Using MAC addresses as efficient routing labels in data centers

Abstract

A number of new technologies such as cloud services and/or virtualization have changed data center networks in the last few years. The benefits of the techniques are clear but the downside is that more forwarding entries are needed in network switches to support these techniques. Unfortunately, the number of forwarding entries in switches have a hard limit. We give a formal problem definition for minimizing the number of forwarding entries and a proof that the problem is NP complete. We show that the destination MAC address can be used as a universal label in software-defined networks and the ARP caches of hosts can exploited as an ingress label table, reducing the size of the forwarding tables of network devices. We have the additional advantage of not requiring a special type of data center network or additional hardware capabilities. We demonstrate that our technique can solve the problem of FIB sizes by introducing a greedy scheme for all pairs ECMP with a minimal number of FIB entries.