摘要：The QoS provided by today’s best effort Internet is not good enough for real-time
premium traffic (PT). It is believed that QoS guarantees could be better provided by the
connection oriented networks such as MPLS. However, these connection oriented
networks are inherently more prone to network failures. Failures of connection oriented
networks can be broadly classified into two types namely: link/path failures and
degraded failures. Degraded failures that account for about 50% of total failures are
mostly detected by control plane timers. The control plane and the data plane of
connection oriented networks such as MPLS are logically separated and therefore a
failure in the control plane should not always disconnect the communications in the data
plane. The Virtual Path Hopping (VPH) concept in this study distinguishes these two
types of failures and avoids the disconnections of communications in the data plane due
to degraded failures. The computer simulations performed and the results are presented
to support the concept. The Dynamic Virtual Path Allocation (DVPA) algorithm to
improve the availability of the connection oriented backbone networks without
compromising the network resource utilization efficiency is also discussed here. DVPA is
to achieve very fast re-routing for link/path failures. Therefore the connection oriented
architecture with VPH and DVPA could provide QoS guarantees and high availability
for real-time applications over the Internet.
