?– Large MPLS Edge Routers provide the N-PE layer for L2 VPNs and the PE layer
for L3 VPNs.
MPLS 453
?– Smaller MPLS-enabled nodes provide the U-PE layer for L2 VPNs and a pseudowire
access layer toward the L3 VPN PEs (this requires ???pseudowire into VRF???
capability at the L3 VPN PEs).
?– Layer 2 Ethernet switches provide access to the MPLS network, acting as 802.1ad
Provider Bridges.
Metro Core for Ethernet over Multiple Access Networks
Many service providers use a mixture of on-net and off-net facilities to reach enterprise
customers. However, these providers still face the market demand to deliver IP and
Ethernet services and to use Ethernet as the standard interface for handoff to their
customers. Many such providers are moving to a model where one or two EoMPLS PE
devices are deployed into each city (or several into a large city) and are connected to
each other over MPLS and to their service platforms (such as IP-VPN PE devices and
public Internet routers) over Ethernet NNIs (often provisioned today using VLANs
over gigabit Ethernet ports). Customers connect to provider-owned network demarcation
devices that have Ethernet ports toward the customer and Ethernet, Ethernet
over SONET/SDH, Ethernet over TDM, or Ethernet over DSL interfaces toward the
network.
Pages:
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025