2 research outputs found
Fast and Efficient Bulk Multicasting over Dedicated Inter-Datacenter Networks
Several organizations have built multiple datacenters connected via dedicated
wide area networks over which large inter-datacenter transfers take place. This
includes tremendous volumes of bulk multicast traffic generated as a result of
data and content replication. Although one can perform these transfers using a
single multicast forwarding tree, that can lead to poor performance as the
slowest receiver on each tree dictates the completion time for all receivers.
Using multiple trees per transfer each connected to a subset of receivers
alleviates this concern. The choice of multicast trees also determines the
total bandwidth usage. To further improve the performance, bandwidth over
dedicated inter-datacenter networks can be carved for different multicast trees
over specific time periods to avoid congestion and minimize the average
receiver completion times.
In this paper, we break this problem into the three sub-problems of
partitioning, tree selection, and rate allocation. We present an algorithm
called QuickCast which is computationally fast and allows us to significantly
speed up multiple receivers per bulk multicast transfer with control over extra
bandwidth consumption. We evaluate QuickCast against a variety of synthetic and
real traffic patterns as well as real WAN topologies. Compared to performing
bulk multicast transfers as separate unicast transfers, QuickCast achieves up
to reduction in mean completion times while at the same time using
the bandwidth. Also, QuickCast allows the top of receivers
to complete between to faster on average compared with
when a single forwarding multicast tree is used for data delivery
Efficient Inter-Datacenter Bulk Transfers with Mixed Completion Time Objectives
Bulk transfers from one to multiple datacenters can have many different
completion time objectives ranging from quickly replicating some copies to
minimizing the time by which the last destination receives a full replica. We
design an SDN-style wide-area traffic scheduler that optimizes different
completion time objectives for various requests. The scheduler builds, for each
bulk transfer, one or more multicast forwarding trees which preferentially use
lightly loaded network links. Multiple multicast trees are used per bulk
transfer to insulate destinations that have higher available bandwidth and can
hence finish quickly from congested destinations. These decisions--how many
trees to construct and which receivers to serve using a given tree--result from
an optimization problem that minimizes a weighted sum of transfers' completion
time objectives and their bandwidth consumption. Results from simulations and
emulations on Mininet show that our scheduler, Iris, can improve different
completion time objectives by about .Comment: Accepted to Elsevier Computer Network