v The LSP bandwidth parameters are policed at
the LSP ingress in the edge node. Actions to
be taken (drop or re-colouring) are part of the
configuration of the nodes.
vi In an operational network the LSP parameters
must be dynamically updated based on traffic
measurements. This is at least necessary for
traffic for which bandwidth is not reserved
end-to-end. Thresholds must be defined for
such updating.
Conclusions
Lack of traffic control in IP networks makes it
very difficult, if at all possible, to offer differen-
tiated services with some kind of performance
guarantee. A control framework has been pro-
posed. This framework is based on the use of
the Differentiated Services architecture, Multi
Protocol Label Switching, monitoring of Label
Switched Path traffic volume and dynamically
updating of bandwidth reservations based on
actual traffic.
The deployment of the proposed solution de-
pends however on cost related to implementing
monitoring hardware in the edge routers and
possible technology constraints related to moni-
toring at high speed. Also it remains to be seen
what service differentiations are possible to
achieve in this type of network.
The framework should be extended to treat inter-
domain aspects and the use of e.g. IntServ in the
access part of the network. Also related aspects
like
- Use of load sharing;
- Criteria for creation and termination of LSPs;
- Criteria for triggering a re-configuration of the
MPLS network, involving routing; - Use of back-up paths and pre-emption
should be included in the framework.
References
[diffserv-new-terms] IETF. 2001. New Termi-
nology for Diffserv. (draft-ietf-diffserv-new-
terms-04.txt)[diffserv-pdb-def] IETF. 2001. Definition of Dif-
ferentiated Services Per Domain Behaviours and
Rules for their Specification. (RFC 3086)[IETF-TE] IETF. 2001. A Framework for Inter-
net Traffic Engineering. (draft-ietf-tewg-frame-
work-05.txt)[Johnsen1999] Johnson, V. 1999. Technology
Backgrounder – Quality of Service – Glossary of
Terms. [online] – URL: http://www.stardust.com.[mpls-diff-ext] IETF. 2001. MPLS support for
Differentiated Services. (draft-ietf-mpls-diff-ext-
09.txt)[RFC1633] IETF. 1994. Integrated Services in
the Internet Architecture: an Overview. (RFC
1633)[RFC2474] IETF. 1998. Definition of the Differ-
entiated Services Field (DS Field) in the IPv4
and IPv6 Headers. (RFC 2474)[RFC2475] IETF. 1998. An Architecture for Dif-
ferentiated Services. (RFC 2475)[RFC2597] IETF. 1999. A Single Rate Three
Color Marker. (RFC 2697)[RFC2598] IETF. 1999. An Expedited Forward-
ing PHB. (RFC 2598)[RFC3031] IETF. 2001. Multiprotocol Label
Switching Architecture. (RFC 3031)