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Lessons Learned for OSI at INTEROP 91
By Susan Hares -- MERIT/NSFNET
Thirty networking technology vendors worked together to provide a
demonstration of OSI applications and network protocols over the
internet's Infrastructure for INTEROP 91. The National Agency
networks participating in this event were NSFNET, ESNET, and
NASA. This demonstration linked workstations on the convention
show floor with workstations in Europe, the United States and
Australia (see figure 1).
This INTEROP 91 demonstration showed how co-operation from many
network service providers and vendors can make OSI applications
over the internet a reality. The lessons learned from this
demonstration pave the way for continuing OSI traffic in the
internet. One of the most valuable lessons from INTEROP 91 was
that we can make OSI work in the internet. OSI vendors who
participated in the OSI demonstration want to continue to use
the internet during the next year.
The most painful lessons at INTEROP 91 were the obstacles to
showing the OSI applications. The OSI Demonstration booth
encountered three types of problems:
- problems setting up the physical network,
- problems setting up and debugging a multi-protocol
network,
and
- problems configuring OSI routers and debugging OSI
related problems.
Setting up a huge multi-protocol network in days is close to
impossible. Only extensive planning and testing, and excellent
co-operation from internet community (vendors and network service
providers) has allowed INTEROP to accomplish this difficult task
year after year. Every booth encountered some problems due to
the physical network set-up and multi-protocol network debugging.
These types of problems are normal when setting up something like
the INTEROP show floor. In addition, the OSI Demonstration booth
encountered problems due to:
- problems with the set-up of OSI routing of
Connectionless Network Layer Protocol (CLNP) packets
via static configurations, and
- lack of OSI network debugging tools on every machine.
Sometimes OSI application traffic flowed from the show floor to
Europe, but not between booths at the show floor.
figure 1 - OSI Infrastructure in the Internet
(picture available for anonymous ftp in the file lesson.01.ps
on merit.edu in the directory /pub/iso/noop/tutorial)
1
What Happened at INTEROP 91
----------------------------
OSI demonstrations on the INTEROP 91 show floor included OSI
Vendor booths and the collaborative OSI Demonstration booth (see
figure 3). ISO's End System to Intermediate System (ES-IS)
protocol was used between multiple hosts (end system) and routers
(intermediate system) from many different vendors. ISO's
Intermediate System to Intermediate System (IS-IS) protocol was
demonstrated in the OSI Demonstration booth. IS-IS is an ISO
intra-domain routing protocol which is similar to Internet
Gateway Protocols (IGPs) in the IP suite. NSFNET has used an
implementation of the IS-IS routing protocol adapted for IP since
1988.
The OSI applications demonstrated at the OSI demonstration booth
and Vendor booths included four major OSI applications: X.400,
File Transfer Access and Management (FTAM), Virtual Terminal
(VT), and X.500. X.500 was demonstrated over both IP and CLNP
showing that OSI applications do not have to be limited to OSI
lower layer stacks. Figure 2 shows Internet applications which
have some of the functions of these four major OSI applications.
OSI application Internet Application(s)
with some of the same
functions
=================== ======================
VT telnet
FTAM ftp
X.400 SMTP
X.500 none *1
Note:
*1 - The TCP/IP protocol suite has no protocol that provides the
distributed directory service that X.500 provides. X.500 is
being used over TCP/IP in the internet.
Figure 2 - OSI applications compared to TCP/IP applications
A prototype of the ISO Inter-Domain Routing Protocol (IDRP) was
demonstrated. IDRP provides a means of passing OSI routing
information between domains and applying policy filters to that
routing information. An IP protocol which provides the some this
functionality for IP is the Border Gateway Protocol (BGP). The
IDRP protocol is in the second stage of the development process
as an ISO standard. The development of the IDRP prototype
provided a great deal of feedback on this ISO standard (CD 10747)
to the US committee working on this standard. T h e I D R P
prototype passed traffic between the nodes in the OSI
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demonstration booth, the IBM booth, and nodes on the ANS/NSFNET
T3 test network. The IDRP protocol was developed by Dave Katz of
Merit, and further details can be obtained from Merit.
figure 3 - OSI at INTEROP 91
(figure available for anonymous ftp on merit.edu on the
directory /pub/iso/noop/tutorial/lesson.03.ps
Lesson 1 - People make OSI Work
Many talented people made the OSI Infrastructure demonstration
happen. I am convinced that the internet networks work and
advance because talented individuals push and push until the
network technology advances. Companies support technology
advances by putting the punch behind their people.
Cyndi Jung (3COM) helped me organize the OSI demonstration booth
and internet testing. She spent countless hours working on the
OSI Hot Stage and the Backbone Hot stage. The router vendors
(cisco Systems, Proteon, 3COM, Wellfleet, Network Systems, DEC)
spent extra time helping out the internet, Hot Stages and IS-IS
testing. Two especially hard workers were Paulina Knibbe
(cisco) and Ed Stern (Proteon).
End system vendors worked with Network service people to set-up
the OSI application demonstrations. Night after night Charlie
Alberts (Banyan), John Davis (Banyan), Kevin Jordan and others
from CDC, Eva Kuiper (HP), and other vendors tested FTAM, X.400
and X.500 across the internet. Cathy Wittbrodt, Arlene
Getchell, Tony Genovese of ESNET made the ESNET networks and OSI
applications work. Juha Heinanen and lots of people from the
RARE-WG4 CLNS project helped connect Europe to this
demonstration. Linda Winkler (Argonne Labs), Alan
Clegg(CONCERT), Mark Knopper (MERIT), Walt Lazear (MITRE) and
John McGuthry (MITRE), Doug Montgomery (NIST), Cathy Fouston
(Sesquinet) and Bill Manning (Sesquinet) got more OSI
Applications working across the internet. The roll call for the
network path includes many of the people who make IP a reality
today: Vince Fuller and Ron Roberts (BARRNet), Mark Oros
(ICMNet), Tim Salo and Jeff Wabik (Minnesota Super Computer),
John Curran (NEARnet), Dave O'Leary (SURANet) and Andrew Partan
(UUNET).
Some of the networks companies that lent their people, equipment
and push to the OSI infrastructure demonstration included:
Alcafel TITN, 3COM, ANS, Argonne National Laboratory, AT&T,
Banyan, BARRNet, CERFNET, CERN, CICNET, cisco, Control Data
Corporation, CONCERT, Digital Equipment Corporation, ESNET,
Frontier, HP, IBM, ICMNet, INFN (Italy), networks in Spain,
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networks in Germany, MERIT, MIDNET, MITRE, Minnesota
Supercomputer Network, MRnet, NASA Science Network, NorduNet,
NEARnet, Network Systems, Novell, NIST, OSINET, Pyramid, RETIX,
SURANet, SWITCH (Switzerland), Tandem, UNISYS, UNISYS-Australia,
Wallongong Group, and Westnet.
One thing that helped harness these people were numerous
conference calls provided by MCI.
Lesson 2 - Build on the Past
The OSI Infrastructure demonstration is the culmination of years
of work. The idea for the Infrastructure demonstration was
conceived in mid June of 1991 as a milestone for the long term
work in the US internet. The extension of OSI application
traffic to some 30 networking technology vendors over a good
portion of the internet took place within 3 months. The rapid
deployment of this Infrastructure was due to:
- past work in OSI by Pilot Projects in Europe
and the US, and
- outstanding work by each of the networks and
companies participating in the demonstration.
The OSI support in routers and End systems has matured a lot in
past year. The Pilot projects in European and the US have caused
some of these products to mature. These Pilot projects have
tested products, reported bugs, and suggested improvements to
user interfaces and product capabilities.
Pilot Project History
---------------------
The NSFNET demonstrated a prototype implementation of the
Connectionless Network Protocol (CLNP) at INTEROP 89 in September
of 1989. The T1 NSFNET has been capable of routing
Connectionless Network Protocol (CLNP) since August of 1990.
During August of 1990, MERIT exchanged CLNP packets with sites in
Europe as part of a Pilot project involving European Pilot
Project sites and the NSFNET. During INTEROP 90, CLNP packets
were exchanged between systems on the show floor systems in
Europe which were a part of the European RARE-WG-4 CLNS Pilot
Project.
During the time period between October 1990 and April 1991, MITRE
and other US companies exchanged information using OSI
applications (FTAM and X.500) with systems in Europe
participating in this European RARE-WG-4 CLNS Pilot project. In
April of 1991, two US sites - Merit and MITRE - successfully sent
files between US systems on the internet over a pure OSI stack
using the CLNP for the network layer protocol. The network
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pathway between these hosts was set up with the help of MichNet,
UUNET, and NSFNET. These OSI hosts at MITRE and MERIT transferred
several files.
Energy Science Network (ESNET) has been working toward providing
OSI within its backbone since early 1991. During the June of
1991, ESNET was capable of routing CLNP packets to several of the
sites within ESNET. By September, ESNET could route CLNP
packets in all routers on ESNET's backbone. By October 1991,
several ESNet Sites had hosts which exchanged information using
OSI applications (FTAM, X.400, X.500) over the pure OSI stack
using this CLNP pathway.
Lesson 3 - Test Everything You Can
The Testing for the OSI demonstration booth was continuous from
mid-June (when the idea was conceived) until INTEROP 91. While
two Hot Stages were involved in this testing, most of the network
testing for the OSI Infrastructure demonstration took place
outside of the Hot Stage time periods. The following testing
was done:
a.) pre-Hot Stage internet Set-up and Tests
b.) NIST IS-IS test Lab
c.) OSI Hot Stage
d.) backbone Hot Stage
e.) internet Testing of Applications
All of this testing took time, but pointed out the need for an
on-going test bed. The IETF (Internet Engineering Task Force)
Network layer OSI OPerational (NOOP) working group will be
investigating how to organize a test bed for OSI. This test bed
needs to have all routers running CLNP, and IS-IS within some
routers. This national test bed needs to have end systems
actively running OSI applications. Pieces of this test bed need
to be linked together using the production internet. OSI
applications need to run between systems on the test bed as well
as systems off the production internet.
Problems on operational networks can be reduced by putting new
router software into test bed nodes, and passing OSI and IP
application traffic over these routers. A continual testing
of router and application software will lessen the time needed
for INTEROP testing. An added benefit of a national test bed is
that additional demonstrations of OSI applications over the
internet could be staged quickly.
Pre-Hot Stage Internet Set-up and Tests
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---------------------------------------
Setting up each internet connection to a site running an OSI
application took the following steps:
step 1 - Get the permission of one or more of network
service providers to pass CLNP packets.
step 2 - Set up routers in the networks to route CLNP
packets.
step 3 - Set-up OSI applications on hosts.
step 4 - Test OSI applications over these networks.
During June, July and August a great number of the sites on the
internet followed these four steps and got OSI application
traffic flowing across the internet.
NIST testing of IS-IS
-----------------------
The National Institute of Standards and Technology (NIST) hosted
a week of pre-INTEROP 91 dynamic router interoperability testing
August 12-16. The open lab was part of NIST's Cooperative
Laboratory for OSI Routing Technology program. Testing addressed
the Draft International Standard specification of the IS-IS
protocol (DIS 10589) and the operation of the IS-IS protocol in a
live multi-vendor Intermediate and End System environment. OSI
routing was tested over Ethernet. Vendors participating in the
IS-IS testing included 3COM, Digital Equipment Corporation,
Proteon and Wellfleet. This testing allowed the OSI Hot Staging
to use the IS-IS protocol to support OSI applications. Breaking
off routing protocol testing from OSI application testing greatly
improved the OSI Hot Staging efforts.
OSI Demonstration Booth Hot Staging
-----------------------------------
During the last week of August 1991, a "hot stage" was held for
the OSI demonstration booth. A T1 link from BARRNET to the OSI
Hot Stage was essential for the success of the testing between
vendors and OSI infrastructure demonstration. Full fledged
internet access allowed the vendors to exchange mail and obtain
software changes from their company. Due to the full fledged
internet access not all team members working on an OSI product
needed to attend the hot stage. Several experts from OSI vendors
used the internet to login to "hot stage" systems. Without
leaving his/her desk at work, an expert could examine problems
and try out solutions. Companies provided expertise without the
cost of sending an additional person to the "hot stage".
Application traffic for the OSI Infrastructure demonstration
flowed across the T1 link to BARRNET. Due to this T1 link,
Infrastructure demonstration through out the internet could be
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debugged from the "hot stage" area.
Backbone Hot Stage
--------------------
INTEROP 91 Backbone Hot staging started during the last week of
August and continued through-out September. The backbone hot
stage had the challenging task of putting IP, OSPF, CLNP on
interfaces with FDDI, serial lines, ethernet, ISDN. Most
networks only use a fraction of these protocols. The combination
of these protocols in a multi-vendor environment broke new
ground. The backbone "Hot Staging" showed that not only OSI, but
other protocols can benefit from a national test-bed for router
software.
Another lesson from the Backbone Hot Staging is the need for good
internet connectivity to any "Hot Stage" activity. During the
early stages of the Backbone Hot Staging, the internet connection
was not a full T1 link. Without this T1 link to the Hot
Staging, access to Internet resources for exchange of mail or
code updates was slow and problems took longer to fix. Experts
from router vendors could not quickly access the routers backbone
staging from their desk as they could with the OSI "hot stage".
Lesson 4 - OSI addressing needs full X.500 service
Keeping up with the changing OSI addresses for each router and
end system was quite a chore. The X.500 work for placing network
addresses or host addresses in a global X.500 directory is not
complete. While there is progress being made on these issues in
several pilot projects, most of the addresses for the routers and
end systems for INTEROP 91 were kept in files. Managing these
files took a great deal of my time, and needs to be improved for
future internet work.
An interim place to register network addresses and OSI
application addresses needs to be in place while X.500 work
continues. As a result of the INTEROP 91 work, the mail group
osi-pilot@merit.edu will help work with this address nightmare.
Router and end system vendors use different formats to express
network address (Network Service Access Point (NSAP) addresses)
and OSI application addresses. A common format for expressing
these addresses would greatly speed debugging of network
problems. Network debugging tools would only have to function on
one format, not several.
Lesson 5 - Routing Protocol (IS-IS) is much better than Static
configurations
The OSI Demonstration booth ran IS-IS between routers within the
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booth, BARRNEt, and 3COM. The IS-IS routing protocol handled
loss of links, and automatically switched to a backup route. The
routers involved in the IS-IS protocol (3COM, Proteon, and
Wellfleet) passed lots of traffic to the internet.
The INTEROP 91 show floor backbone routers ran static route
configurations for CLNP. While the software on the routers
running these static configurations ran well, setting up these
configurations for the large show network was difficult. The
lessons the internet at large has learned about static routes for
IP were re-learned as we tried to use static routes for OSI. The
worst stress on static routes came when the INTEROP show floor
team changed router vendors for some the show floor routers (due
to non-OSI protocol issues) on the day before the show opened.
This last minute change required a re-doing a lot of OSI static
routing configurations in the new vendors routers on within hours
of the when the INTEROP 91 show.
Even with improved tracking of router configurations by the show
floor NOC, the sheer amount of static configurations made life
difficult for the show floor network. In fact, some problems in
booth to booth connections were caused by human errors in static
configurations.
In contrast, the show floor configurations for the internet were
only a few entries. Since OSI routing allows many network
addresses to be summarized by a shorter address string (or
network prefix), the static configurations for the internet were
few (2-4) and of short length (1-2 octets).
The use of IS-IS within the show network would greatly reduce the
amount of effort needed to support OSI traffic within the show
network. Since INTEROP 91, NASA Science network has employed
OSPF for IP and IS-IS for OSI. NASA Science network added IS-IS
to it's network running OSPF and encountered few problems. Using
IS-IS for INTEROP 92 seems within today's technical reach.
Lesson 6 - The Challenge of the INTEROP Show Floor has Grown
Success in networking is the best of all times and the worst of
all times. The INTEROP show floor has grown from a few machines
hooked together by 2 or 3 routers on an ethernet to a network
spanning all possible technology with over 25 backbone routers.
What networks grow over months, INTEROP 91 tried to do in 3 days.
The OSI demonstration encountered the problems you would expect
in such an environment. The physical and logical connections
within the booth and to the outside needed to be made prior to
any network testing. Little things like power coming in a few
hours behind the schedule become critical in this compressed time
schedule. Demonstrations which expect to work in all three
areas: within a booth, between booths, and between the booth and
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sites on the Network need every second of testing time. Also, in
an Infrastructure or internet wide demonstration a large number
of people are needed to solve a problem. A great deal of
scheduling needs to take place to allow quick debugging. The
network connection needs to be ready at least a full day in
advance of the show floor opening to give an Infrastructure
demonstration time to check out the demonstration.
The INTEROP 91 OSI demonstration uncovered a need for improvement
in the show floor scheduling and debugging. Infrastructure
debugging sessions were scheduled and dismissed due to the lack
of network connectivity. The final OSI link to the internet came
up within an hour of show time. Fortunately, due to lots of pre-
testing, most things worked. But an hour is just not enough time
to fix any problems.
Several excellent volunteers helped set-up INTEROP 91. People
who know how to set-up IP networks worked long and hard on the
show floor network. Was it the static configurations for OSI
that slowed the network set-up down? Was it sheer amount of
physical set-up? Was it lack of wide spread knowledge of OSI?
Was it the last minute switch of router vendors for some of the
show floor routers? Was it something else? Improvement is
needed for INTEROP 92.
One improvement OSI vendors need to make is a common set of
network tools. Network tools include an OSI ping, an OSI
traceroute, and a listing of OSI network routing tables. While
we expect these functions to work across all IP hosts and
routers, this functionality is not available on every OSI host.
Most OSI routers provide these network tools. However, not all
OSI pings and traceroute interoperate between routers. As a
result of INTEROP 91 the IETF Network layer OSI OPerational
(NOOP) group is preparing an RFC on OSI network tools.
Lesson 7 - IP versus OSI - Are we learning or emoting?
The friendly competition between IP and OSI has strengthened both
protocol suites. The strength of IP and the internet has been
the "make it work" attitude. The ISO protocols are agreements
between many nations. Both groups have something they can learn
from the other protocol suites' successes and failures.
When this friendly competition and bantering gives way to
unthinking emotional arguments, we all cease learning. While
working on INTEROP 91, I saw people with IP backgrounds learn how
to make OSI work in their networks. To my delight, people from
OSI backgrounds or companies learned a lot about the internet and
IP. Sadly, I also witnessed some of the most close minded
emotional arguments about OSI and IP. I salute those IP people
who took time to strengthen IP by learning about OSI. I salute
those OSI people who made OSI stronger by learning about IP and
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the internet. I suppose as always, this INTEROP was the best of
all times and the worst of all times.
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