Goodbye Message; Percentage Of Link Bandwidth Used For Eigrp Packets; Floating Summary Routes For An Eigrp Process - Cisco NCS 6000 Series Configuration Manual

Goodbye Message

• The K-value mismatch error message can also be displayed if one of the two peers has transmitted a
Goodbye Message
The goodbye message is a feature designed to improve EIGRP network convergence. The goodbye message
is broadcast when an EIGRP routing process is shut down to inform adjacent peers about the impending
topology change. This feature allows supporting EIGRP peers to synchronize and recalculate neighbor
relationships more efficiently than would occur if the peers discovered the topology change after the hold
timer expired.
The following message is displayed by routers that run a supported release when a goodbye message is
received:
RP/0//CPU0:Mar 13 09:13:17:eigrp[163]:%ROUTING-EIGRP-5-NBRCHANGE: IP-EIGRP(0) 1: Neighbor
10.0.0.20 (GigabitEthernet0/6/0/0) is down: Interface Goodbye received
A Cisco router that runs a software release that does not support the goodbye message can misinterpret the
message as a K-value mismatch and display the following message:
RP/0//CPU0:Mar 13 09:13:17:eigrp[163]:%ROUTING-EIGRP-5-NBRCHANGE: IP-EIGRP(0) 1: Neighbor
10.0.0.20 (GigabitEthernet0/6/0/0) is down: K-value mismatch
Note
The receipt of a goodbye message by a nonsupporting peer does not disrupt normal network operation. The
nonsupporting peer terminates the session when the hold timer expires. The sending and receiving routers
reconverge normally after the sender reloads.

Percentage of Link Bandwidth Used for EIGRP Packets

By default, EIGRP packets consume a maximum of 50 percent of the link bandwidth, as configured with the
bandwidth interface configuration command. You might want to change that value if a different level of link
utilization is required or if the configured bandwidth does not match the actual link bandwidth (it may have
been configured to influence route metric calculations).

Floating Summary Routes for an EIGRP Process

You can also use a floating summary route when configuring the summary-address command. The floating
summary route is created by applying a default route and administrative distance at the interface level. The
following scenario illustrates the behavior of this enhancement.
Figure 11: Floating Summary Route Is Applied to Router-B, on page 185
Router-A, Router-B, and Router-C. Router-A learns a default route from elsewhere in the network and then
Routing Configuration Guide for Cisco NCS 6000 Series Routers, IOS XR Release 6.4.x
184
router eigrp 100
interface GigabitEthernet0/6/0/1
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.
"goodbye" message and the receiving router does not support this message. In this case, the receiving
router interprets this message as a K-value mismatch.
Implementing EIGRP
shows a network with three routers,