QoS routing using alternate paths |
| Adrian Segall, Pravin Bhagwat, Arvind Krishna |
| A QoS routing protocol based on alternative path selection is described.
Using a combination of source routing and shortest path routing, packets
are routed along alternate paths when available resources along the shortest
path cannot satisfy the QoS requirements of end to end flows. For
path selection, the QoS routing protocol makes use of the information already
available in the OSPF link information database. Packet forwarding
uses existing mechanisms within the Internet protocols. Thus, support for
QoS routing is provided without requiring major changes to the existing
installed base of OSPF routers. Our proposal provides QoS routes for unicast
as well as multicast connections. The major virtues of the solution
are that of providing an evolutionary approach, whereby only a subset of
the routers need to be enabled, and that the additional algorithms are
computationally simple without requiring state maintenance at every router.
Simulations of our proposed routing protocols on the UUnet backbone show
that they perform well, almost optimal in terms of delivering the desired
QoS for end to end flows.
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| Paper (gzipped postscript) |
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