Background

As part of the observatory project to upgrade the correlator, an assessment has been requested to different groups in the observatory that are affected or that they would need to provide improvements to their products in order to be compatible with the proposed upgrades. In particular ACS will analyze the existing infrastructure and software to allow bulk data transfer to satisfy a higher throughput than what is currently needed and what efforts would be required to go beyond the current capabilities.

Infrastructure

The existing infrastructure consists of 10 Gbps equipment including, Ethernet cards, switches and cables. In specific cases, the connection between some servers is handled by Cisco's fabric interconnect which has a throughput capacity of 10+ Gbps.

Empirical Analysis

An empirical analysis was performed over the network using three approaches focused on see the current performance of our existing implementation of the bulk data transfer system.

• We analyzed the network throughput and latencies using IPerf
• We analyzed the throughput over the same network using bulk data transfer system's underlying technology, RTI DDS
• We analyzed the throughput over the same network using the bulk data transfer system

All the details of this analysis can be found at:  Unable to locate Jira server for this macro. It may be due to Application Link configuration.

IPerf Network Analysis (10 Gbps link)

• TCP and UDP unicast used only one receiver
• The UDP protocol used is unreliable and is prone to datagram losses

RTI DDS Network Analysis (10 Gbps link)

• Problems with TCP implementation of RTI DDS demo
• UDP unicast used only one receiver
• Sender information is the maximum latency identified during the transfers
• UDP uses a reliable protocol

BulkDataNT Network Analysis (10 Gbps link)

• TCP and UDP unicast used only one receiver
• Sender identifies the slowest speed among its receivers
• UDP uses a reliable protocol

Executive Summary