Enhancing label space usage for Ethernet VLAN-label switching

Ethernet is positioning itself as an aggregation technology for carrier transport networks; however, as it was designed for local area networks, native bridged Ethernet does not fulfill all carrier requirements. Ethernet VLAN-label switching (ELS) has been designed to make Ethernet fulfill carrier requirements. ELS allows the creation of label switched data paths using a 12-bit label encoded in the VLAN TAG control information field. As previous label switching technologies use more bits to encode the label, they do not suffer from the label sparsity issues that ELS might. This paper studies the label sparsity issues resulting from the reduced ELS VLAN-label space. For this purpose the applicability of existing techniques for enhancing label space is studied and evaluated in the online routing scenario. Novel routing schemes are also proposed for taking advantage of the available techniques in order to further enhance the ELS VLAN-label space.