Label space reduction in MPLS networks: how much can a single stacked label do?

Most network operators have considered reducing LSR label spaces (number of labels used) as a way of simplifying management of underlaying Virtual Private Networks (VPNs) and therefore reducing operational expenditure (OPEX). The IETF outlined the label merging feature in MPLS--allowing the configuration of MultiPoint-to-Point connections (MP2P)--as a means of reducing label space in LSRs. We found two main drawbacks in this label space reduction scheme: ) it should be separately applied to a set of LSPs with the same egress LSR--which decreases the options for better reductions, and ) LSRs close to the edge of the network experience a greater label space reduction than those close to the core. The later implies that MP2P connections reduce the number of labels asymmetrically. In this article we propose a solution to these drawbacks achieved by stacking an additional label onto the packet header. We call this type of reduction Asymmetric Merged Tunnels (AMT). A fast framework for compu...

• Type: Journal
• Year: 2008
• Where: TON
• Authors: Fernando Solano, Thomas Stidsen, Ramón Fabregat, José-Luis Marzo
• Keywords: Label, Label Space, Label Space Reduction, TON 2008