1. Activate Passive Interfaces on Router
   1. Global command configured in router mode
   2. "passive-interface default"
   3. To enable specific interfaces use "no passive-interface" command
2. Clear Adjacencies
   1. "clear ip eigrp neighbors"
3. Show Protocol Information
   1. "sh ip protocols"
4. Neighbor Table Information
   1. Seq Num
      1. Sequence # of last eigrp packet received from neighbor
   2. H (Handle)
      1. order of neighbor adjacency
      2. 0 is first, 1 is second, etc.
   3. Hold Uptime
      1. Adjacency is dropped if timer expires
   4. SRTT (Smooth Round Trip)
      1. time to send eigrp packet to neighbor and receive ACK
   5. RTO (Retransmission Timeout)
      1. time eigrp will wait to retransmit a packet from retransmission queue
   6. Q Cnt (Q Count)
      1. # of eigrp packets in the queue awaiting transmission
5. Topology Table Information
   1. Codes
      1. Passive
         1. Good...no changes to table
      2. Active
         1. Not good...sends query packets to all neighbors for lost routes
      3. SIA Status
         1. Very bad. Stuck In Active
            1. No reply to a query packet within 3 minutes
            2. Adjacency is dropped
      4. Query
      5. Reply
      6. Reply Status
         1. EIGRP tracks all sent query packets for a reply
   2. Metrics
      1. Feasible Distance
         1. Administrative Distance
6. Routing Table Information
   1. Best routes from topology table included here
   2. Codes
      1. C - Connected
      2. O - OSPF
      3. D - EIGRP
      4. R - RIP
      5. B - BGP
      6. M - Mobile
      7. IA - OSPF Interarea
      8. S- Static
      9. EX - External EIGRP
   3. DUAL Algorithm
      1. Used to calculate routes
   4. Metrics
      1. Administrative Distance
         1. Feasible Distance
7. Metrics
   1. Bandwidth (K1)
      1. enabled by default
         1. static value
         2. "bandwidth" command on interface influences routing
   2. Load (K2)
      1. dynamic value
   3. Delay (K3)
      1. enabled by default
         1. static value
         2. "delay ____" command on interface influences routing
   4. Reliability (K4)
      1. dynamic value
         1. value decreases if interface has issues
   5. MTU (K5)
      1. not used in metric calculation
   6. ***K2 & K4 not used in formula for metric calculation***
      1. metric = bandwidth (slowest link) + delay (sum of delays)
         1. Bandwidth: [10,000,000 / slowest link in path x 256
         2. Delay: [Sum of delays in path x 256]