Cisco Cisco IOS Software Release 12.0(8)S 白書
tunnel mode mpls traffic-eng
MPLS Traffic Engineering 87
Glossary
affinity bits—an MPLS traffic engineering tunnel's requirements on the attributes of the links it will
cross. The tunnel's affinity bits and affinity mask must match up with the attributes of the various
links carrying the tunnel.
cross. The tunnel's affinity bits and affinity mask must match up with the attributes of the various
links carrying the tunnel.
call admission precedence—an MPLS traffic engineering tunnel with a higher priority will, if
necessary, preempt an MPLS traffic engineering tunnel with a lower priority. An expected use is that
tunnels that are harder to route will have a higher priority, and can preempt tunnels that are easier to
route, on the assumption that those lower priority tunnels can find another path.
necessary, preempt an MPLS traffic engineering tunnel with a lower priority. An expected use is that
tunnels that are harder to route will have a higher priority, and can preempt tunnels that are easier to
route, on the assumption that those lower priority tunnels can find another path.
constraint-based routing—Procedures and protocols used to determine a route across a backbone
taking into account resource requirements and resource availability, instead of simply using the
shortest path.
taking into account resource requirements and resource availability, instead of simply using the
shortest path.
flow—A traffic load entering the backbone at one point—point of presence (POP)—and leaving it
from another, that must be traffic engineered across the backbone. The traffic load will be carried
across one or more LSP tunnels running from the entry POP to the exit POP.
from another, that must be traffic engineered across the backbone. The traffic load will be carried
across one or more LSP tunnels running from the entry POP to the exit POP.
head-end—The upstream, transmit end of a tunnel.
IGP—Interior Gateway Protocol. Internet protocol used to exchange routing information within an
autonomous system. Examples of common IGPs include IGRP, OSPF, and RIP.
autonomous system. Examples of common IGPs include IGRP, OSPF, and RIP.
IS-IS—Intermediate System-to-Intermediate System. OSI link-state hierarchal routing protocol
whereby Intermediate System (IS) routers exchange routing information based on a single metric to
determine network topology.
whereby Intermediate System (IS) routers exchange routing information based on a single metric to
determine network topology.
label-switched path (LSP) tunnel—A configured connection between two routers, using label
switching to carry the packets. label-switched path (LSP)—A sequence of hops (R0...Rn) in which
a packet travels from R0 to Rn through label switching mechanisms. A -switched path can be chosen
dynamically, based on normal routing mechanisms, or through configuration.
switching to carry the packets. label-switched path (LSP)—A sequence of hops (R0...Rn) in which
a packet travels from R0 to Rn through label switching mechanisms. A -switched path can be chosen
dynamically, based on normal routing mechanisms, or through configuration.
Label Switching Router (LSR)—A Layer 3 router that forwards packets based on the value of a
label encapsulated in the packets.
label encapsulated in the packets.
LCAC—Link-level (per hop) call admission control.
LSA—Link-state advertisement. Flooded packet used by OSPF that contains information about
neighbors and path costs. In IS-IS, LSAs are used by the receiving routers to maintain their routing
tables.
neighbors and path costs. In IS-IS, LSAs are used by the receiving routers to maintain their routing
tables.
Multiprotocol Label Switching traffic engineering—MPLS traffic engineering. A
constraint-based routing algorithm for routing TSP tunnels.
constraint-based routing algorithm for routing TSP tunnels.
OSPF—Open shortest path first (OSPF). A link state routing protocol used for routing IP.
RSVP—Resource Reservation Protocol. Protocol for reserving network resources to provide
Quality of Service guarantees to application flows.
Quality of Service guarantees to application flows.
tail-end—The downstream, receive end of a tunnel.
traffic engineering—The techniques and processes used to cause routed traffic to travel through the
network on a path other than the one that would have been chosen if standard routing methods had
been used.
network on a path other than the one that would have been chosen if standard routing methods had
been used.