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Integrating Internet Access with MPLS VPNs. Implementing Separate Internet Access and VPN Services. Outline. Overview Classical Internet Access for a VPN Customer Using S eparate S ubinterfaces Accessing the Internet from Every Customer Site S eparate Internet Access Benefits and
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Integrating Internet Access with MPLS VPNs Implementing Separate Internet Access and VPN Services
Outline • Overview • Classical Internet Access for a VPN Customer • UsingSeparate Subinterfaces • Accessing the Internet from Every Customer Site • Separate Internet Access Benefits and • Limitations Summary
Using Separate Subinterfaces • Separate physical links for VPN and Internet traffic are sometimes not acceptable because ofhigh cost. • Subinterfaces could be used. • Over WAN links using Frame Relay or ATM encapsulation (including xDSL) • Over LAN links • A tunnel interface could be used. • Over a VRF-aware tunnel, so that VPN traffic does not run over a global tunnel
Internet Access Through a Dedicated Subinterface—Traffic Flow
Internet Access at Every Customer Site • Every CE router needs two links (or subinterfaces) to its PE router. • Using a separate link or links for Internet access will lead to a complex setup for this customer type.
Benefits and Limitations of Separate Internet Access for the Service Provider • Benefits: • Well-known model • Supports all customer requirements • Allows all Internet services implementations, including a BGP session with the customer • Drawbacks: • This design model requires separate physical link or specific WAN encapsulation. • PE routers must be able to perform Internet routing (and potentially carry full Internet routing). • Wholesale Internet access or central firewall service cannot be implemented with this model.
Summary • Classical Internet access for a VPN customer is based on a separated Internet access design model • Separate subinterfaces can be used for implementing Internet access through global routing • Internet access from every customer site can be supported but is often too complex or too expensive with classic Internet access. • The main drawback of separate Internet access is that PE routers potentially carry full Internet routing table