides separate
authentication, authorization, and accounting services. User passwords
are administered in a central database rather than in individual
routers, providing easily scalable network security solutions.
You identify packets as belonging to the same tagged VLAN by
putting a value into the 12-bit (4 octet) VLAN ID field that is part of
the IEEE 802.1Q field of the header. Using this 12-bit field, you can
configure up to 4096 individual VLAN addresses (usually some are
reserved for system VLANs such as management and default VLANs);
these tagged VLANs can exist across multiple devices. The tagged
VLAN can be associated with both tagged and untagged ports.
Topology change notification. The TCN is a timer used in RSTP that
signals a change in the topology of the network.
Transmission Control Protocol. Together with Internet Protocol (IP),
TCP is one of the core protocols underlying the Internet. The two
protocols are usually referred to as a group, by the term TCP/IP. TCP
provides a reliable connection, which means that each end of the
session is guaranteed to receive all of the data transmitted by the other
end of the connection, in the same order that it was originally
transmitted without receiving duplicates.
Trivial File Transfer Protocol. TFTP is an Internet utility used to
transfer files, which does not provide security or directory listing. It
relies on UDP.
In EAPS, the transit node is a switch, or node, that is not designated a
master in the EAPS domain ring.
User Datagram Protocol. This is an efficient but unreliable,
connectionless protocol that is layered over IP (as is TCP). Application
programs must supplement the protocol to provide error processing
and retransmitting data. UDP is an OSI Layer 4 protocol.
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