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MULTIPLE NETWORK LAYER SUPPORT

• Eigrp supports IP, APPLETALK and Novell Netware Internet packet exchange(IPX) through the use of PROTOCOL DEPENDANT MODULES

• Eigrp does not require any special configuration to work across Layer2 Protocols

• ospf uses different configuration for different Layer2 Protocols , such as Ethernet and Frame-relay

• Eigrp represent values in 32 bit format for additional granularity

1. Neighbor discovery / recovery
2. Reliable Transport Protocol RTP
3. DUAL finite state machine
4. Protocol Dependant Modules (PDM'S)
   

• Guaranteed ordered delivery of EIGRP packets .

• Intermixed transmission of Multicast and Unicast Packets
  

• Responsible for network layer Protocol Specific requirements

• IP Eigrp module is responsible for sending and receiving eigrp pakects that are encapsulated in IP

• The ip-eigrp also responsible for parsing Eigrp Packets and informing DUAL of the new Information received
  

• Ip-eigrp asks Dual to make routing decisions , the results ofwhich are stored in ip routing table

• Ip-eigrp is responsible for re-distributing routes learned by other ip routing protocols

• AD = cost of next hop router and destination

• FD = cost from local router + cost between Local router and next hop router

• A Recomputation occurs when destination has no Feasible Successor
  

• Recomputation is the way to determine new successor when feasible successor are absent
  

• Recomputation is not processor intensive
  

• Its always better to avoid Re-Computation

• In the process , if the neighbor router has a route for destination , it sends a reply packet

• If it does not have a router it sends QUERY packet
  

• While the destination in active state , a router cannot change the Destination routing table information