OSPF Network Types

OSPF NETWORK TYPES

There are five different network types within which OSPF operates. The following list explains the characteristics of the OSPF network types:

OSPF Network types

 

Broadcast

  • The Broadcast network type is the default for an OSPF enabled Ethernet interface.
  • The Broadcast network type requires that a link support Layer 2 Broadcast capabilities.
  • The Broadcast network type has a 10 second hello and 40 second dead timer.
  • An OSPF Broadcast network type requires the use of a DR/BDR.

Non-Broadcast

  • The Non-Broadcast network type is the default for OSPF enabled frame relay physical interfaces.
  • Non-Broadcast networks requires the configuration of static neighbors; hello’s are sent via unicast.
  • The Non-Broadcast network type has a 30 second hello and 120 second dead timer.
  • An OSPF Non-Broadcast network type requires the use of a DR/BDR

Point-to-Point

  • A Point-to-Point OSPF network type does not maintain a DR/BDR relationship.
  • The Point-to-Point network type has a 10 second hello and 40 second dead timer.
  • Point-to-Point network types are intended to be used between 2 directly connected routers.

Point-to-Multipoint Non-Broadcast

  • Same as Point-to-Multipoint but requires static neighbors. Used on Non-broadcast layer 2 topologies.
  • Gives you the ability to define link cost on a per neighbor basis.

Point-to-Multipoint

  • OSPF treats Point-to-Multipoint networks as a collective of point-to-point links.
  • Point-to-Multipoint networks do not maintain a DR/BDR relationship.
  • Point-to-Multipoint networks advertise a hot route for all the frame-relay endpoints.
  • The Point-to-Multipoint network type has a 30 second hello and 120 second dead timer.

Comparison Table: OSPF Network Types

To summarize , we can enumerate the OSPF Network Types in the below table –

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MODE

PREFERRED

TOPOLOGY

SUBNET

ADDRESS

ADJACENCY

RFC or CISCO

Non-Broadcast Fully Meshed Same Manual configuration

DR/BDR elected

RFC
Broadcast Fully Meshed Same Automatic

DR/BDR elected

Cisco
Point-to-multipoint Partial Mesh or Star Same Automatic

No DR/BDR

RFC
Point-to-multipoint

Non broadcast

Partial Mesh or Star Same Manual configuration

No DR/BDR

Cisco
Point-to-point Partial Mesh or star, using sub interface Different for each subnet Automatic

No DR/BDR

Cisco

Download the table: OSPF Network Types

Continue Reading:

OSPF LSA Types The Ultimate Guide

OSPF Router Types: Detailed Explanation

 

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