Cornell Theory Center (CTC)
National Center for Atmospheric Research (NCAR)
National Center for Supercomputing Applications (NCSA)
Pittsburgh Supercomputing Center (PSC)
San Diego Supercomputer Center (SDSC)
The technical and engineering support was related to establishing and extending vBNS connectivity, performance testing, and troubleshooting. MCI's 2nd quarter 1995 (April to June) report on the vBNS provides generally a more detailed description of the first quarter vBNS deployment.
In the outreach, coordination and management role, NLANR focused on developing and refining procedures to facilitate access to vBNS resources by the research community. NLANR has also established several working groups to focus on dual-natured research areas, in that they involve research themselves but also will provide infrastructural support for other research on the vBNS. These areas include multicast, multimedia conferencing tools, collaborative environments, advanced routing functionality, security, middleware, TCP performance analysis, statistics monitoring. We also highlight current vBNS applications based at NLANR sites.
As part of the initial testing of vBNS connectivity, sites set up IP network routes to exchange traffic between the shared FDDI rings at their site and the other vBNS sites. Initial testing showed all network components in the path (Cisco routers, Lightstream 20/20 ATM switches and GDC ATM switches) performing as expected and operating reliably.
The NetStar GigaRouters continue to exhibit unstable behavior, with the HIPPI interfaces frequently locking up. We were able, though, to establish a HIPPI to HIPPI path over the vBNS, and exchanged TCP/IP traffic between HIPPI attached machines at SDSC and PSC. We provided test results and feedback to MCI and to NetStar to help them fix problems. Steve Cunningham (PSC) assisted MCI with site planning for the installation of the vBNS and the testnet, and assisted vBNS users in the deployment of vBNS attached hardware at the Westinghouse Energy Center.
HIPPI-to-HIPPI tests indicated that performance was severely limited by the NetStar GigaRouters. Using large packets (approximately 8 kbyte) allowed 100 Mbps throughput between two Cray computers (between SDSC and PSC), but the NetStar HIPPI interface does not perform well for large packets-per-second traffic loads, so smaller packets limit end-to-end performance of applications that use them. We continue to test both configurations and performance in the presence of resource contention.
NCSA ran a test in June between supercomputers at NCSA and SDSC, measuring performance as below.
| Buffer size | Avg Sys Time | Avg Usr Time | Avg Mb/s | Peak Mb/s |
|---|---|---|---|---|
| 1K | 48.76% | 1.84% | 25.4 | 40.9 |
| 2K | 26.96% | 1.16% | 31.4 | 51.1 |
| 4K | 19.84% | 0.82% | 42.0 | 51.3 |
| 7K | 13.36% | 0.44% | 37.7 | 51.6 |
| 8K | 8.20% | 0.42% | 40.1 | 51.6 |
| 15K | 5.96% | 0.28% | 32.8 | 48.0 |
| 16K | 6.68% | 0.30% | 36.5 | 51.6 |
| 31K | 4.48% | 0.12% | 26.3 | 51.6 |
| 32K | 8.80% | 0.20% | 51.0 | 51.7 |
| 48K | 8.34% | 0.10% | 50.8 | 51.8 |
| 57K | 6.84% | 0.10% | 41.3 | 51.8 |
| 60K | 7.44% | 0.10% | 46.0 | 51.8 |
| 63K | 6.80% | 0.10% | 42.8 | 47.5 |
| 64K | 5.16% | 0.08% | 32.7 | 51.2 |
| 128K | 8.26% | 0.10% | 51.7 | 51.8 |
| Buffer size | Avg Sys Time | Avg Usr Time | Avg Mb/s | Peak Mb/s |
|---|---|---|---|---|
| 1K | 13.04% | 1.22% | 16.2 | 30.2 |
| 2K | 17.54% | 1.14% | 26.6 | 50.2 |
| 4K | 21.62% | 1.12% | 39.1 | 49.7 |
| 7K | 17.30% | 0.82% | 33.3 | 50.5 |
| 8K | 18.54% | 0.76% | 36.6 | 50.3 |
| 15K | 19.60% | 0.78% | 34.7 | 47.3 |
| 16K | 17.62% | 0.66% | 30.3 | 49.4 |
| 31K | 16.82% | 0.60% | 29.5 | 47.8 |
| 32K | 27.28% | 0.92% | 48.3 | 49.7 |
| 48K | 28.32% | 0.88% | 47.7 | 49.4 |
| 57K | 23.66% | 0.72% | 41.5 | 50.1 |
| 60K | 25.24% | 0.76% | 43.7 | 49.6 |
| 63K | 24.36% | 0.78% | 41.9 | 49.9 |
| 64K | 23.64% | 0.70% | 38.9 | 49.3 |
| 128K | 28.58% | 0.80% | 49.9 | 50.3 |
nettest log: Tue Jun 13 11:30:27 CDT 1995 nettest command: nettest -l -b 768k total data: 62914560 repetitions: 5 socket buffer size: 768k data file: sif.to.c90-HIPPI.sdsc.edu.130695.113027 dedicated: no tcp mss: 8948 average load on local host: 0.72 average load on remote host: -1.00
Cornell has connected and configured IP over HIPPI to the SP2, and tested performance with Matt Mathis to the Cray at PSC. NCSA and Cornell have also used HIPPI-attached Power Challenges at each site for the Seidel gravitational field calculation application, described later, and are beginning testing for that application between Cornell's SP2 and the SGI Power Challenge Array at NCSA.
Cornell connected their campus FORE-based network to the vBNS Lightstream with an upgrade of the FORE ASX-200 switch software to version 3.4. They also connected their IPOP machine via 155 Mbps ATM interface to this FORE switch and successfully tested IP connectivity across the vBNS, as well as testing PVC-based IP connectivity from NYNET through this FORE switch to the vBNS.
NLANR maintains a public record of all such uses (In the event of a disagreement between members of the vTCC as to whether or not a proposed use falls within the parameters of the delegation, the issue will be escalated to the NSF Program Official). NSF expects this delegation will facilitate vBNS use for performance testing of both the network itself and for applications and technologies not specifically reviewed for merit. vBNS utilization authorized under this delegation may decline as NSF-approved connections and applications on the vBNS increase and will not impede the use of the vBNS by such NSF authorized connections and applications.
K. Claffy of SDSC serves as NLANR Research Coordinator to facilitate collaboration and outreach. Claffy established a publicly web-accessible database of applications that are either active on the vBNS or under review by the vBNS Technical Coordination Committee based on information in their allocation request form.
Jamshid Mahdavi of PSC serves as co-chair (with Rick Wilder of MCI)
of the vBNS Technical Coordination Committee, and provides
web-accessible versions of the
The Principal Investigators at each site
(Douglas S. Carlson,
Marla Meehl,
Randal L. Butler,
Matthew Mathis,
and Bilal A. Chinoy
at
CTC,
NCAR,
NCSA,
PSC,
and SDSC, respectively),
and a second representative from each site
(Paul Hyder,
Phil Pishioneri,
Paul Zawada,
K. Claffy,
Jamshid Mahdavi),
have acted both as members of the vTCC and as engineering
support for new applications as they come online.
These site contacts provide support for establishing
application-specific routing and configuring both local site resources
and the vBNS backbone as required to support new applications. In
particular, technical staff have spent considerable time helping vBNS
`friendly users' with vBNS/I-WAY projects
for the Supercomputing'95 conference,
including tasks such as I-POP scheduling, route setup, and testing over
the vBNS.
A useful example is the efficient support for multiple
qualities of service, which vendors are not commonly building
into their equipment. Understandably so, since their customers,
ISPs, are not asking for it (or certainly not very loudly),
perhaps partly due to an established mindset
that ``the Internet does not support it.''
The vBNS provides an opportunity to push the vBNS-supplying
vendors, which others will no doubt follow,
into offering this kind of support, since it will
prevent larger scale development efforts for service
guarantees from being in the critical path of moderate
scale improvements to the infrastructure.
Indeed, we view the commodity
Internet infrastructure as rapidly approaching a dangerous time period,
where congestion will overwhelm many service providers before equipment
vendors have full-scale quality of service and admission control
mechanisms in place.
We believe the vBNS can play a critical role, not only with its
lead in technology, but also in its unique position within the Internet
community as a neutral and multi-site testing ground for proposed
changes, whether in the form of completely new algorithms or
modifications to existing algorithms. For example, the NSF can help by
encouraging the vBNS to demonstrate a prototype system using existing
functionality, e.g,. the IP precedence field, to implement a
small range of service qualities on the vBNS.
Multicast support
(leads: kc@nlanr.net and
kthomp@mci.net )
Each NLANR site has set up a multicast router, in most cases in
addition to the existing multicast router at the site, in order to
support high-bandwidth multicast experiments on the vBNS without
interfering with operational Mbone traffic. Most sites were initially
using SGI Indigos purchased for a previous multi-center project. MCI
has since decided to deploy the most recent version of mrouted
(3.6) on the Digital alphas in each vBNS node. (PSC did not set up
the Indigo but preferred to wait for this Alpha support.) Some sites, at
least SDSC and Cornell, will continue to use the Indigo additionally in
order to develop and maintain CU-SeeMe reflectors to nv/vat client
gateways.
David Mitchell at NCSA provided operational Mbone support at NCSA via
the SGI probe system running mroutedv 3.4 for several months, then
converted to a Sun OS Sparc5 running mrouted v3.6. Once a Solaris
version is available and tested, NCSA will convert again, in parallel
with MCI's Mbone support on the Alphas. This redundancy will be useful at
times, including for multi-platform interoperability.
NSF has approved the vBNS for preemptible use
for tunnels to connect to the standard Mbone, and NLANR will begin
coordinating with the Mbone community in deploying those tunnels.
Network based multimedia
collaboration tools (lead: jeffwink@sdsc.edu)
Jeff Winkler (SDSC) has
taken a lead in the
coordination of a cross-platform, cross-site interoperability
effort for multimedia collaboration tools, including coordinating
an infrastructure that can provide the functionality of the
circuit-based videoteleconferencing room facilities that the sites were
using until 1 December 1995 when they were dismantled.
NLANR is coordinating resources to replace the facilities
to meet intercenter virtual meeting needs.
Perhaps the most difficult aspect of getting the EMMI's configured has
been getting the drivers to install properly. AT&T seems to think the
problem lies in our using the SUN IPC machines rather than a Sparc
station. We currently are using a SUN IPC.
So far we have tested the EMMI in the following configurations: a
local loop back, local back-to-back, loop back through our ASX-200
switch, and across the vBNS to SDSC using 3 VCs. In each case, we have
sent an audio and video feed. We have not had sufficient equipment to
test the video conferencing software yet.
Despite not having any quantitative measurements, we can make
a qualitative assessment of the EMMI's performance. With both EMMI's
set at a Q factor of 25 (approximately 14 Mbps), the images received on
both ends are smooth and free of jitter. Audio is also smooth and free
of distortion. However, there seem to be some difficulties with the
EMMI asking for more bandwidth than we can deliver, especially as we
increase the Q-factor.
Currently, there is a lot of hands-on maintenance and babysitting in
order to keep the EMMI's functioning properly. System log files fill
quickly if there is a communication failure. The user interface
frequently wedges the machine, and the video conferencing software is
not very tolerant. It seems that if the EMMI is on a Sparc station,
overall management is much easier. We have worked closely with the
technical staff at AT&T to identify software bugs
and expect a new release that resolves these problems soon.
Currently we are running tests between NCSA and SDSC. We have been
offered a third unit and are talking to PSC as a possible site to host
it. This would allow us a more realistic test of an actual conference
system. In addition we plan to bring up the whiteboard capabilities in
early December. We expect the project to be complete by the end of
1995. Butler (NCSA) also expects to submit a proposal soon in
collaboration with an Industrial Partner that is interested in
using MPEG transfers for live video clips on the air. They expect
these live feeds to come from sites all over the country and would like
to use the vBNS as a testbed to research real-time transfer of MPEG
streams over a wide area ATM network.
Collaborative environments
(lead: bbj1@cornell.edu )
Bruce Johnson (Cornell) has
recently begun to lead efforts to integrate existing technology on
text-based collaboration environments and multimedia tools such as
CU-SeeMe. Jeff Winkler (SDSC) and Scott Brim (Cornell) expect to
investigate integrating an active MOO environment with CU-SeeMe, and
explore the differences between such an approach and other
existing architectures (e.g., Juptier at Xerox Parc).
Network routing
(leads: mahdavi@psc.edu
and jjamison@mci.net)
As detailed in MCI's
quarterly report, dynamic routing occurs between all vBNS sites,
using OSPF among vBNS routers. The four NSF-supported NAPs are
connected to the vBNS via DS-3 circuits, and MCI will utilize BGP4
peers with other Internet Service Providers as soon as non-SCC users
for the vBNS are identified and approved by the NSF. MCI has
established BGP4 peering between the vBNS and MCI's commercial IP
network at three of the NAPs to test the NAP connections and import
routes needed for network management access to the vBNS equipment.
Routing at the ATM level is static, facilitating reliability and
predictability of routing. ATM switch configuration includes an
over-full mesh of permanent virtual circuits among vBNS routers; each
router knows about virtual circuits used for optimal `one-hop' paths to
peer vBNS routers. In addition, where appropriate, they are configured
to use other `secondary' virtual circuits to maintain connectivity in
the event of circuit or switch failures in the ATM backbone. In some
cases fall-back routes use an alternative VC through the backbone and
maintain single-hop connectivity; in other cases the secondary route
uses an additional router hop.
For IP level routing configuration, vBNS users can send route
specifications directly to MCI engineering or may use the automated MCI
vBNS route registry.
Network policy routing
(lead: kc@nlanr.net)
Mathis (PSC) has provided several initial drafts of views for routing
plans for the vBNS architecture that attempt to satisfy the constraints
of a high performance, research, non-production network with the needs
of the end-sites and the continual change that occurs in a developing
network.
In order to deal with vBNS routing requirements of host routes and
variable length subnets, Paul Zawada of NCSA configured OSPF in the
NCSA LAN, and also configured a route server (Sun sparc) that utilizes
gated and supplies routes to the internal NSC routers running OSPF.
Experimental router development
(lead: csong@mci.net)
Researchers will also likely want to experiment with new IP
functionality on the vBNS. MCI has discussed feasibility of doing this
with NetStar, one of the current vBNS router vendors. NetStar has
indicated its desire to support router experimentation on the vBNS and
MCI drafted a proposed a software specification to allow experimental
software to be written by MCI and incorporated into the vBNS NetStar
GigaRouters. The proposed interface design supports IP Integrated
Services, a set of IP functions currently under discussion in the IETF
to provide multiple application-specific service types in an Internet
environment. The major components, which could have alternative
implementations tested on the vBNS, are a resource reservation
protocol, a flow discriminator, and a service scheduler. We can
evaluate the performance of these components in the vBNS in the
face of both time-critical and non-time-critical applications,
as well as test out integrated services mechanisms being developed
within the IETF, e.g.,
link
sharing, by Jacobson and Floyd at Lawrence
Berkeley Laboratories (LBL). In conjunction with class-based queuing
(an implementation of which UCL has developed), link sharing is a model
for allowing policy control over bandwidth utilization by a given
traffic (set of) source(s). NetStar has agreed in principle to
the interface specification, and the vBNS user community now has
the opportunity to review it as well.
This router development represents a major effort for MCI and the vBNS
user community and is dependent on feedback from the research community
and cooperation and resource committed by NetStar. MCI is pursuing
this project due to the level of interest from the Internet community
in IP Integrated Services, reflected at the NSF
Workshop for vBNS Researchers held in June 1995.
Network security
(lead: ddrew@mci.net)
Ken Rowe at NCSA and his group are developing some central audit
software for the I-WAY. Ken is also the coordinator for I-WAY Security
Incident Response team. NLANR hopes to leverage the I-POP/I-WAY
experience in scheduling vBNS resources in a secure manner. NLANR
participants have also written a Metacenter Security Add-on proposal,
which may include vBNS activity.
MCI is supporting ssh software on
some vBNS systems, and porting it to some vBNS architectures. Dale Drew (MCI) is the lead on this
effort.
Middleware: caching
(leads: kc@nlanr.net
and wessels@nlanr.net )
Claffy and Braun (SDSC) have proposed to develop and
deploy a scalable caching and replication system across strategic
network locations within the United States. Digital Equipment Corp. had
committed to significant cost sharing and collaboration, as an integral
part of this awarded proposal. The goal is to facilitate the evolution
of U.S. and international information provisioning with an efficient
national architecture for handling highly popular information.
Each NLANR site is participating with a caching server at their
site as part of this NLANR caching
project. NASA/Ames is also collaborating, supporting a cache
at FIX-West.
TCP analysis
(leads: mathis@psc.edu
and mahdavi@psc.edu )
Mathis and Mahdavi are investigating
analysis and simulation of current and proposed modifications to
aspects of algorithms in the Reno and Vegas TCP versions for fast
retransmit effects, RED/EPD, graceful interaction with suboptimally
compatible higher (http) and low (ATM) layer
protocols, and other issues under discussion on end2end-interest mailing
list. In addition the use of tools specifically for scientific
computing such as PVM/MPI, adds another layer of interaction to traffic
workloads that requires investigation of the dynamics and effect on
performance.
Network monitoring and statistics
(lead: kc@nlanr.net)
NLANR interest in statistics collection holds a
variety of motivations:
We hope to integrate valued functionality of the current NNStat and flow-based statistics into this
monitoring device, as well as use captured traffic traces or
theoretically developed traffic models to generate traffic for
simulations and testing. The monitoring device has an important role
for the vBNS of extending the NNStat-style monitoring to
include the HIPPI traffic at each SCC (the latter currently unavailable
since NNStat relies on the use of promiscuous mode by the Digital Alpha
workstation on the vBNS FDDI).
NCAR and NCSA worked with MCI to support vBNS-based demonstrations for
Comdex in Atlanta in April 1995 and Telecomm'95 in Geneva in August
1995.
NLANR sites have also been involved in supporting the I-WAY project, which yielded a significant
base of test applications to help define how to best use the vBNS once
the `friendly access period' ends. Support has
included: deployment of an IPOP platform; establishing additional routes;
and working with the various applications users who were
developing and testing distributed applications at the Supercomputing'95 show.
This application continues work demonstrated at both Supercomputing '93
and SIGgraph '94, showing both the usefulness of the CAVE for
scientific visualization and the feasibility of using high-speed
networks to distribute a complex scientific application across local
HIPPI or FDDI networks. For Supercomputing'95 they used the I-WAY ATM
network to distribute the calculation across the largest machines
available across the vBNS, yielding the largest simulation of
Einstein's equations ever attempted, and also to refine the scientific
visualization capabilities in the CAVE. The experiment provides an
important testbed for development of other large-scale distributed
scientific applications, as our numerical algorithms are common to many
scientific and engineering disciplines, therefore having direct
application to other fields of computational science.
Bob Wilhelmson (NCSA) and Crystal Shaw illustrated the visualization of
simulated tornados associated with supercell and non-supercell
convection.
Charles Goodrich (U. Maryland)
demonstrated real-time and near-real-time space weather forecasting
at SC'95 through coupled computer simulations using the combined
resources of PSC, CTC, and Goddard Space Flight Center (GSFC). A
real-time global MHD simulation of the magnetosphere on the T3D at PSC
provided results to continually update an ion kinetic simulation
running in tandem on the SP-2 at CTC.
Glen Wheless demonstrated the
Chesapeake Bay
Virtual Ecosystem (CBVE) to incorporate linked submodels of larval
behavior, primary and secondary production, benthic processes,
dissolved organic carbon, dissolved inorganic nitrogen and dissolved
oxygen, all of which will be spatially and temporally linked via their
existing 3D Bay circulation model.
This application demands high bandwidth. 12 bytes or roughly 100
bits must be transmitted per point; a T3D processor can update
roughly 1000 points per second using the algorithms involved. Thus
running on 128 processors would have required a bandwidth of 10
Mbits/sec. This was the configuration in which we had planned to
transmit to SC'95, but network difficulties at the show floor forced
us to use drastically reduced bandwidth of roughly 3 Mbits/sec.
This particular application will continue to be used in the normal
course of GC3 operations, to transmit data from the PSC T3D to a
display at NCSA. The software we developed for the demo are quite
general, and will allow us to transmit a variety of scientific
visualization geometries. With an appropriate machine on the
receiving end, these transmissions are very likely to be
bandwidth-limited. vBNS was used for one such transmission at
SC'95, when geometries from a molecular dynamics simulation were
sent from the PSC's C90 to the MetaCenter booth. I'm afraid I can't
offer bandwidth figures for this demo.
Additionally, Doug Roberts
and Dick Crutcher (NCSA,
UIUC) demonstrated a three-part radio
astronomy synthesis array observing the center of our Galaxy. This
application combines large-scale parallel computation, data mining and
transfer, and advanced 3-D visualization comparing the computed and
mined data.
Other demonstrations in computational biology include
The average bandwidth was 20 Mbit/second without optimizing the code for
vBNS (i.e. using the default window size). They were very pleased with
the performance of vBNS, it made the interactive computing on remote
machine possible for interactive virtual environment.
At Supercomputing'95, experiments in VR included those of:
In pursuit of increased effectiveness of wide area networks for real
scientific computing applications, Adam
Beguelin (PSC, CMU) is using communications
libraries that adapt to underlying network topology, and heterogeneous
workstation clustering, The latter application requires selective
routing of traffic because needed workstation clusters are separated
from the DMZ at some sites by one or more routers.
Joel Welling (PSC) has explored the
distribution of an algorithm for object-oriented
parallel volume rendering (VFleet) over geographically
distributed supercomputing resources. They have found thus far that
VFleet is less efficient in this mode than when run on a single machine
(e.g., PSC's T3D), so the results have not been of great practical use
yet.
Two visualization demonstrations at Supercomputing'95 were:
NCSA hired Mike Haberman for NLANR activities, effective September
1995.
Claffy began liaison efforts with the research community, including at
University of Colorado, LBL, USC/ISI, Digital, Xerox Parc, Bellcore,
Cisco, and Stanford University.
From what we can see, the NSF is definitely listening to and preparing
appropriate policy responses to this and all valuable feedback from the
research community, and is determined to address concerns that could
prevent the maximum return on the vBNS as an investment in the research
community. Furthermore, MCI is also undertaking collaborative efforts
with its equipment vendors to maximize the attractiveness (i.e.,
programmability, open architecture) of vBNS equipment to the network
research community. MCI has also consistently been very
collaborative with the NLANR group, so that vBNS and the NLANR
becoming quite integral to each other. We are quite optimistic about
the likelihood of both reasonable application of the AUP, and rapid
expansion of the vBNS to other experimental network testbeds, sites,
and offsite users. We look forward to a cooperative and productive (but
busy) coming year.
Working groups for supporting NLANR research agenda
The NLANR network research agenda is focusing on mechanisms that will
allow greater control over network integrity and performance. Key
areas in need of progress include: routing, accounting,
multiple qualities of service, multicast, collaborative environments,
and security. In each case we recognize a two-pronged problem:
changing the technology, from which the NSF is `three hops' away (NSF,
MCI, vendor/ietf, equipment/algorithm), and changing the community
mindset, from which the NSF is `two hops' away (NSF, policy on vBNS,
which is role model to rest of community).
EMMI multimedia interface (NCSA/AT&T)
Mike Haberman and John Lockwood (NCSA) and Jeff Winkler (SDSC) have tested AT&T EMMI video
equipment between NCSA and SDSC. The AT&T EMMI, an ATM-based
video/audio codec, provides a multimedia interface for a local host to
an ATM network. The video stream uses JPEG compression to yield five
levels of quantization to match the available bandwidth using ATM
Adaptation Layer 5, for bandwidth usage between 8 and 80 Mbps. The
audio stream uses AAL 1 with a bandwidth of 1.85 Mbps. The data
stream, which supports a White Board, runs over TCP/IP and on top of
AAL 5, but we have not evaluated this feature yet. We currently have
the EMMI's set up at NCSA and SDSC through the vBNS. The EMMI
interfaces are available to us on a temporary basis, to provide
feedback on their VTC usability.
Priority queueing
At Supercomputing'95 MCI used the NetStar routers in the vBNS to
demonstrate
priority queueing effects on the performance of multimedia
applications.
A video-capable workstation in Reston on the vBNS test network
captured video scenes using nv/vat software
and sent two traffic streams to a workstation on the
SC'95 showfloor. The two traffic streams generated from
the Reston workstation traversed the testnet where they
were subjected to traffic congestion. Queues with different priority
on the GigaRouter's ATM card supported the two traffic streams.
Under congestion, the stream in the lower priority rate queue experienced
longer queuing delay and eventually higher loss rates than the
stream in the high priority rate queue. Two windows on the display
workstation showed the same video scenes, one with good performance due
to higher priority queueing of its traffic, and the other with poor
performance due to the lesser service priority.
Advanced switches
MCI has begun to test OC-12-capable ATM switches, targeting switch
throughput capacity, response to congestion, SVC support, Virtual Path
switching, and manageability as major goals. MCI and NLANR
participants will collaborate in testing frame-oriented drop strategies
such as Early Packet Discard and Partial Packet Discard and alternative
queue disciplines for their utility in carrying IP traffic. We will
use simulation to extrapolate on laboratory and test network
measurements to show the improvement that can be obtained with specific
product modifications.
The community has still not converged on a standard set of measurements
that would allow comparisons; we are organizing an NSF workshop on
network analysis apects to be held in February at SDSC for vendors,
researchers, and ISPs to gather and share objectives and constraints.
ATM OC-3 monitoring development
As part of the vBNS project, MCI is planning the development of a
cell-level OC-3 monitoring device to trace the capture of IP headers
from ATM cells in order to study IP-over-ATM traffic dynamics with
microsecond granularity. MCI is developing the device on an
inexpensive standard computing platform for wide affordability and
programmability to support new data collection and analysis.
Treno
Mathis and Mahdavi (PSC) have developed a tool to test the performance
of network infrastructure under TCP-like loads. Because it is
based on TCP windowing algorithms, it has low impact on the network,
yet is able to provide accurate benchmarks. Mathis and Mahdavi hope
to add an ATM interface to the Treno server and attach it to the ATM
infrastructure of the vBNS, allowing the server to appear at the four
NAPs via the vBNS infrastructure. The server will be of use to the
Internet community as well as researchers of TCP performance.
External demonstrations
Mahdavi (PSC) assisted MCI in demonstrating the vBNS technology at the
AFCEA by working with the visualization staff at PSC to provide a live,
distributed demonstration of the use of supercomputers in volume
rendering applications.
NLANR research applications
Many of the applications on the vBNS thus far were intended for
demonstration at Physics
visualizing Einstein's gravitational waves
Ed Seidel (NCSA) in
collaboration with researchers at UIUC, is using the vBNS to
demonstrate a distributed,
heterogeneous, scientific solution of the full 3-dimensional Einstein
equations for gravitational fields, while simultaneously exploiting
the resources at various vBNS sites and displaying the results as they
are computed in the CAVE.
Earth system science
NCAR submitted four
friendly user vBNS applications that are operational:
and an additional application that is pending approval of
attachment of a non-vBNS site (the University of Colorado) to NCAR:
In addition, several atmospheric applications were demonstrated at
SC'95. Louis Rossi (Northwestern)
showed an
interactive simulation of contaminant evolution through porous
media, which computes the concentrations and pressure fields of the
contaminants remotely on at least one massively parallel supercomputer,
and displays the results in the CAVE as a user interactively adjusts
environmental parameters.
Astronomy
In their demonstration at Supercomputing'95, in connection with the
Grand
Challenge Cosmology Consortium's project, Michael Norman (NCSA) , Joel Welling (PSC) (NCSA, UIUC,
and the Beckman Institute) and colleagues simulated the merger
of the Milky Way and Andromeda galaxies using multiple massively
parallel supercomputers located at all four NSF centers. The project
illustrated the concept of collaborative distributed computing, wherein
two simulation codes of different type are coupled into a single
multiphysics model. From their conference report:
A simulation of the collision of two galaxies was run on the PSC's
Cray T3D, and coordinates for star clusters were transmitted in real
time across the vBNS for display. For SC'95 these coordinates were
displayed on a Silicon Graphics Onyx at the conference in San Diego,
in a virtual reality environment, as part of the GII Testbed
project. Technical problems prevented successfully displaying the
results on the NII Wall at the show, but we were able to run the
program to an Immersadesk in the MetaCenter booth on the exhibition
floor. The GC3 group won an High Performance Computing Challenge
award for the software system of which this demo was a part.
Biology
Supercomputing'95 also provided Wolfgang F. Kraske an
opportunity to demonstrate a distributed
biomedical visualization system using the 140 Gflops processing
throughput from a HIPPI connected Cray T3D, Intel Paragon and Intel
Delta linked via a 622 Mbps asynchronous transfer mode (ATM) OC12 line
to a remote (12 miles away) ATM switched workstation cluster. They
connect to the IBM SP2 at Cornell and one at Argonne National
Laboratory via OC3 linkage, and connect to the Maui IBM SP2 via the
ACTS satellite. At the workstation cluster, the OC12 line is ATM
multicast switched into a two level tree configuration servicing 19
workstations linked by OC3 lines. The terminals of the workstation
cluster are located at 7 hospitals across the Los Angeles metropolitan
area. Residual bandwidths on the workstation cluster are used to
support video tele-conferencing and distributed patient data queries
between the 7 facilities with distributed local computation providing
image processing and display. The 90 GFLOP load on the supercomputers
satisfies the requirements of asynchronous tasks such as virtual
reality, interactive volumetric visualization and NGC tissue
classification algorithm processing. The data sets comprise two
GigaByte of Biomedical scan data acquired with x-ray computed
tomography (CT), magnetic resonance imaging (MRI) and positron emission
tomography (PET) scanners located at the 7 USC hospitals.
(Several applications were intended to run at SC'95 but could not do so
due to I-WAY operational difficulties. However these users did have
the opportunity to use their applications on the vBNS following the
conference.)
* Onyx -- SGI Onyx, the machine that drives the CAVE. no network vBNS Internet
Hardware Onyx* Onxy and PC** Onyx and PC**
Start up time 4 minutes 6 seconds 20 seconds
Interactive response 2 minutes 4 seconds 1 second or less
** PC -- SGI power challenge with 16 process, resides in Champaign Ill.
Virtual reality (CAVE)
Argonne and NCSA are investigating performance models of
interactive, immersive visualization for scientific applications,
looking at methods of removing the barrier of distance while sharing a
virtual experience. Argonne and NCSA have proposed to NSF that the
vBNS be extended via the Ameritech NAP to Argonne National
Laboratories, where connecting to the CAVE there would enhance the
progress of this research effort.
Visualization
Several visualization projects are using vBNS resources, some of which
were demonstrated at SC'95.
Performance measurement
Application level usage statistics
Von Welch (NCSA) provided the
vBNS with a
library for logging application level network usage information.
SNMP visualization
Daniel A. Reed (UIUC) and
colleagues are demonstrating applications for visualization of
network performance and usage statistics.
ATM traffic measurement
David Tipper
and Sujata Banerjee
are testing an
ATM broadband traffic generator/measurement device
donated by Hewlett-Packard, to characterize and
experiment with generation of ATM traffic workloads.
Miscellaneous
New personnel
NCAR hired Chris Fair to perform the functions of the NLANR engineer
funded by the NLANR, effective 1 November 1995.
Feedback from the user community
outreach
Charlie Catlett has been serving as Technical Advisor to NSF (Steve
Goldstein, NCRI), representing the U.S. in G7 high speed global network
testbed planning, one of eleven projects outlined at the G7 Summit in
Brussels in early 1995. He participated in two meetings this quarter
with G7 representatives and telecommunications carriers from each
country.
Acceptable use policy
Several potential and active vBNS users have expressed concern
regarding the nature of the vBNS as an experimental testbed. A
realistic wide-area test of many research applications, such as those
for real-time data distribution systems, require considerable
investment by participating sites to get connected, an unlikely
prospect if the vBNS were not available on a routine basis. One
researcher noted:
How many of the really useful experiments would have been done on the
original NSFnet if the ground rules had been similar to those of the
vBNS. Quite likely that the NSFnet would not have progressed very far
beyond high speed connections among supercomputer centers.
The vBNS is chartered for research in a variety of networking and
application areas, much of which is most suited to infrastructure that
is well coupled to the commercial production Internet. This close
coupling, however, presents potential policy problems with use of the
vBNS, described further in the next section.
NSF sponsored vBNS workshop
NSF hosted a workshop entitled, vBNS and Networking and Application
Researchers in Washington, DC on 22-23 June 1995. The purpose of
the meeting was to begin a dialogue among networking researchers,
applications researchers, NSF staff and MCI staff concerning emerging
opportunities associated with the vBNS. The workshop was chaired by
Dr. Jonathan Turner (Washington University, St. Louis), and Dr. Paul
Messina (Caltech). NLANR representatives (Randal Butler (NCSA),
K. Claffy and Hans-Werner Braun (SDSC), Charlie Catlett (NCSA),
Richard Loft (NCAR), and Jamshid Mahdavi (PSC)) represented their sites
at the workshop. The sites were expecting an NSF report of the
workshop shortly after, in order to respond to feedback from the
research community articulated therein, but this report has not yet
finalized. However, several concerns clearly emerged during the
workshop itself, including the need for
contributors to
this report included:
Randy Butler,
Charlie Catlett,
Bilal Chinoy,
Bruce B. Johnson,
Jamshid Mahdavi,
Matthew Mathis, and
Marla Meehl
[NLANR home page]
info@nlanr.net
27 dec 1995