OSPF is not a Cisco-proprietary routing protocol. It is an industry standard protocol supported by a wide range of vendors. The following are characteristics of OSPF:
* Uses Internet Protocol (IP) protocol 89.
* Has a default administrative distance of 110.
* Is an industry standard protocol (non Cisco-proprietary).
* Supports Non-Broadcast Multi-Access (NBMA) networks such as frame relay, X.25, and Asynchronous Transfer Mode (ATM). The default hello interval for NBMA networks is 30 seconds.
* Supports point-to-point and point-to-multipoint connections.
* Supports authentication.
* Uses 224.0.0.6 as multicast address for ALLDRouters.
* Uses 224.0.0.5 as multicast address for ALLSPFRouters.
* Uses link-state updates and SPF calculation that provides fast convergence.
* Recommended for large networks due to good scalability.
* Uses cost as the default metric.