Frame Mode MPLS
Multiprotocol Label Switching (MPLS) is a technology that provides any-toany
connectivity between remote sites, using only a single WAN connection
per site. The �gmagic�h to MPLS is done in the WAN provider�fs network
where traffic is switched from hop to hop, rather than routed. MPLS tunnels
each company�fs traffic through the provider�fs network, providing an extra
level of separation and security. Some large companies set up their own
private MPLS networks, but most rely on the provider. Most companies just
connect their WAN edge routers to a provider MPLS edge router and have
no MPLS configuration on their own routers at all.
The destination IP network usually determines the path between sites, but
MPLS allows other considerations to influence the path, such as the following:
�¡ Virtual private network (VPN) destination
�¡ Quality of service (QoS) settings
�¡ Source address
�¡ Outbound interface
�¡ Layer 2 circuit
Having path-selection options other than IP route enables MPLS to support
non-IP protocols. MPLS uses labels that are read and acted upon at Layer 2
to indicate the selected path. MPLS routers remove the received label and
insert a new label before the packet is forwarded to the next hop.