SDN and NFV is the next phase of technology change which will help service provider to launch the services in single click. This is all about the programmability of the networks by using open source software defined network controller.
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Wednesday, December 5, 2012
What is Discard Route or NULL0 Route?
What is Discard Routes and how does it help to stop layer 3 routing loops? As we know the fact that loops are not only originates in layer2 network but could also originate in layer 3 networks. We have various mechanisms to prevent layer 3 routing loops with spit horizon and route poisoning.
Would like to understand; IS there any kind of other scenario where in routing loop could exist? See the below infographic
As depicted above, routing loop could occur whenever a summary route is announced towards the peer. This loop could be stopped by creating a manual discard route pointing towards null interface.
IP Route 10.2.0.0 255.255.0.0 null0
OSPF, IS-IS and EIGRP automatically creates discard route whenever summary is performed on the routers.
Below are the configurations for disabling discard routes:-
OSPF
router ospf 1
no discard route
EIGRP
interface serial0 ip summary-address eigrp 1 10.2.0.0 255.255.0.0 255
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