Cisco Nexus 7000 Series - VRF and Routing; VRF-Aware Services

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14-3
Cisco Nexus 7000 Series NX-OS Unicast Routing Configuration Guide, Release 4.x
OL-20002-02
Chapter 14 Configuring Layer 3 Virtualization
Layer 3 Virtualization
VRF and Routing
All unicast and multicast routing protocols support VRFs. When you configure a routing protocol in a
VRF, you set routing parameters for the VRF that are independent of routing parameters in another VRF
for the same routing protocol instance.
You can assign interfaces and route protocols to a VRF to create virtual Layer 3 networks. An interface
exists in only one VRF. Figure 14-2 shows one physical network split into two virtual networks with two
VRFs. Routers Z, A, and B exist in VRF Red and form one address domain. These routers share route
updates that do not include router C because router C is configured in a different VRF.
Figure 14-2 VRFs in a Network
By default, Cisco NX-OS uses the VRF of the incoming interface to select which routing table to use for
a route lookup. You can configure a route policy to modify this behavior and set the VRF that Cisco
NX-OS uses for incoming packets. See Chapter 17, “Configuring Policy-Based Routing” for more
information.
Cisco NX-OS prevents route leakage(import or export) between VRFs.
VRF-Aware Services
A fundamental feature of the Cisco NX-OS architecture is that every IP-based feature is VRF aware.
The following VRF-aware servics can select a particular VRF to reach a remote server or to filter
information based on the selected VRF:
• AAA—See the Cisco Nexus 7000 Series NX-OS Security Configuration Guide, Release 4.x for more
information.
• Call Home—See the Cisco Nexus 7000 Series NX-OS System Management Configuration Guide,
Release 4.x for more information.
• DNS—See Chapter 4, “Configuring DNS” for more information.
• GLBP—See Chapter 18, “Configuring GLBP” for more information.
• HSRP—See Chapter 19, “Configuring HSRP” for more information.
• HTTP—See the Cisco Nexus 7000 Series NX-OS Fundamentals Configuration Guide, Release 4.x
for more information.
• Licensing—See theCisco NX-OS Licensing Guide for more information.
• NetFlow—See the Cisco Nexus 7000 Series NX-OS System Management Configuration Guide,
Release 4.x for more information.
• NTP—See the Cisco Nexus 7000 Series NX-OS System Management Configuration Guide, Release
4.x for more information.
Ethernet 1/1
VRF Red
Ethernet 2/1
VRF Red
Ethernet 2/2
VRF Blue
Router Z
Router A
Router B
Router C
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