| Rfc | 1070 |
|---|
| Title | Use of the Internet as a subnetwork for experimentation with the OSI
network layer |
|---|
| Author | R.A. Hagens, N.E. Hall, M.T. Rose |
|---|
| Date | February 1989 |
|---|
| Format: | TXT, HTML |
|---|
| Status: | UNKNOWN |
|---|
|
Network Working Group R. Hagens
Request for Comments: 1070 U of Wiscsonsin - Madison
N. Hall
U of Wiscsonsin - Madison
M. Rose
The Wollongong Group
February 1989
Use of the Internet as a Subnetwork for
Experimentation with the OSI Network Layer
Status of this Memo
This RFC proposes a scenario for experimentation with the
International Organization for Standardization (ISO) Open Systems
Interconnection (OSI) network layer protocols over the Internet and
requests discussion and suggestions for improvements to this
scenario. This RFC also proposes the creation of an experimental OSI
internet. To participate in the experimental OSI internet, a system
must abide by the agreements set forth in this RFC. Distribution of
this memo is unlimited.
WARNING
The methods proposed in this RFC are suitable ONLY for experimental
use on a limited scale. These methods are not suitable for use in an
operational environment.
Introduction
Since the International Organization for Standardization (ISO) Open
Systems Interconnection (OSI) network layer protocols are in their
infancy, both interest in their development and concern for their
potential impact on internetworking are widespread. This interest
has grown substantially with the introduction of the US Government
OSI Profile (GOSIP), which mandates, for the US Government, the use
of OSI products in the near future. The OSI network layer protocols
have not yet received significant experimentation and testing. The
status of the protocols in the OSI network layer varies from ISO
International Standard to "contribution" (not yet a Draft Proposal).
We believe that thorough testing of the protocols and implementations
of the protocols should take place concurrently with the progression
of the protocols to ISO standards. For this reason, the creation of
an environment for experimentation with these protocols is timely.
Thorough testing of network and transport layer protocols for
internetworking requires a large, varied, and complex environment.
While an implementor of the OSI protocols may of course test an
implementation locally, few implementors have the resources to create
a sufficiently large dynamic topology in which to test the protocols
and implementations well.
One way to create such an environment is to implement the OSI network
layer protocols in the existing routers in an existing internetwork.
This solution is likely to be disruptive due to the immature state of
the OSI network layer protocols and implementations, coupled with the
fact that a large set of routers would have to implement the OSI
network layer in order to do realistic testing.
This memo suggests a scenario that will make it easy for implementors
to test with other implementors, exploiting the existing connectivity
of the Internet without disturbing existing gateways.
The method suggested is to treat the Internet as a subnetwork,
hereinafter called the "IP subnet." We do this by encapsulating OSI
connectionless network layer protocol (ISO 8473) packets in IP
datagrams, where IP refers to the Internet network layer protocol,
RFC 791. This encapsulation occurs only with packets travelling over
the IP subnet to sites not reachable over a local area network. The
intent is for implementations to use OSI network layer protocols
directly over links locally, and to use the IP subnet as a link only
when necessary to reach a site that is separated from the source by
an IP gateway. While it is true that almost any system at a
participating site may be reachable with IP, it is expected that
experimenters will configure their systems so that a subset of their
systems will consider themselves to be directly connected to the IP
subnet for the purpose of testing the OSI network layer protocols or
their implementations. The proposed scheme permits systems to change
their topological relationship to the IP subnet at any time, also to
change their behavior as an end system (ES), intermediate system
(IS), or both at any time. This flexibility is necessary to test the
dynamic adaptive properties of the routing exchange protocols.
A variant of this scheme is proposed for implementors who do not have
direct access to the IP layer in their systems. This variation uses
the User Datagram Protocol over IP (UDP/IP) as the subnetwork.
In this memo we will call the experiment based on the IP subnet EON,
an acronym for "Experimental OSI-based Network". We will call the
experiment based on the UDP/IP subnet EON-UDP.
It is assumed that the reader is familiar with the OSI connectionless
network layer and, in particular, with the following documents:
RFC 768
User Datagram Protocol.
RFC 791
Internet Protocol.
ISO 8473
Protocol for Providing the Connectionless mode Network Service.
ISO DP 9542
End System to Intermediate System Routing Exchange Protocol for
Use in Conjunction with the Protocol for the Provision of the
Connectionless-mode Network Service (ISO 8473).
ISO TC 97/SC 6/N xxxx
Intermediate System to Intermediate System Intra-Domain Routing
Exchange Protocol.
PD TR 97/SC 6/N 9575
OSI Routing Framework.
Definitions
EON
An acronym for Experimental OSI Network, a name for the proposed
experimental OSI-based internetwork that uses the IP over the
Internet as a subnetwork.
EON-UDP
A name for the proposed experimental OSI-based internetwork that
uses the UDP/IP over the Internet as a subnetwork.
ES
End system as defined by OSI: an OSI network layer entity that
provides the OSI network layer service to a transport layer.
IANA
The Internet Assigned Numbers Authority. Contact Joyce K.
Reynolds (JKREY@ISI.EDU).
IS
An OSI network layer entity that provides the routing and
forwarding functions of the OSI connectionless network layer.
OSI CLNL
OSI connectionless network layer.
NSDU
Network Service Data Unit.
PDU
Protocol Data Unit, or packet.
NPDU
Network Protocol Data Unit.
ISO-gram
An NPDU for any protocol in the OSI CLNL, including ISO 8473
(CLNP), ISO DP 9542 (ES-IS), and ISO TC 97/SC 6/N xxxx (IS-IS).
Participating system
An ES or IS that is running a subset of the OSI CLNL protocols and
is reachable through the application of these protocols and the
agreements set forth in this memo.
Core system
An ES or IS that considers itself directly connected to the IP
subnet for the purpose of participating in EON.
NSAP-address
Network Service Access Point address, or an address at which the
OSI network services are available to a transport entity.
SNPA-address
SubNetwork Point of Attachment address, or an address at which the
subnetwork service is available to the network entity.
Issues to be Addressed by this Memo
In order to make the experimental OSI internet work, participating
experimenters must agree upon:
- how ISO-grams will be encapsulated in IP or UDP packets,
- the format of NSAP-addresses to be used,
- how NSAP-addresses will be mapped to SNPA-addresses on
the IP subnet,
- how multicasting, which is assumed by some OSI CLNL
protocols, will be satisfied, and
- how topology information and host names will be
disseminated.
This memo contains proposals for each of these issues.
Design Considerations
The goals of this memo are:
- to facilitate the testing of the OSI network layer
protocols among different implementions,
- to do this as soon as possible, exploiting existing
connectivity,
- to do this without requiring any changes to existing IP
gateways,
- to create a logical topology that can be changed
easily, for the purpose of testing the dynamic adaptive
properties of the protocols, and
- to minimize the administrative requirements of this
experimental internetwork.
The following are not goals of this memo:
- to permit the use of arbitrary ISO-style
NSAP-addresses,
- to require that participants have working
implementations of all of the OSI routing protocols
before they can participate in any capacity,
- to permit or encourage the use of existing IP routing
methods and algorithms for the routing of ISO-grams
among participating ESs and ISs,
- to create a production-like environment accommodating a
very large number of systems (ESs, ISs or both), and
- to provide or to encourage IP-to-CLNP gatewaying.
Encapsulating ISO-grams in IP datagrams
The entire OSI network layer PDU, whether it be an ISO 8473 PDU, an
ISO DP 9542 PDU, or an IS-IS PDU, will be placed in the data portion
of an IP datagrams at the source. The ISO 8473 entity may fragment
an NSDU into several NPDUs, in which case each NPDU will be
encapsulated in an IP datagram. The intent is for the OSI CLNL to
fragment rather than to have IP fragment, for the purpose of testing
the OSI CLNL. Of course, there is no guarantee that fragmentation
will not occur within the IP subnet, so reassembly must be supported
at the IP level in the destination participating system.
SNPA-addresses (Internet addresses) will be algorithmically derived
from the NSAP-addresses as described below. The "protocol" field of
the IP datagram will take the value 80 (decimal), which has been
assigned for this purpose.
NSAP-Address Format
The OSI internetwork described here will form one routing domain,
with one form of NSAP address recognized by all level 1 routers in
this domain. Other address formats may be agreed upon in later
editions of this memo.
The address format to be used in this experiment is that specified in
RFC 1069. According to RFC 1069, the low-order portion of the Domain
Specific Part of the NSAP address may vary depending on the
conventions of the particular routing domain. For the purposes of
this experiment, we shall use the following address format:
Address Format for EON
Octet Value Meaning
-------- ------------- ----------------------------------------
1 47 Authority and Format Identifier
2,3 00, 06 International Code Designator
4 3 Version Number
5,6 0 Global Area Number, see RFC 1069
7,8 RDN Routing Domain Number, assigned by IANA
9-11 0 Pad
12,13 0 LOC-AREA, see below
14,15 0 unused
16-19 A.B.C.D Internet address
20 NSAP Selector, assigned IANA
Note: It is our desire that the address format used by EON be
consistent with RFC 1069. To that end, the address format
proposed by this RFC may change as future editions of RFC 1069
become available.
The mapping between NSAP-addresses and SNPA-addresses (Internet
addreses) on the proposed IP subnet is straightforward. The SNPA-
address is embeded in the NSAP-address.
There are several ways in which the LOC-AREA field could be used.
(1) Assign local areas, administered by the Internet Assigned Numbers
Authority (IANA). The advantage of this is that it permits
experimentation with area routing. The disadvantage is that it
will require an additional directory service to map host names to
NSAP-addresses. We would like to use the existing domain name
servers to derive Internet addresses from names, and we would
like NSAP-addresses to be derivable from the Internet addresses
alone.
(2) Have one local area in the EON, with LOC-AREA value 0. This
would eliminate the problem of name-toNSAP-address binding, but
would not permit experimentation with area routing. It would
not, however preclude the use of areas later, for example, when
OSI directory services are widely available.
(3) Make the local area a simple function of the Internet address.
The advantage of this is that it would permit experimentation
with area addressing without requiring additional directory
services, but the areas derived would not be under the control of
the experimenters and may not correspond to anything useful or
meaningful for the purposes of this experiment.
We believe that initially, the preferred alternative is to use only
zero-valued local areas. Later editions of this memo may contain
proposals for use of the local area field, when the IS-IS proposal is
more mature and perhaps when OSI directory services are in use among
experimenters.
The value of the high-order portion of the DSP will be set in
accordance with RFC 1069.
Other NSAP-Address Formats
PDUs carrying NSAP-addresses of other formats can be routed through
this domain. This is the job of the level 2 routers, described in
the IS-IS document.
Multicast Addresses on the IP Subnet
The ES-IS and IS-IS routing exchange protocols assume that broadcast
subnetworks support two multicast addresses: one for all ESs and the
other for all ISs. While one could obviate this issue by treating
the IP subnet as a general topology subnetwork or as a set of point-
to-point links, it is also desirable to treat the IP subnet as a
broadcast subnetwork for the purpose of testing those parts of an
implementation that run over broadcast subnets. A participating
implementor not having access to several local machines running the
OSI CLNL may test the protocols over the IP subnet as if the IP
subnet were a broadcast subnet.
The multicasting assumed by the OSI CLNL can be simulated by a small
sublayer lying between the OSI CLNL and the IP subnet layer. For the
purpose of this discussion, call this sublayer an SNAcP, a SubNetwork
Access Protocol, in OSI argot. In each system the SNAcP caches a
table of the Internet addresses of systems that it considers to be
reachable in one ISO 8473-hop over the IP subnet. These are called
"core" systems. In this sense, the use of the cache simulates a set
of links over which a system will send ISO configuration messages (ES
Hello, IS Hello, etc.) when it comes up. As a local matter, the
table of core systems may or may not expand during the system's
lifetime, in response to configuration messages from other core
systems.
On the outgoing path, the SNAcP accepts an ISO-gram and a parameter
indicating the intended use of this ISO-gram: send to a single
system, to all ESs, to all ISs, or to all systems. If the indended
destination is a single system, the ISO-gram is sent only to its
destination. Otherwise, the SNAcP makes a copy of the ISO-gram for
each of the SNPA-addresses in the cache, effecting a broadcast to all
participating systems. Before passing an ISO-gram to the IP subnet
layer, the SNAcP prepends an SNAcP header to each outgoing ISO-gram.
This header will take the form:
SNAcP Header Format
Octet Value Meaning
--------------------------------------------------------
1 01 Version number
--------------------------------------------------------
2 Semantics of address:
00 Not a multicast address
01 All ESs
02 All ISs
03 Broadcast
--------------------------------------------------------
3,4 OSI checksum as defined in ISO 8473
The SNAcP header has three fields, a version number field, a
semantics field, and a checksum field. The version number will take
the value 01. The checksum field will take the two octet ISO
(Fletcher) checksum of the SNAcP header. The checksum algorithm is
described in ISO 8473.
The semantics field will take one of 4 values, indicating "all ESs",
"all ISs", "broadcast", or "not a multicast address". The value of
the semantics field is determined by a parameter passed to the SNAcP
by the calling OSI network entity. A participant in the experiment
may test the OSI network layer over a set of point-to-point links by
choosing not to use the multicast capabilities provided by the SNAcP
on the outgoing path.
On the incoming path, the SNAcP inspects the SNAcP header and decides
whether or not to accept the ISO-gram. If it accepts the ISO-gram,
the SNAcP removes the SNAcP header and passes the ISO-gram to the OSI
CLNL, otherwise, it discards the ISO-gram. The SNAcP will always
accept ISO-grams with SNAcP headers indicating "not a multicast
address" (value zero in the semantics field) and "broadcast" (value
03). Whether an SNAcP will accept ISO-grams for either of the two
multicast groups "all ESs" (value 1) and "all ISs" (value 2) will
depend on local configuration information. If the system on which
the SNAcP resides is configured as an end system, it will accept
ISO-grams destined for "all ESs" and if it is configured as an
intermediate system, it will accept ISO-grams destined for "all ISs".
A participant who is testing the OSI network layer over a set of
point-to-point links will accept ISO-grams according to these rules
as well.
Consideration was given to making the SNAcP extensible by making the
semantics and checksum fields variable-length parameters, in the
manner of ISO 8473. We feel that the presence of a version number
provides sufficient extensibility.
Errors on the IP subnet
The IP subnet layer may receive ICMP messages and may pass error
indications to the SNAcP layer as a result of having received these
ICMP messages. It is assumed that in this context, the IP subnet
will handle ICMP messages in the same way that it handles them in any
other context. For example, upon receipt of an ICMP echo message,
the IP subnet will respond with an ICMP echo reply, and the SNAcP
need not be informed of the receipt of the ICMP echo message.
Certain ICMP messages such as source quench are likely to produce an
error indication to all layers using the IP subnet. The actions
taken by the SNAcP for these indications is purely a local matter,
however the following actions are suggested.
Suggested SNAcP Actions in Response to
ICMP-related Error Indications
ICMP message type Action taken by the SNAcP
-----------------------------------------------------------
Destination unreachable, If the remote address is present
Parameter problem, in the cache of core systems'
Time exceeded addresses, mark it unusable.
Inform network management.
-----------------------------------------------------------
Source quench If the remote address is present
in the cache of core systems'
addresses, mark the remote
address as unusable and set a
timer for a time after which
the address becomes usable
again.
Inform network management.
-----------------------------------------------------------
All others Ignored by the SNAcP layer.
To "inform network management" may mean to print a message on the
system console, to inform a local process, to increment a counter, to
write a message in a log file, or it may mean to do nothing.
The effect of marking a cached address as unusable is as follows.
When the SNAcP attempts to broadcast or multicast an ISO-gram,
addresses in the cache that are marked as unusable are ignored. When
the SNAcP attempts to send a non-multicast ISO-gram to an unusable
cached address, the SNAcP returns an error indication to the OSI
CLNL. In this way, when the OSI CLNL uses the SNAcP to simulate a
set of point-to-point links, it is notified when a link fails, but
when the OSI CLNL uses the SNAcP to simulate a multicast subnet, it
is not notified when one system on the subnet goes down.
Use of UDP/IP in Lieu of IP
In addition to using IP directly, for testing purposes it may be
useful to support the OSI CLNL over the User Datagram Protocol (UDP).
This is because some implementors do not have direct access to IP,
but do have access to the UDP. For example, an implementor may have
an a binary license for an operating system that provides TCP/IP and
UDP/IP, but no direct access to IP. These implementors may
participate in a parallel experiment, called EON-UDP, by using UDP/IP
as a subnetwork instead of using the IP subnet. In this case, the
OSI NPDU (after fragmentation, if applicable) will be placed in the
data portion of a UDP datagram. UDP port 147 (decimal) has been
assigned for this purpose. These participants will place an SNAcP
between UDP and ISO 8473 rather than between IP and ISO 8473. In all
other respects, the EON-UDP experiment is identical to the EON
experiment.
Of course, network layers entities using the UDP/IP subnet will not
interoperate directly with network layers entities using the IP
subnet. The procedures proposed in this memo do not prevent an
implementor from building an EON to EON-UDP gateway, however the
issues related to building and routing to such a gateway are not
addressed in this memo. This memo simply proposes two distinct
parallel experiments for two groups of experimenters having different
resources.
The preferred method of experimentation is to use the IP subnet, in
other words, EON. The EON-UDP variant is intended for use only by
those who cannot participate in EON.
Dissemination of Topological Information and Host Names
The EON experiment simulates a logical topology that is not as
connected as the underlying logical topology offered by the Internet.
The topology of the IP subnet is, in effect, simulated by the SNAcP
layer in each of the core systems. Each of the core systems caches a
list of the other core systems in the EON. When a system boots, it
needs some initial list of the participating core systems. For this
reason, a list of core systems will be maintained by the IANA.
In addition, a list of all participating ESs will be maintained by
the IANA. This list is not necessary for the functioning of the EON
network layer. It is a convenience to the experimenters, and is
meant for use by application layer software or human users.
Two pairs of lists are kept, one for the EON and one for EON-UDP.
core.EON This is a list of SNPA-addresses of those systems
that will be (logically) reachable via the IP subnet
in one ISO 8473-hop from any other core system. This
does not mean that systems in this file are gateways
or ISs. They may be ESs, ISs or both. A site may
participate as a core system before its address is
included in this file and distributed to other core
systems, but under these circumstances other core systems
will not know to send configuration messages (ESHs and
ISHs) to the new site when coming up or rebooting. The
SNPA-addresses in this file will be ASCII strings of
the form A.B.C.D, no more than one per line.
White space (tabs, blanks) will be optional before
A and after D. A pound-sign (#) will indicate that
it and everything following it on that line is a comment.
For example:
128.105.2.153 # bounty.cs.wisc.edu
core.EON-UDP
This is the equivalent of core.EON for use with
the UDP/IP subnet. The format is the same that of
core.EON.
hosts.EON This is a list of the ASCII host names of all end
systems participating in the IP subnet experiment,
one host name per line. It is not used by the OSI
CLNL.
hosts.EON-UDP
This is a list of the ASCII host names of all end
systems participating in the UDP/IP subnet experiment,
one host name per line. It is meant for the use of
applications. It is not used by the OSI CLNL.
The files will be available from the IANA via anonymous ftp. Sites
wishing to join the experimental OSI internet will have to have their
host names and core system addresses added to the appropriate files.
They may do so by sending requests to Joyce K. Reynolds at the
electronic mail address:
JKREY@ISI.EDU
Hypothetical EON Topology
Figure 1 describes the logical links in a hypothetical topology, in
which three university computer sciences departments are
participating in the experiment: the University of Wisconsin (U of
W), the University of Tudor (U of Tudor), and the University of
Fordor (U of Fordor). The U of W has two local area networks(LANs),
128.105.4 and 128.105.2, and four systems that are acting as ESs in
the experiment. Two systems are attached to both LANs. Only one of
these two systems is forwarding ISO-grams, in other words, acting as
an IS. The U of Tudor has only one participating system, and it is
acting as an ES. The U of Fordor has two systems that are
participating in the experiment, one of which is an IS only, and the
other of which is acting as an ES only.
The contents of the core.EON and hosts.EON files for this topology
are shown below.
#
# core.EON for hypothetical EON topology
#
128.105.2.153 # IS/ES in cs.wisc.edu
26.5.0.73 # ES in cs.tudor.edu
192.5.2.1 # IS in cs.fordor.edu
#
# hosts.EON hypothetical EON topology
#
128.105.4.150 # ES in cs.wisc.edu
128.105.2.150 # same as above : multihomed ES
128.105.4.154 # ES in cs.wisc.edu
128.105.4.151 # ES in cs.wisc.edu
128.105.2.153 # IS/ES in cs.wisc.edu
26.5.0.73 # ES in cs.tudor.edu
192.5.2.2 # ES in cs.fordor.edu
______U of WI (128.105)______
( )
( 128.105.4 )
( | ) _U of Tudor__
( | 128.105.2.150 ) ( )
( | 128.105.4.150 ) ( )
( |------ES-----------| ) ( ES )
( | | ) ( 26.5.0.73 )
( | | ) ( | )
( | | ) (___|_________)
( | | ) |
( | | ) -------------
( |---ES | ) _|_
( | 128.105.4.154 | ) ( )
( | | ) ( )
( | | ) ( IP )
( | |----------( subnet )
( | | ) ( )
( | | ) ( )
( | | ) (___)
( |---ES | ) |
( | 128.105.4.151 | ) -------------
( | | ) |
( | | ) _U of Fordor_
( | | ) ( | )
( |---IS/ES-----------| ) ( | )
( 128.105.2.153 | ) ( IS )
( 128.105.4.153 | ) ( 192.5.2.1 )
( | ) ( | )
( | ) ( | )
( 128.105.2 ) ( ES )
( ) ( 192.5.2.2 )
(_____________________________) (_____________)
Figure 1: Hypothetical EON Topology
The U of Fordor system 192.5.2.1 may, in addition to acting as an IS,
begin acting as an ES at any time, by participating in the ES-IS
protocol as an ES and by beginning to serve a set of NSAPs. It may
act as an ES or as an IS or as both. In fact, the U of Fordor
systems 192.5.2.1 and 192.5.2.2 could reverse roles at any time,
regardless of their physical connectivity to the Internet, merely by
modifying their use of the ES-IS protocol and by their serving or not
serving NSAPs. Suppose that these two systems reverse roles:
192.5.2.1 becomes an ES, not a core system, and 192.5.2.2 becomes a
core system and an IS. Suppose further that the experimenters at the
U of Fordor do not inform the IANA of the change immediately, so the
core.EON file is out-of-date for a while. The effect will be that
other core systems will continue to send configuration messages to
192.5.2.1, which will respond as an ES, not as an IS, and it will
appear that 192.5.2.2 is not reachable from the rest of the topology
because the other core systems will not know to send configuration
information to it. However, when 192.5.2.2 is booted, it will send
configuration messages to all core systems informing them of its
existence via the IS-IS protocol. Those core systems that are acting
as ISs will respond with their configuration messages, update their
core system caches, thereby establishing a set of logical links
between 192.5.2.2 and the rest of the core systems.
Relationship of this Memo to other RFCs
RFCs 1006 and 983
ISO Transport Services on top of the TCP. Whereas RFCs 1006 and
983 offer a means of running the OSI session layer protocol and
higher OSI layers over TCP/IP, this memo provides a means of
running the OSI network and transport layers on an IP
internetwork.
RFC 1069
Guidelines for the use of Internet-IP addresses in the ISO
Connectionless-Mode Network Protocol. RFC 1069 suggests a method
to use the existing Internet routing and addressing in a gateway
that forwards ISO connectionless network layer protocol datagrams.
In contrast, this memo suggests a method to use the ISO routing
and addressing in a gateway that forwards ISO connectionless
network layer protocol datagrams.
RFC 982
ANSI Working Document X3S3.3/85-258. This is a set of guidelines
for specifying the structure of the DSP part of an ISO address.
The addresses described in this memo meet the guidelines set forth
in RFC 982.
References
Plummer, D., "An Ethernet Address Resolution Protocol - or -
Converting Network Protocol Addresses to 48.bit Ethernet Address
for Transmission on Ethernet Hardware", RFC 826, MIT, November
1982.
Finlayson, R., T. Mann, J. Mogul, and M. Theimer, "A Reverse
Address Resolution Protocol", RFC 903, Stanford, June 1984.
Postel, J., "Internet Protocol - DARPA Internet Program Protocol
Specification", RFC 791, DARPA, September 1981.
Postel, J., "Internet Control Message Protocol - DARPA Internet
Program Protocol Specification", RFC 792, ISI, September 1981.
Postel, J., "User Datagram Protocol", RFC 768, ISI, August 1980.
ISO, "Protocol For Providing the Connectionless Mode Network
Service", (ISO 8473), March 1986. (This is also published as RFC
994.)
ISO, "End System to Intermediate System Routing Exchange Protocol
for Use in Conjunction with the Protocol for the Provision of the
Connectionless-mode Network Service (ISO 8473)", (ISO DP 9542).
(This is also published as RFC 995.)
ISO, "Intermediate System to Intermediate System Intra-Domain
Routing Exchange Protocol", (ISO TC 97/SC 6/N xxxx).
OSI, "OSI Routing Framework", (PD TR 97/SC 6/N 9575).
Authors' Addresses
Robert A. Hagens
Computer Sciences Department
University of Wisconsin - Madison
1210 West Dayton Street
Madison, WI 53706
608/ 262-1017
EMail: hagens@cs.wisc.edu
Nancy E. Hall
Computer Sciences Department
University of Wisconsin - Madison
1210 West Dayton Street
Madison, WI 53706
608/ 262-5945
EMail: nhall@cs.wisc.edu
Marshall T. Rose
The Wollongong Group
San Antonio Blvd.
Palo Alto, California
415/ 962-7100
Email: mrose@twg.com
Comments and Suggestions
Please direct comments, suggestions, and indications of desire to
participate to the authors.