35 research outputs found
Fairness for ABR multipoint-to-point connections
In multipoint-to-point connections, the traffic at the root (destination) is
the combination of all traffic originating at the leaves. A crucial concern in
the case of multiple senders is how to define fairness within a multicast group
and among groups and point-to-point connections. Fairness definition can be
complicated since the multipoint connection can have the same identifier
(VPI/VCI) on each link, and senders might not be distinguishable in this case.
Many rate allocation algorithms implicitly assume that there is only one sender
in each VC, which does not hold for multipoint-to-point cases. We give various
possibilities for defining fairness for multipoint connections, and show the
tradeoffs involved. In addition, we show that ATM bandwidth allocation
algorithms need to be adapted to give fair allocations for multipoint-to-point
connections.Comment: Proceedings of SPIE 98, November 199
Performance of Bursty World Wide Web (WWW) Sources over ABR
We model World Wide Web (WWW) servers and clients running over an ATM network
using the ABR (available bit rate) service. The WWW servers are modeled using a
variant of the SPECweb96 benchmark, while the WWW clients are based on a model
by Mah. The traffic generated by this application is typically bursty, i.e., it
has active and idle periods in transmission. A timeout occurs after given
amount of idle period. During idle period the underlying TCP congestion windows
remain open until a timeout expires. These open windows may be used to send
data in a burst when the application becomes active again. This raises the
possibility of large switch queues if the source rates are not controlled by
ABR. We study this problem and show that ABR scales well with a large number of
bursty TCP sources in the system.Comment: Submitted to WebNet `97, Toronto, November 9
Feedback Consolidation Algorithms for ABR Point-to-Multipoint Connections in ATM Networks
ABR traffic management for point-to-multipoint connections controls the
source rate to the minimum rate supported by all the branches of the multicast
tree. A number of algorithms have been developed for extending ABR congestion
avoidance algorithms to perform feedback consolidation at the branch points.
This paper discusses various design options and implementation alternatives for
the consolidation algorithms, and proposes a number of new algorithms. The
performance of the proposed algorithms and the previous algorithms is compared
under a variety of conditions. Results indicate that the algorithms we propose
eliminate the consolidation noise (caused if the feedback is returned before
all branches respond), while exhibiting a fast transient response.Comment: Proceedings of IEEE INFOCOM 1998, March 1998, volume 3, pp. 1004-101
A Definition of General Weighted Fairness and its Support in Explicit Rate Switch Algorithms
In this paper we give a general definition of weighted fairness and show how
this can achieve various fairness definitions, such as those mentioned in the
ATM Forum TM 4.0 Specifications. We discuss how a pricing policy can be mapped
to general weighted (GW) fairness. The GW fairness can be achieved by
calculating the (weighted fairshare of the left over
bandwidth) for each VC. We show how a switch algorithm can be modified to
support the GW fairness by using the . We use ERICA+ as an
example switch algorithm and show how it can be modified to achieve the general
fairness. Simulations results are presented to demonstrate that the modified
switch algorithm achieves GW fairness. An analytical proof for convergence of
the modified ERICA+ algorithm is given in the appendix.Comment: Proceedings of ICNP'98, October199