Tag: k4

CCNP Route 300-101 – EIGRP

by Samuel Mitchell, posted in Cisco, Routing & Switching

EIGRP routing protocol for IPv4 and IPv6

  • Default hello messages timer: 5 seconds
  • Default hold-down timer: 15 seconds
  • Multicast address: 224.0.0.10 (IPv4) / FF02::A (IPv6)
  • IP Protocol: 88
  • Administrative distance of 90
  • Autonomous Number is required to be the same with the neighbors.

Basic EIGRP Configuration

!IPv4 EIGRP configuration

R(config)# router eigrp [AS]

R(config)#network [subnet] [wildcard_mask]

!IPv6 EIGRP configuration

R(config)# ipv6 router eigrp 1
R(config-router) eigrp router-id [X.X.X.X]
R(config-router) no shutdown

!Configure command under participating interface in IPv6 EIGRP

R(config-if) ipv6 eigrp [AS]

EIGRP Metrics

To enable to metric for EIGRP, you use the following commands:

R(config-router)# metric weights 0 [K1] [K2] [K3] [K4] [K5]

Where the K values are:

  • K1 – Bandwidth [Kbit/sec] (default 1)
  • K2 –  Load (default 0)
  • K3 – Delay (default 1)
  • K4 and K5 – Reliability (default 0)

Calculating the full Metric (Formula)

Metric = ([K1 * bandwidth + (K2 * Bandwidth) / (256 – Load) + K3 * Delay] * [K5 / (Reliability + K4)]) * 256

Calculating the Default Metric

eigrp_metric_calculation

EIGRP Packets

  • Hello (5)

eigrp_hello

  • Update (1)

eigrp_update

  • Query (3)

eigrp_query

  • Reply (4)

eigrp_reply

  • Ack (5)

eigrp_Hello_Ack

Administrative Distance (AD) – is how far is the router from it’s neighbor.

Feasible Distance (FD) – is how far is the router for the destination subnet.eigrp_diagram

  • R1 FD from 10.1.1.0/24 through R3
    • = (R1–>R3) + (R3–>R4) + (subnet 10.1.1.0/24)
    • = 5 + 5 + 1 = 11

 

Feasible successor – the advertised distance (AD) must be less than the feasible distance (FD) of the Successor (Feasible Successor AD < Successor FD)

EIGRP Neighborship

When the neighbor command is used, it forces the EIGRP to use unicast traffic to discover the neighbor.

R1(config-router)# neighbor [ip address]

The command and out display of the EIGRP neighbor:

show ip eigrp neighbors

show_eigrp_neighbor-cmd

As i continue my studies, this article will be updated.