Chapter 12 Configuring Vrf Lite; Understanding Vrf Lite - Cisco ONS 15454 Software Feature And Configuration Manual

Configuring VRF Lite
This chapter describes how to configure VPN Routing and Forwarding Lite (VRF Lite) for the
ML-Series cards. For additional information about the Cisco IOS commands used in this chapter, refer
to the Cisco IOS Command Reference publication. This chapter contains the following major sections:
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Note You may have already configured bridging, and you may now proceed with configuring VRF Lite as an
optional step.

Understanding VRF Lite

VRF is an extension of IP routing to provide multiple routing instances. It provides a separate IP routing
and forwarding table to each VPN. It is used in concert with MP-iBGP (Multi-Protocol internal BGP)
between provider equipment (PE) routers to provide Layer 3 MPLS-VPN. However, ML-Series VRF
implementation is without MP-iBGP. With VRF Lite, the ML Series is considered as either a
PE-extension or a customer equipment (CE)-extension. It is considered a PE-extension since its has VRF
(but without MP-iBGP); it is considered a CE-extension since this CE can have multiple VRFs and
serves many customer with one CE box.
Under VRF Lite, an ML-Series CE can have multiple interfaces/subinterfaces with PE for different
customers (while a normal CE is only for one customer). It holds VRFs (routing information) locally; it
does not distribute the VRFs to its connected PE(s). It uses VRF information to direct traffic to the
correct interfaces/subinterfaces when it receives traffic from customers' routers or from Internet service
provider (ISP) PE router(s).
Cisco ONS 15454 SONET/SDH ML-Series Multilayer Ethernet Card Software Feature and Configuration Guide, R4.0
78-15224-02
Understanding VRF Lite, page 12-1
Configuring VRF Lite, page 12-2
VRF Lite Configuration Example, page 12-3
Monitoring and Verifying VRF Lite, page 12-8
C H A P T E R
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