3com 8807 User Guide
47
MPLS A
RCHITECTURE
n
The 3Com Switch 8800 Family Series Routing Switches (hereinafter referred to as
Switch 8800 Family series) running MPLS can serve as routers. Routers mentioned
in this manual can be either a router in common sense, or a layer 3 Ethernet
switch running MPLS.
Switch 8800 Family series) running MPLS can serve as routers. Routers mentioned
in this manual can be either a router in common sense, or a layer 3 Ethernet
switch running MPLS.
MPLS (Multiprotocol Label Switching) encapsulates network layer packets with
short and fixed-length labels. As the name implies, it supports multiple protocols,
such as IP, IPv6, and IPX. And it allows a device to make forwarding decision based
on the labels attached to the received packets without going through the complex
routing table lookup procedures with IP. MPLS brings together the advantages of
the connectionless control with IP and the connection-oriented forwarding with
ATM. In addition to the support from IP routing and control protocols, its powerful
and flexible routing functions allows it to accommodate to various emerging
applications.
short and fixed-length labels. As the name implies, it supports multiple protocols,
such as IP, IPv6, and IPX. And it allows a device to make forwarding decision based
on the labels attached to the received packets without going through the complex
routing table lookup procedures with IP. MPLS brings together the advantages of
the connectionless control with IP and the connection-oriented forwarding with
ATM. In addition to the support from IP routing and control protocols, its powerful
and flexible routing functions allows it to accommodate to various emerging
applications.
MPLS Overview
MPLS (Multiprotocol Label Switching) encapsulates network layer packets with
short and fixed-length labels. As the name implies, it supports multiple protocols,
such as IP, IPv6, and IPX. And it allows a device to make forwarding decision based
on the labels attached to the received packets without going through the complex
routing table lookup procedures with IP. MPLS brings together the advantages of
the connectionless control with IP. In addition to the support from IP routing and
control protocols, its powerful and flexible routing functions allows it to
accommodate to various emerging applications.
short and fixed-length labels. As the name implies, it supports multiple protocols,
such as IP, IPv6, and IPX. And it allows a device to make forwarding decision based
on the labels attached to the received packets without going through the complex
routing table lookup procedures with IP. MPLS brings together the advantages of
the connectionless control with IP. In addition to the support from IP routing and
control protocols, its powerful and flexible routing functions allows it to
accommodate to various emerging applications.
MPLS was initially proposed to accelerate the packet forwarding on routers, but it
has been widely used in Traffic Engineering (TE), Virtual Private Network (VPN),
and other aspects, and is becoming one of the most important standards on large
scale IP networks.
has been widely used in Traffic Engineering (TE), Virtual Private Network (VPN),
and other aspects, and is becoming one of the most important standards on large
scale IP networks.
MPLS Basic Concepts
FEC
Forwarding Equivalence Class (FEC) is an important concept in MPLS. MPLS is
actually a kind of classify-and-forward technology. It categorizes packets with the
same forwarding strategy (same destination addresses, same forwarding routes
and same QoS levels) into one class, which is called a FEC. Generally, the FEC
classification is based on network layer address. Packets of the same FEC are
processed in the same way in MPLS network.
actually a kind of classify-and-forward technology. It categorizes packets with the
same forwarding strategy (same destination addresses, same forwarding routes
and same QoS levels) into one class, which is called a FEC. Generally, the FEC
classification is based on network layer address. Packets of the same FEC are
processed in the same way in MPLS network.
Label
Label definition
A label is a locally significant short identifier with fixed length, which is used to
identify a FEC. When reaching at MPLS network ingress, packets are divided into
identify a FEC. When reaching at MPLS network ingress, packets are divided into