MESCAL has designed several solution options that target different customers categories, one of which is a solution suitable for enterprise customers and mission critical applications that require strong guarantees in terms of traffic QoS treatment and available bandwidth. This category of application requires also strong security and traffic isolation. For this business target, MESCAL designed the Path Computation System that is responsible for finding an inter-domain path satisfying a set of QoS performance guarantees and then for establishing inter-domain constraint-based LSPs.

MESCAL proposed a scheme in which the computation of this path is distributed. Communication between PCS entities is achieved via the inter PCE Communication Protocol (PCP), designed by the MESCAL project. Once computed, the path established by the RSVP-TE/MPLS machinery of the head-end Label Switching Router, which establishes an inter-domain Label Switching Path that follows the inter-domain path provided by the PCS.

MESCAL suggested also a mechanism for discovering remote ASes that support the Hard Guarantees Solution Option. This mechanism consists in attaching a Path Computation Service Identifier to each AS that supports the HGSO. This identifier is then announced in q-BGP. This announcement is identified by a well know community value. Thanks to this specific announcement, remote PCS can discovers the path to reach a given AS supporting the HGSO.

The solution improves the overall security level of the service while reducing the amount of q-BGP announcements and the size of the routing information bases because it does not require that the head-end and tail-end addresses of the LSPs are announced and propagated across the Internet.

Further reading:

M. Boucadair, P. Morand (Eds.), "Inter PCE Communication protocol", draft-boucadair-pce-comm-proto-00.txt, Work in Progress, May 2005. [link]

M. Boucadair, P. Morand (Eds.), "A Solution for providing inter-AS MPLS-based QoS tunnels", draft-boucadair-pce-interas-01.txt, Work in Progress, May 2005. [link]

M. Boucadair, P. Morand (Eds.), "Path Computation Service discovery via Border Gateway Protocol", draft-boucadair-pce-discovery-01.txt, Work in Progress, May 2005. [link]

MESCAL deliverable D1.3, "Final specification of protocols and algorithms for inter-domain SLS management and traffic engineering for QoS-based IP service delivery", Chapter 10, section 10.5.2. [link]

MESCAL deliverable D3.2, "Final experimental results: validation and performance assessment of algorithms and protocols for inter-domain QoS through service-driven traffic engineering", Chapter 4, section 4.4. [link]

PCS demonstration: avi movie file of screenshots of the path computation system in action in the MESCAL testbed. [pcs-demo.avi]. Note that this is a 100 MB file and it requires the TechSmith Screen Capture Codec.