Welcome to DAS-3 Page

	distributed ASCI supercomputer: DAS-3
	The next generation Grid infrastructure in the Netherlands

Architecture

Wide-area Connectivity

An important issue within the DAS-3 project is the wide-area communications infrastructure between the clusters. Each cluster will have 1Gbps of connectivity to the regular Internet through its local University and then on to SURFnet. To satisfy higher demands in bandwidth, transparency and latency however, the StarPlane project collaborates with SURFnet to enable DAS-3 to use dedicated 10Gbps lightpaths across SURFnet's DWDM backbone between clusters. The following picture shows an overview of network connections between clusters via the SURFnet6 Common Photonic Layer (CPL) network infrastructure, which is one of the first production example in the world of a hybrid network.

Cluster Architecture

Each cluster of DAS-3 is comprised of a series of computing nodes and a head node. The number of computing nodes depends on the location varying from a minimum of 32 to a maximum of 85. The connectivity of each cluster is shown in the following figure. There is a so-called LAN connection to the local university and a WAN connection to SURFnet.

Both the head node and the cluster nodes connect to the LAN with Ethernet interfaces: 1 GE for the cluster nodes and 10GE for the head node. The Ethernet switches used for this connection are stackable Nortel 5530s and 5510s. For our research on StarPlane we are particularly interested in the WAN connectivity to the SURFnet6 CPL network, which allows the creation of lightpaths through the optical infrastructure. The WAN connections, as shown in the drawing, go via a Myrinet switch. Both the head node and the cluster nodes use 10 Gbit/s connections on NIC set to operate in Myrinet mode. The Myrinet switch itself has 8 10GE connections to SURFnet, and more specifically to a Nortel OME 6500. These connections are on a new Ethernet card being developed by Myrinet that should be delivered soon.

Using the WAN connections to CPL the DAS-3 cluster nodes will participate in StarPlane. Applications running on the cluster will contact the management plane to request a suitable network path through SURFnet6. The StarPlane control plane will configure both the network portion in the DAS-3 domain, such as the Myrinet switches, and negotiate the path with the CPL components on SURFnet6.

Related Links
	DAS website at VU: >>view
	DAS page at Gigaport project: >>view
	StarPlane project: >>view
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