Configuring EIGRP
EIGRP Configuration Task List
IPC-261
Cisco IOS IP Configuration Guide
To adjust the EIGRP metric weights, use the following command in router configuration mode:
By default, the EIGRP composite metric is a 32-bit quantity that is a sum of the segment delays and the
lowest segment bandwidth (scaled and inverted) for a given route. For a network of homogeneous media,
this metric reduces to a hop count. For a network of mixed media (FDDI, Ethernet, and serial lines
running from 9600 bits per second to T1 rates), the route with the lowest metric reflects the most
desirable path to a destination.
Mismatched K Values
Mismatched K values (EIGRP metrics) can prevent neighbor relationships from being established and
can negatively impact network convergence. The following example explains this behavior between 2
EIGRP peers (ROUTER-A and ROUTER-B).
The following error message is displayed in the console of ROUTER-B because the K values are
mismatched:
*Apr 26 13:48:41.811: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 1: Neighbor 10.1.1.1 (Ethernet0/0) is
down: K-value mismatch
There are two scenarios where this error message can be displayed:
•The two routers are connected on the same link and configured to establish a neighbor relationship.
However, each router is configured with different K values.
The following configuration is applied to ROUTER-A. The K values are changed with the metric
weights command. A value of 2 is entered for the k1 argument to adjust the bandwidth calculation.
The value of 1 is entered for the k3 argument to adjust the delay calculation.
hostname ROUTER-A!
interface serial 0
ip address 10.1.1.1 255.255.255.0
exit
router eigrp 100
network 10.1.1.0 0.0.0.255
metric weights 0 2 0 1 0 0
The following configuration is applied to ROUTER-B. However, the metric weights command is
not applied and the default K values are used. The default K values are 1, 0, 1, 0, and 0.
hostname ROUTER-B!
interface serial 0
ip address 10.1.1.2 255.255.255.0!
exit
router eigrp 100
network 10.1.1.0 0.0.0.255
The bandwidth calculation is set to 2 on ROUTER-A and set to 1 (by default) on ROUTER-B. This
configuration prevents these peers from forming a neighbor relationship.
Command Purpose
Router(config-router)# metric weights tos k1 k2 k3 k4 k5 Adjusts the EIGRP metric or K value. EIGRP uses the
following formula to determine the total metric to the
network:
metric = [K1*bandwidth + (K2*bandwidth)/(256 - load)
+ K3*delay] * [K5/(reliability + K4)]