Ospf Vpn Extension - HP HSR6800 Configuration Manual

With MP-IBGP, to advertise routes between IBGP peers, the SPE acts as the RR and advertises
routes from IBGP peer UPE to IBGP peer SPE. However, it does not act as the RR of the other PEs.
Recursion and extension of HoVPN
HoVPN supports HoPE recursion:
•
A HoPE can act as a UPE to form a new HoPE with an SPE.
•
A HoPE can act as an SPE to form a new HoPE with multiple UPEs.
•
HoVPN supports multi-level recursion.
With recursion of HoPEs, a VPN, in theory, can be extended infinitely.
Figure 79 Recursion of HoPEs
Figure 79 shows a three-level HoPE. The PE in the middle is called the "middle-level PE (MPE)."
MP-BGP runs between SPE and MPE, and between MPE and UPE.
NOTE:
The term "MPE" does not really exist in an HoVPN model. It is used here just for the convenience of
description.
MP-BGP advertises all the VPN routes of the UPEs to the SPEs, and advertises the default routes of
the VPN instance of the SPEs or the VPN routes permitted by the routing policies to the UPEs.
The SPE maintains the VPN routes of all sites in the HoVPN. Each UPE maintains only VPN routes
of its directly connected sites. An MPE has fewer routes than the SPE but has more routes than a
UPE.

OSPF VPN extension

This section focuses on the OSPF VPN extension. For more information about OSPF, see Layer
3—IP Routing Configuration Guide.
OSPF for VPNs on a PE
OSPF is a prevalent IGP protocol. It often runs between a PE and a CE to simplify CE configuration
and management because the CEs only need to support OSPF. In addition, if the customers require
MPLS L3VPN services through conventional OSPF backbone, using OSPF between a PE and a CE
can simplify the transition.
For OSPF to run between CE and PE, the PE must support multiple OSPF processes. Each OSPF
process must correspond to a VPN instance and have its own interface and routing table.
Details of OSPF configuration between a PE and a CE are described here.
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