A policy-based router that uses methods such as Multiprotocol Label Switching (MPLS) or Border Gateway Protocol (BGP) is required to properly route the packets from the IP Managers. Packets that are routed through a policy-based router shows this example, where such a router must have two interfaces, Interface A and Interface B, through which there is unambiguous connectivity to networks of Customers A and Customer B, respectively.
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IP
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Manager_B
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IP
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Manager_A
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Packet to IP Manager_A (Domain A)
A policy route must be defined such that a packet that originates from IP Manager_A, whose source address is Virtual A, is forwarded through Interface A. Similarly, a second route must be defined such that a packet that originates from IP Manager B, whose source address is Virtual B, is forwarded though Interface B.
Routers that route packets from the customer networks through Interface A and Interface B use standard IP routing to route the packets to the appropriate interface and the IP Manager.