Autosummarization Support and Configuration
Some classless routing protocols support autosummarization, defaulting to use it, but with the ability to disable it with the no autosummary router subcommand.
| Routing Protocol | Classless? | Supports Autosummarization | Defaults to Use Autosummarization? | Can Disable Autosummarization? |
|---|---|---|---|---|
| RIP-1 | No | Yes | Yes | No |
| RIP-2 | Yes | Yes | Yes | Yes |
| EIGRP | Yes | Yes | Yes | Yes |
| OSPF | Yes | No | - | - |
Autosummary impacts routers that directly connect to parts of more than one classful network, but it has no impact on routers whose interfaces all connect to the same single classful network.