Installing and Administering HP EISA FDDI/9000 and HP HSC FDDI/9000

105
Glossary
token passing A method where
each node, in turn, receives and
passes on the right to use the
channel. The nodes are usually
configured in a logical ring.
Token Ring A network topology
utilizing a token-passing media
access protocol in a ring topology.
100 Mbps FDDI and ANSI 802.5 4-
and 16-Mbps Token Ring are token
ring technologies.
trace A diagnostic process to
recover from a stuck-beacon
condition. The fault is localized to
the beaconing MAC and its
upstream neighbor MAC.
Transport layer Layer 4 in the
OSI model; defines protocols
governing message structure and
some error checking.
TRT (Token Rotation Timer) A
clock that times the period between
the receipt of tokens.
TTP (Timed-Token Protocol)
The rules defining how the target
token rotation time is set, the length
of time a station can hold the token,
and how the ring is initialized.
TTRT (Target Token Rotation
Time) The value used by the MAC
receiver to time the operations of the
MAC layer. The TTRT value varies,
depending on whether or not the ring
is operational.
TVX (Valid Transmission
Timer) A timer that times the
period between valid transmissions
on the ring; used to detect excessive
ring noise, token loss, and other
faults.
U
upstream A term that refers to the
relative position of two stations in a
ring. A station is upstream of its
neighbor if it receives the token
before its neighbor receives the
token.
UTP (Unshielded Twisted
Pair) Type 3 cable with one or more
twisted pairs where the wiring is not
protected from electromagnetic and
radio frequency, but covered with
plastic or PVC.