simple question on OSPF: contents of the OSPF Hello message

Hi guys,

According to cisco press book, below items are present in OSPF hello messages:

■ OSPF Router ID
■ Stub area flag
■ Plus the following interface-specific settings:
■ Hello interval
■ Dead Interval
■ Subnet mask
■ List of neighbors reachable on the interface
■ Area ID
■ Router priority
■ Designated Router (DR) IP address
■ Backup DR (BDR) IP address
■ Authentication digest

What do they mean with 'list of neighbors reachable on the interface' ?
If R1 sends hello packet to R2 through S0/0, only neighbor on that interface is R2... or it will be...

Am I getting this right?

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Comments

networker050184

Yep pretty much. But there are instances when a router will have multiple neighbors out of a single interface.

aocferreira

You are talking about frame relay topologies, for example? Yea it makes sense...

It was just to confirm as it was not making much sense to me that sentence

Thanks!

networker050184

Not only frame relay, but also an ethernet segment which is much more common.

Kory

The other purpose of the field is to trigger a state change in the relationship. Because, when the router sees its own address in that neighbor field, it moves to 2-way state.