About this interactive
An OSPF network statement, such as network 10.1.20.0 0.0.0.255 area 0, matches each interface whose IP address falls in the range its wildcard mask allows: a 0 bit must match, a 1 bit can be anything. On every matched interface it does two things:
1. The interface sends hellos, looking for OSPF neighbors on that link (which is why you may not want it on a user VLAN).
2. The interface's network is advertised to the neighbors the router forms adjacencies with.
A broad statement such as network 10.0.0.0 0.255.255.255 area 0 matches every 10.x.x.x interface at once; a wildcard of 0.0.0.0 matches one exact address.
What you'll learn
- Decide whether an OSPF network statement matches an interface, by applying its wildcard mask to the interface's address
- Explain the statement's two effects on a matched interface: it sends hellos there, and its network is advertised to neighbors
Aligned to
Cisco CCNA
3.4
Configure and verify single area OSPFv2
Key terms
- OSPF Network Statement
- A configuration command that identifies which interfaces and directly connected networks will participate in the OSPF routing process.
- Wildcard Mask
- A 32-bit mask used in ACL statements and OSPF network commands where a 0 bit means the corresponding address bit must match and a 1 bit means it can be anything. Wildcard masks are the inverse of subnet masks and allow a single statement to match an entire range of IP addresses.
- Hello Packet
- An OSPF control message sent periodically on active interfaces to discover neighbors, verify reachability, and maintain adjacencies.
Topics
Ospf
Network Statement
Wildcard Mask
Ospf Configuration
Interactive
Streak Sort
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