| One of EIGRP's most attractive
features is its modular design. Modular, layered 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 (e.g., IPv6) 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's
routing decisions in the IP routing table
- Redistributing routing information
that was learned by other IP-capable routing protocols
|