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. |