Cisco CCNA Examination Tutorial: 5 OSPF Hub-And-Spoke Specifics You Must Know!
CCNA Examination achievements depends greatly on figuring out the main points, and if there’s 1 protocol that has a large amount of particulars, it’s OSPF! This is certainly legitimate specifically of hub-and-spoke networks, so In this particular CCNA OSPF tutorial we’ll take a look at several of the more vital hub-and-spoke OSPF particulars. This can help you in working with serious-environment networks as well, due to the fact this OSPF community style is among the far more typical network topologies.
In OSPF, the hub will have to grow to be the selected router (DR). The DR election’s choosing value could be the OSPF interface precedence, plus the default worth is 1. It’s not sufficient to established the hub’s OSPF interface to 토토사이트 two, even so, Considering that the spoke routers ought to not grow to be the DR or BDR. You will need to established the spoke interfaces to an OSPF priority of zero.
R2(config-if)#ip ospf priority 0
This ensures that the spokes will likely not come to be the DR or BDR Should the hub goes down.
The hub does demand a little bit more configuration, though. The neighbor command has to be made use of within the hub to indicate the IP address with the likely neighbors.
R1(config)#router ospf one
It’s typical to obtain an ISDN link as a backup in an OSPF network, and when that ISDN url will come up the hello packets have to be capable to cross the backlink. Anything you don’t want would be to contain the hellos preserve the backlink up! By configuring the ISDN hyperlink being an OSPF demand from customers circuit, the url will fall during the absence of fascinating website traffic, even so the OSPF adjacency that shaped over the ISDN website link are going to be assumed by the router to however be up. (You usually see this command configured on either side with the ISDN hyperlink, but it really’s only desired http://query.nytimes.com/search/sitesearch/?action=click&contentCollection®ion=TopBar&WT.nav=searchWidget&module=SearchSubmit&pgtype=Homepage#/먹튀검증 on a person facet. It doesn’t hurt anything at all to put it on either side, although.)
R2(config-if)#ip ospf desire-circuit
A last element of OSPF hub-and-spoke and demand from customers circuits actually takes put at Layer 2. With the OSPF good day packets to productively be transmitted throughout an ISDN backlink or perhaps a frame relay community, the printed choice should be enabled in the suitable body and dialer map statements. Failure to empower this option can cause a predicament the place pings might be productive, but OSPF adjacencies will likely not kind.
R2(config-if)#dialer map ip 172.12.21.one name R1 broadcast 5551111
R2(config-if)#body map ip 188.8.131.52 221 broadcast
Any time you’re troubleshooting OSPF in a very manufacturing community or your CCNA / CCNP house lab, don’t just have a look at Layer 3 – mainly because everything’s received to be appropriate with the Actual physical and info link levels to ensure that the network layer to function properly!