Multipath routing for eVLB

Sergio K. Sobarzo and S.N Torres


The very long baseline interferometry (VLBI) technique currently demands data storage resources of about 2 TBytes per day which must be analyzed in correlation centers. The current process involves the physical storing and shipping of magnetic disks to these centers, where up to 5 days are needed for transportation. The need of a fast turnaround opened a new research line where all the collected data of observing radiotelescope stations is sent over the Internet. This technique is called eVLBI. Ideally the station is part of a National Research and Education Network (NREN) where multiple intercontinental routes are available. Under this scenario a new protocol has been developed which allows multiple parallel data flows with important throughput improvements. The unique properties of VLBI data imply the development of a custom load control based on user datagram protocol (UDP). A description of the new protocol and performance comparisons of the first demonstrations for eVLBI performed at the Transportable Integrated Geodetic Observatory (TIGO) are included in the present article.