Ospfv2 Stub Router Advertisements; Multiple Ospfv2 Instances; Spf Optimization; Virtualization Support - Cisco Nexus 7000 Series Configuration Manual

Licensing Requirements for OSPFv2

S e n d d o c u m e n t c o m m e n t s t o n e x u s 7 k - d o c f e e d b a c k @ c i s c o . c o m .

OSPFv2 Stub Router Advertisements

You can configure an OSPFv2 interface to act as a stub router using the OSPFv2 Stub Router
Advertisements feature. Use this feature when you want to limit the OSPFv2 traffic through this router,
such as when you want to introduce a new router to the network in a controlled manner or limit the load
on a router that is already overloaded. You might also want to use this feature for various administrative
or traffic engineering reasons.
OSPFv2 stub router advertisements do not remove the OSPFv2 router from the network topology, but
they do prevent other OSPFv2 routers from using this router to route traffic to other parts of the network.
Only the traffic that is destined for this router or directly connected to this router is sent.
OSPFv2 stub router advertisements mark all stub links (directly connected to the local router) to the cost
of the local OSPFv2 interface. All remote links are marked with the maximum cost (0xFFFF).

Multiple OSPFv2 Instances

Cisco NX-OS supports multiple instances of the OSPFv2 protocol that run on the same node. You cannot
configure multiple instances over the same interface. By default, every instance uses the same system
router ID. You must manually configure the router ID for each instance if the instances are in the same
OSPFv2 autonomous system.

SPF Optimization

Cisco NX-OS optimizes the SPF algorithm in the following ways:
•
•

Virtualization Support

OSPFv2 supports Virtual Routing and Forwarding instances (VRFs). VRFs exist within virtual device
contexts (VDCs). By default, Cisco NX-OS places you in the default VDC and default VRF unless you
specifically configure another VDC and VRF. You can have up to four instances of OSPFv2 in a VDC.
Each OSPFv2 instance can support multiple VRFs, up to the system limit. For more information, see the
Cisco Nexus 7000 Series NX-OS Virtual Device Context Configuration Guide, Release 4.x and see
Chapter 14, "Configuring Layer 3 Virtualization."
Licensing Requirements for OSPFv2
The following table shows the licensing requirements for this feature:
Cisco Nexus 7000 Series NX-OS Unicast Routing Configuration Guide, Release 4.x
6-12
Partial SPF for Network (type 2) LSAs, Network Summary (type 3) LSAs, and AS External (type
5) LSAs—When there is a change on any of these LSAs, Cisco NX-OS performs a faster partial
calculation rather than running the whole SPF calculation.
SPF timers—You can configure different timers for controlling SPF calculations. These timers
include exponential backoff for subsequent SPF calculations. The exponential backoff limits the
CPU load of multiple SPF calculations.
Chapter 6 Configuring OSPFv2
OL-20002-02