CCNA certification demands that you master the basics of OSPF, and for many studying for the CCNA exam, their initial exposure to OSPF is a hub-and-spoke configuration. That is a challenging way to get started, due to the fact a hub-and-spoke configuration built over an NBMA technology such as Frame Relay requires very a bit of consideration to detail. Let's take a quick appear at a number of prevalent OSPF configuration errors and how to avoid them on your CCNA test.
Make certain the hub is the designated router and that there are no backup designated routers. This is accomplished by setting the OSPF interface priority to zero on the spoke routers. This not only guarantees that the hub wins the DR election with its default OSPF interface priority of 1, but it prevents the spokes from ever having a chance to turn into the DR or BDR.
Configure neighbor statements on the hub. cisco salary Given that we're dealing with an NBMA network, the hub cannot dynamically uncover its neighbors. Neighbor statements are not needed on the spokes. (They don't hurt anything, but they do not do something, either.)
Ultimately, if your OSPF adjacencies do not form as expected, make sure to use your OSI model understanding to strategy the dilemma. The problem could really be at Layer Two, with your Frame Relay configuration. If you don't use the "broadcast" alternative on your frame relay statements, OSPF hellos will not be transmitted successfully in between potential neighbors. OSPF hellos are multicast, but the "broadcast" choice for Frame Relay involves multicasts.
By paying particular consideration to these specifics, you are that considerably close to CCNA exam day achievement and earning your certification. I suggest that you get some encounter with configuring OSPF hub-and-spoke before taking the CCNA exam, because its by really performing tasks such as this that tends to make you supremely confident on CCNA test day.
posted by posting at
1:46 PM Saturday, October 6, 2012
