EIGRP Operations

Which tables supported in EIGRP router

Support three tables

Neighbor table

Topology table

Routing table

EIGRP operation is based on these three tables

What information contained neighbor table

Set of neighbors with which EIGRP router has established adjacencies

What is the command to display neighbor table

Show ip eigrp neighbor

How neighbor routers are characterized

By their primary IP address and the directly connected interface that leads to them

What does topology table contain

All destination routes advertised by the neighbor routers

Each entry in topology table associated with a list of neighbor that have advertised the destination

For each neighbor, an advertised metric is recorded in the topology table

What is the command to display topology table

Show ip eigrp topology

What is routing table

Table has best routes to destination

What is the command to display routing table

Show ip route eigrp

1) The route with the best metric to the destination is called the ______

Where successor or best path is placed

Routing table

Advertised to neighbor router

Neighbor process

R1 sends hello packets on all EIGRP enabled interfaces

R2 receive the hello packet on its interface

  R2 reply with update packets

  Update packets contain all routes from R2 routing table

  Routes learned via split horizon not included into update

R2 send update packet to R1

  Neighbor relationship is not established until R2 sends a hello packet to R1

Update packet from R2 has initialization bit set

  Indicate the initialization process

Update packet include routes and metric for each destination

Both R1 and R2 have exchanged hello packets

  Neighbor adjacency is established

R1 replies to R2 with ACK packet

  Indicate that update packet is received

R1 assimilates all the update packet in its topology table

 Topology table include all the destination that are advertised by neighbor router

R1 send update packet to R2

R2 send an ACK packet to R1

R1 and R2 successfully exchange update packets

R1 and R2 will update their routing tables with successor routes from topology table

1)  Successor

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