OSPF Network Types
The four different network types within which OSPF operates.
The following list explains the characteristics of the OSPF network types:
- Broadcast-A network type that connects two or more OSPF routers over a broadcast
media such as Ethernet or FDDI. Neighbor relationships are developed using OSPF
Hellos; from that, a designated router (DR) and backup designated router (BDR) are
formed via adjacencies to them.
NOTE The next section fully explains OSPF neighbor relationships, adjacencies, and DRs.
- Nonbroadcast multiaccess (NBMA)-NBMA networks do not allow broadcasts by default; examples include frame relay, ATM, or X.25 networks. NBMA networks also have the potential for multiple adjacencies, but because they do not all send broadcasts, they cannot guarantee the proper relationships will form.
- Point-to-multipoint-A method of configuring NBMA networks that allows OSPF to operate as if the routers were connected via point-to-point links instead of via an NBMA network. There are no DRs or BDRs in this configuration because each link is treated as a point-to-point link.
- Point-to-point-A single circuit that connects two OSPF routers, which allows a
single-neighbor relationship to be built. Some examples of this are leased lines
running Point-to-Point Protocol (PPP) or High-Level Data Link Control (HDLC).
There are no DRs or BDRs in this network type.
In this tutorial:
- OSPF Basics
- What Is a Routing Protocol?
- Basic Routing Protocol Operation
- Link-State Versus Distance Vector Routing Protocols
- Link-State Routing Protocols
- OSPF Characteristics
- Integrated Intermediate System-to-Intermediate System
- Distance Vector Routing Protocols
- Selecting a Routing Protocol
- Operational Considerations
- Protocols Supported
- Routing Hierarchies
- IP Address Management
- IP Encapsulation Support
- Technical Considerations
- Routing Updates
- Business Considerations
- SPF Overview
- OSPF Routing Hierarchy
- Hierarchical Network Design Techniques
- Routing Types Within an OSPF Network
- External Routes
- OSPF Areas
- Characteristics of a Standard OSPF Area
- Stub Areas
- Not-So-Stubby Areas
- OSPF Operational Environment
- Types of OSPF Routers
- OSPF Network Types
- Router Identification