Cisco 10000 - Manual (Page 526)

Glossary
GL-10
Cisco 10000 Series Router Software Configuration Guide
OL-2226-23
T
ToS Type of service. First defined in RFC 791.
trap Message sent by an SNMP agent to a network management station, console, or terminal to indicate the
occurrence of a significant event, such as a specifically defined condition or a threshold that was
reached.
tunnel A virtual pipe between the LAC and LNS that can carry multiple L2TP sessions.
tunnel switch A term used in DSL environments. Refers to a device that accepts a PPP session from L2TP, PPTP, or
L2F and tunnels it again using L2TP, PPTP, or L2F. See also multihop.
turbo access control
list A function of the PXF pipeline that determines whether a packet matches a list in a fixed, predictable
period of time, usually regardless of the number of entries in a list. Turbo ACLs enable more expedient
packet classification and access checks when the router is evaluating ACLs. The Turbo ACL feature
compiles the ACLs into a set of lookup tables, while maintaining the first match requirements. Packet
headers are used to access these tables in a small, fixed number of lookups, independently of the
existing number of ACL entries.
U
UBR Unspecified bit rate. QoS class defined by the ATM Forum for ATM networks. UBR allows any amount
of data up to a specified maximum to be sent across the network, but there are not guarantees in terms
of cell loss rate and delay.
UNI signaling User Network Interface signaling for ATM communications.
upstream rate The line rate for message or data transfer from the source machine to a destination machine on the
network.
V
VAI Virtual Access Interface.
VBR Variable Bit Rate. QoS class defined by the ATM Forum for ATM networks. VBR is subdivided into a
real time (rt) class and non-real time (nrt) class. See also VBR-nrt and VBR-rt.
VBR-nrt Variable Bit Rate-non-real time. QoS class defined by the ATM Forum for ATM networks. VBR-nrt is
used for connections in which there is no fixed timing relationship between samples, but that still need
a guaranteed QoS.
VBR-rt Variable Bit Rate-real time. QoS class defined by the ATM Forum for ATM networks. VBR-rt is used
for connections in which there is a fixed timing relationship between samples.