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toll network
WAN network that uses the Public Switched Telephone Net-
work (PSTN) to send packets.
IP command used to trace the path a packet takes through an
traffic shaping
Used on Frame Relay networks to provide priorities of data.
transparent bridging
The bridging scheme used in Ethernet and IEEE
802.3 networks, it passes frames along one hop at a time, using bridging
information stored in tables that associate end-node MAC addresses within
bridge ports. This type of bridging is considered transparent because the
source node does not know it has been bridged, because the destination
frames are sent directly to the end node. Contrast with: SRB.
Transport layer
Layer 4 of the OSI reference model, used for reliable com-
munication between end nodes over the network. The Transport layer pro-
vides mechanisms used for establishing, maintaining, and terminating virtual
circuits, transport fault detection and recovery, and controlling the flow of
information. See also: Application layer, Data Link layer, Network layer,
Physical layer, Presentation layer,
and Session layer.
Token Ring Interface Processor: A high-speed interface processor
used on Cisco 7000 series routers. The TRIP provides two or four ports for
interconnection with IEEE 802.5 and IBM media with ports set to speeds of
either 4Mbps or 16Mbps set independently of each other.
trunk link
Link used between switches and from some servers to the
switches. Trunk links carry information about many VLANs. Access links
are used to connect host devices to a switch and carry only VLAN informa-
tion that the device is a member of.
Time To Live: A field in an IP header, indicating the length of time a
packet is valid.
Trunk Up-Down: A protocol used in ATM networks for the moni-
toring of trunks. Should a trunk miss a given number of test messages being
sent by ATM switches to ensure trunk line quality, TUD declares the trunk
down. When a trunk reverses direction and comes back up, TUD recognizes
that the trunk is up and returns the trunk to service.
Copyright ©2001 SYBEX , Inc., Alameda, CA