What is the default network type in every ospf link type?

[George-Sl]

what is the default cisco router network type in

1. normal Ethernet port to Ethernet port connection: broad cast or non-broadcast?

2. serial link: i know this one is p2p

3. .... and other types plz

[Reza Sharifi]

Hi George,

1-Ethernet is Broadcast

2-Serial p2p non-broadcast

3-NBMA

NBMA: simulates a broadcast model by electing a designated router (DR) and a backup designated router (BDR). There are two ways to simulate a broadcast model on an NBMA network: define the network type as broadcast with the ip ospf network broadcast interface sub-command or configure the neighbor statements using the router ospf command.

http://www.cisco.com/c/en/us/support/docs/ip/open-shortest-path-first-ospf/13690-18.html

HTH

[Rolf Fischer]

Hi,

2. serial link: i know this one is p2p

it depends on the link-layer technology/encapsulation:

HDLC, PPP, Frame-Relay Point-to-Point subinterface: Point-to-Point

Frame-Relay main-interface and -Point-to-Multipoint subinterface: NBMA

3. .... and other types plz

Tunnel interfaces (GRE): Point-to-Point

HTH
Rolf

[Mohamed Gaber]

The OSPF network type is automatically set based on the data link layer encapsulation of the interface.

[Gopinath_Pigili]

Hi George-SI,

1) Ethernet or Fastethernet interfaces---> default network type Broadcast

2) Serial interfaces/Tunnel Interfaces --> default network type  Point-to-Point

3)Loopback interface --> default network type Loopback

4)Fream-relay interface --> default network type NBMA (Non-Broadcast Multi-Access)

Other possible options  in Frame-relay

RFC 2328-Compliant mode
 Non-Broadcast (NBMA) - by default
Point-to-Multipoint

Additional Modes from Cisco
Point-to-Multipoint Non-Broadcast
Broadcast

Point-to-Point

Best regards
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