In order to prevent Enhanced Interior Gateway Routing Protocol (EIGRP) updates from overwhelming the interface, Cisco IOS provides controls how much bandwidth it can consume on the physical interface. By default, EIGRP limits itself to using no more than 50 percent of the interface bandwidth. Although, this is not very significance on high speeds like Ethernet, it becomes critical on low speed links.
Sometimes the interface bandwidth configuration cannot be changed because of routing policy considerations, or for any other reason, in that case bandwidth-percent command should be used to control the EIGRP bandwidth. On low-speed interfaces, raising the available bandwidth for EIGRP above the default of 50 percent is advisable in order to improve convergence.
ip bandwidth-percent eigrp
ip bandwidth-percent eigrp 100 25