This paper describes the DUAL (diffusion update algorithm), which is used in Cisco’s EIGRP. The algorithm guarantees loop-free routing at any time by imposing a constraint (feasibility condition) on route update. The feasibility condition is a conservative condition in the sense that it rejects some legitimate route update so that loops can be totally avoided.

## Bibliographic data

@article{
title = "Loop-Free Routing Using Diffusing Computations",
author = "J. J. Garcia-Lunes-Aceves",
journal = "IEEE/ACM Trans on Networking",
volume = "1",
number = "1",
pages = "130--141",
month = "Feb",
year = "1993",
}