Kirill Levchenko Geoffrey M. Voelker Ramamohan Paturi Stefan Savage Xl: an efficient network routing algorithm. 15-26 2008 SIGCOMM http://doi.acm.org/10.1145/1402958.1402962 conf/sigcomm/2008 db/conf/sigcomm/sigcomm2008.html#LevchenkoVPS08