Speaker
Artur Barczyk
(Caltech)
Description
Most of today's data networks are a mixture of packet switched and circuit switched
technologies, with Ethernet/IP on the campus and in data centers, and SONET/SDH over
the wide area infrastructure.
SONET/SDH allows creating dedicated circuits with bandwidth guarantees along the
path, suitable for the use of aggressive transport protocols optimised for fast data
transfer and without fairness constraints. On the downside, a provisioned, but
under-utilised circuit may result in poor overall network utilisation, as the
reserved bandwidth cannot be used by another flow. Addressing this issue, Virtual
Concatenation (VCAT) and Link Capacity Adjustment Scheme (LCAS) are recent addition
to SONET/SDH, and allow dynamic creation and hitless bandwidth adjustment of virtual
circuits.
Caltech and CERN have deployed optical multiplexing equipment supporting VCAT/LCAS on
their US LHCNet transatlantic network, and agent-based grid and network monitoring
software based on Caltech's MonALISA system, to provide on-demand end-to-end
bandwidth guarantees for data transfers between Tier-N centres, following the GLIF
concept for control plane interaction between the participating networks.
This is being coordinated with the LHC experiments' management software for dataset
distribution, and with the circuit segment-provisioning developments of ESnet,
Internet2, Fermilab, BNL, GEANT2 and collaborators to form the end-to-end network
paths. MonALISA is used to oversee the progress, troubleshoot and mitigate problems
associated with dynamic provisioning in response to multiple transfer requests.
We present our experience with operating VCAT/LCAS enabled network for transatlantic
connections, along with the details of a first implementation of circuit oriented
end-to-end services for data transfers between data centres.
Primary authors
Artur Barczyk
(Caltech)
Dan Nae
(Caltech)
Harvey Newman
(Caltech)
Iosif Legrand
(Caltech)
Sylvain Ravot
(Caltech)
Yang Xia
(Caltech)
