Operation Manual – MPLS L3VPN
H3C S9500 Series Routing Switches
Chapter 1 MPLS L3VPN Configuration
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z
User access. This means that the PEs must have a large amount of interfaces.
z
VPN route managing and advertising, and user packet processing. These require
that a PE must have a large-capacity memory and high forwarding capability.
Most of the current network schemes use the typical hierarchical architecture. For
example, the MAN architecture contains typically three layers, namely, the core layer,
convergence layer, and access layer. From the core layer to the access layer, the
performance requirements on the devices reduce while the network expands.
MPLS L3VPN, on the contrary, is a plane model where performance requirements are
the same for all PEs. If a certain PE has limited performance or scalability, the
performance or scalability of the whole network is influenced.
Due to the above difference, you are faced with the scalability problem when deploying
PEs at any of the three layers. Therefore, the plane model is not applicable to the
large-scale VPN deployment.
2) HoVPN
To solve the scalability problem of the plane model, MPLS L3VPN must transition to the
hierarchical model.
In MPLS L3VPN, hierarchy of VPN (HoVPN) was proposed to meet that requirement.
With HoVPN, the PE functions can be distributed among multiple PEs, which take
different roles for the same functions and form a hierarchical architecture.
As in the typical hierarchical network model, HoVPN has different requirements on the
devices at different layers of the hierarchy.
II. Implementation of HoVPN
1)
Basic architecture of HoVPN
MPLS network
PE
PE
SPE
UPE
UPE
CE
CE
CE
CE
VPN 1
VPN 1
VPN 2
VPN 2
Site 1
Site 2
Figure 1-13
Basic architecture of HoVPN
