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| 5.2 |  | EIGRP Features |
| 5.2.5 |  | Protocol-dependent modules |

The modular design is one of the most attractive features of EIGRP. Modular designs prove to be the most scalable and adaptable. Support for routed protocols such as IP, IPX, and AppleTalk is included in EIGRP through protocol-dependent modules (PDMs). In theory, EIGRP can easily adapt to new or revised routed protocols by adding protocol-dependent modules.

Each PDM is responsible for all functions related to its specific routed protocol. The IP-EIGRP module is responsible for the following:

- Sending and receiving EIGRP packets that bear IP data
- Notifying DUAL of new IP routing information that is received
- Maintaining the results of DUAL routing decisions in the IP routing table
- Redistributing routing information that was learned by other IP-capable routing protocols