draft-ietf-pana-requirements-00.txt   draft-ietf-pana-requirements-01.txt 
Internet Engineering Task Force Alper E. Yegin (Editor) PANA Working Group Alper E. Yegin, Editor
Internet Draft Yoshihiro Ohba INTERNET-DRAFT Yoshihiro Ohba
draft-ietf-pana-requirements-00.txt Reinaldo Penno Date: March 2002 Reinaldo Penno
Expires: August 3, 2002 George Tsirtsis Expires: September 2002 George Tsirtsis
Cliff Wang Cliff Wang
February 3, 2002
Protocol for Carrying Authentication for Protocol for Carrying Authentication for
Network Access (PANA) Network Access (PANA)
Requirements and Terminology Requirements and Terminology
<draft-ietf-pana-requirements-01.txt>
Status of this Memo Status of this Memo
This document is an Internet-Draft and is in full conformance This document is an Internet-Draft and is in full conformance
with all provisions of Section 10 of RFC2026. with all provisions of Section 10 of RFC2026.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet- other groups may also distribute working documents as Internet-
Drafts. Drafts.
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The list of Internet-Draft Shadow Directories can be accessed at The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html. http://www.ietf.org/shadow.html.
Abstract Abstract
It is expected that future IP devices will have a variety of access It is expected that future IP devices will have a variety of access
technologies to gain network connectivity. Currently there are technologies to gain network connectivity. Currently there are
access-specific mechanisms for providing client information to the access-specific mechanisms for providing client information to the
network for authentication and authorization purposes. In addition network for authentication and authorization purposes. In addition
to being limited to specific access medias (e.g., 802.1x for IEEE to being limited to specific access media (e.g., 802.1x for IEEE 802
802 links), some of these protocols are also sub-optimal (e.g., PPP links), some of these protocols are limited to specific network
due to its mandatory framing which is not always needed). The goal topologies (e.g., PPP for point-to-point links). The goal of the
of the PANA Working Group is to design a general network-layer PANA Working Group is to design a general network-layer protocol to
protocol to authenticate clients to the networks. The protocol will authenticate clients to the networks. The protocol will run between
run between a client's device and an agent device in the network a client's device and an agent device in the network where the agent
where the agent might be a client of the AAA infrastructure. The might be a client of the AAA infrastructure. The protocol should be
protocol should be independent of the underlying access-type and not independent of the underlying access-type and not be limited to
overloaded with other aspects of the network access (e.g., framing). specific network topologies. This document defines the common
This document defines the common terminology and identifies the terminology and identifies the requirements for PANA.
requirements for PANA.
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Table of Contents Table of Contents
Status of this Memo................................................1
Abstract...........................................................1 Status of this Memo...............................................1
1. Introduction....................................................3 Abstract..........................................................1
2. Key Words.......................................................4 Table of Contents.................................................2
3. Terminology.....................................................4 1. Introduction...................................................2
4. Requirements....................................................4 2. Key Words......................................................3
4.1. Authentication................................................4 3. Terminology....................................................4
4.1.1. Authentication of Client....................................4 4. Requirements...................................................4
4.1.2. Authorization, Accounting and Access Control................5 4.1. Authentication...............................................4
4.1.3. Authentication Backend......................................5 4.1.1. Authentication of Client...................................4
4.1.4. Re-authentication...........................................5 4.1.2. Authorization, Accounting and Access Control...............5
4.1.5. Mutual Authentication.......................................6 4.1.3. Authentication Backend.....................................5
4.1.6. Identifiers.................................................6 4.1.4. Identifiers................................................5
4.2. Network.......................................................6 4.2. Network......................................................6
4.2.1. Multi-access................................................6 4.2.1. Multi-access...............................................6
4.2.2. Disconnect Indication.......................................6 4.2.2. Disconnect Indication......................................6
4.2.3. Location of PAA.............................................6 4.2.3. Location of PAA............................................6
4.3. Interaction with Other Protocols..............................6 4.2.4. Secure Channel.............................................6
4.4. Performance...................................................7 4.3. Interaction with Other Protocols.............................6
4.5. Miscellaneous.................................................7 4.4. Performance..................................................7
4.5.1. IP Version Independence.....................................7 4.5. Reliability and Congestion Control...........................7
4.5.2. Reliability and Congestion..................................7 4.6. Miscellaneous................................................7
4.5.3. Denial of Service Attacks...................................7 4.6.1. IP Version Independence....................................7
Acknowledgements...................................................7 4.6.2. Denial of Service Attacks..................................7
References.........................................................8 4.6.3. Location Privacy...........................................7
AuthorsĂ Addresses.................................................9 Acknowledgements..................................................7
Full Copyright Statement..........................................10 References........................................................8
AuthorsĂ Addresses................................................9
Full Copyright Statement.........................................10
1. Introduction 1. Introduction
Currently there are a variety of access technologies available to Currently there are a variety of access technologies available to
the network clients. While most of the clients currently have single the network clients. While most of the clients currently have single
interface, it is expected that in the future they will have multiple interface, it is expected that in the future they will have multiple
interfaces of different types to access the network. interfaces of different types to access the network.
An authentication mechanism is needed in order to provide secure An authentication mechanism is needed in order to provide secure
network access to the legitimate clients. Some of the current network access to the legitimate clients. Some of the current
authentication mechanisms are access technology specific. For authentication mechanisms are access technology specific. For
example 802.1x [8021X] only works for IEEE 802 link layers. If a example 802.1x [8021X] works for only IEEE 802 link layers. If a
client can have more than one type of interface, using access- client can have more than one type of interface, using access-
specific authentication mechanisms leads to running a collection of specific authentication mechanisms leads to running a collection of
protocols on the client for the same purpose. It is clearly protocols on the client for the same purpose. It is clearly
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advantageous to use a general protocol to authenticate the client advantageous to use a general protocol to authenticate the client
for network access on any type of technology. for network access on any type of technology.
The most widely used protocol for authenticating clients is the PPP The most widely used protocol for authenticating clients is the PPP
[PPP]. This protocol can run on various access types, but it is not [PPP]. This protocol can run on various access types, but it
limited to authenticating the clients. It also provides mandatory provides an inherently point-to-point interface. While it can
PPP framing. Since framing is already supported by certain link efficiently be applied to such topologies, using PPP with a multi-
types, having to use this extra framing creates sub-optimal network access network creates sub-optimal solutions. Such multi-access
access solutions. networks require either a full mesh of PPP links among clients, or a
designated router as the end-point of PPP links.
There is currently no general protocol to be used by a client for There is currently no general protocol to be used by a client for
gaining network access, and the PANA Working Group will attempt to gaining network access, and the PANA Working Group will attempt to
fill that hole. The Working Group will design a protocol between a fill that hole. The Working Group will design a protocol between a
client's device and an agent device in the network where the agent client's device and an agent device in the network where the agent
might be a client of the AAA infrastructure. As a network-layer might be a client of the AAA infrastructure. As a network-layer
protocol, it will be independent of the underlying access protocol, it will be independent of the underlying access
technologies. The protocol design will also be limited to defining a technologies. It will also be applicable to any network topology.
messaging protocol (i.e., a carrier) for providing the clients'
information to the network for authentication and authorization
purposes. It will not deal with the other aspects of network access
such as framing.
The Working Group will not invent new security protocols and The protocol design will be limited to defining a messaging protocol
mechanisms but instead will use the existing mechanisms. In (i.e., a carrier) for providing the clients' information to the
particular, the Working Group will not define authentication network for authentication and authorization purposes. The Working
protocols, key distribution or key agreement protocols, or key Group will not invent new security protocols and mechanisms but
derivation. The desired protocol can be viewed as the front-end of instead will use the existing mechanisms. In particular, the Working
the AAA protocol or any other protocol/mechanisms the network is Group will not define authentication protocols, key distribution or
running at the background to authenticate its clients. It will act key agreement protocols, or key derivation. The desired protocol can
as a carrier for an already defined security protocol or mechanism. be viewed as the front-end of the AAA protocol or any other
protocol/mechanisms the network is running at the background to
authenticate its clients. It will act as a carrier for an already
defined security protocol or mechanism.
As an example, Mobile IP Working Group has already defined such a As an example, Mobile IP Working Group has already defined such a
carrier for Mobile IPv4 [MIPV4]. Mobile IPv4 registration request carrier for Mobile IPv4 [MIPV4]. Mobile IPv4 registration request
message is used as the carrier for authentication extensions (MN-FA message is used as the carrier for authentication extensions (MN-FA
[MIPV4], or MN-AAA [MNAAA]) to receive forwarding service from the [MIPV4], or MN-AAA [MNAAA]) to receive forwarding service from the
foreign agents. In that sense, designing the equivalent of Mobile foreign agents. In that sense, designing the equivalent of Mobile
IPv4 registration request messages for general network access is the IPv4 registration request messages for general network access is the
goal of this work, but not defining the equivalent of MN-FA or MN- goal of this work, but not defining the equivalent of MN-FA or MN-
AAA extensions. AAA extensions.
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requirements of a protocol for PANA. These terminology and requirements of a protocol for PANA. These terminology and
requirements will be used to define and limit the scope of the work requirements will be used to define and limit the scope of the work
to be done in this group. to be done in this group.
2. Key Words 2. Key Words
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [KEYWORDS]. document are to be interpreted as described in [KEYWORDS].
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3. Terminology 3. Terminology
Device Identifier (DI) Device Identifier (DI)
The identifier used by the network as a handle to control and The identifier used by the network as a handle to control and
police the network access of a client. Depending on the access police the network access of a client. Depending on the access
technology, identifier might contain any of IP address, link- technology, identifier might contain any of IP address, link-
layer address, switch port number, etc. of a device. PANA layer address, switch port number, etc. of a device. PANA
authentication agent keeps a table for binding device authentication agent keeps a table for binding device
identifiers to the PANA clients. At most one PANA client identifiers to the PANA clients. At most one PANA client
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PANA MUST NOT define new security protocols or mechanisms. Instead PANA MUST NOT define new security protocols or mechanisms. Instead
it must be defined as a "carrier" for such protocols. PANA MUST it must be defined as a "carrier" for such protocols. PANA MUST
identify which specific security protocol(s) or mechanism(s) it can identify which specific security protocol(s) or mechanism(s) it can
carry (the "payload"). An example of a carrier would be the carry (the "payload"). An example of a carrier would be the
registration request message of Mobile IPv4 [MIPV4] that carries MN- registration request message of Mobile IPv4 [MIPV4] that carries MN-
FA authentication extension. FA authentication extension.
Authentication and encryption of data traffic sent to and from an Authentication and encryption of data traffic sent to and from an
authenticated PaC is outside the scope of PANA. Providing a complete authenticated PaC is outside the scope of PANA. Providing a complete
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secure network access solution by also securing router discovery secure network access solution by also securing router discovery
[RDISC], neighbor discovery [NDISC], and address resolution [RDISC], neighbor discovery [NDISC], and address resolution
protocols [ARP] is outside the scope as well. protocols [ARP] is outside the scope as well.
Both the PaC and the PAA MUST be able to authenticate each other for
network access. Providing capability of only PAA authenticating the
PaC is not sufficient.
PANA MUST be capable of carrying out both periodic and on-demand re-
authentication. Both the PaC and the PAA MUST be able to initiate
both the initial authentication and the re-authentication process.
When the DI is carried explicitly as part of the PANA payload, the
authentication computation MUST also include this field to provide
integrity protection for the DI. When the DI is carried implicitly
as the source of the PANA message, the protocol has to make sure
that the DI's integrity is protected by some other means (e.g.,
physical verification of incoming port number of the PANA message in
the case of switch port number as a DI and PAA co-located with the
link-layer access device). Protecting PaCs against DI theft is
outside the scope of PANA.
4.1.2. Authorization, Accounting and Access Control 4.1.2. Authorization, Accounting and Access Control
In addition to carrying authentication information, PANA MUST also In addition to carrying authentication information, PANA MUST also
carry a binary result (i.e., success or failure) of authorization carry a binary result (i.e., success or failure) of authorization
for network access to the PaC. Providing finer granularity for network access to the PaC. Providing finer granularity
authorization is outside the scope of PANA. authorization is outside the scope of PANA.
Providing access control functionality in the network is outside the Providing access control functionality in the network is outside the
scope of PANA. PAA MAY communicate the DI associated with a PaC to scope of PANA. PAA MAY communicate the DI associated with a PaC to
other entities in the network to setup packet filters and access other entities in the network to setup access control and accounting
control state. This interaction is outside the scope of PANA as state. This interaction is outside the scope of PANA as well.
well.
Carrying accounting data is outside the scope of PANA. Carrying accounting data is outside the scope of PANA.
4.1.3. Authentication Backend 4.1.3. Authentication Backend
PAA MAY use either a AAA backend, some other mechanism or a local PAA MAY use either a AAA backend, some other mechanism or a local
database to authenticate the PaC. PANA protocol MUST NOT make any database to authenticate the PaC. PANA protocol MUST NOT make any
assumptions on the backend authentication protocol or mechanisms. assumptions on the backend authentication protocol or mechanisms.
The interaction between the PAA and the backend authentication The interaction between the PAA and the backend authentication
entities is outside the scope of PANA. entities is outside the scope of PANA.
4.1.4. Re-authentication 4.1.4. Identifiers
PANA MUST be capable of carrying out both periodic and on-demand re-
authentication. Both the PaC and the PAA MUST be able to initiate
both the initial authentication and the re-authentication process.
4.1.5. Mutual Authentication
Both the PaC and the PAA MUST be able to authenticate each other for
network access. Providing capability of only PAA authenticating the
PaC is not sufficient.
4.1.6. Identifiers
PANA SHOULD allow various types of identifiers to be used for the PANA SHOULD allow various types of identifiers to be used for the
PaC (e.g., NAI, IP address, FQDN, etc.) PaC (e.g., NAI, IP address, FQDN, etc.)
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PANA SHOULD allow various types of identifiers to be used as the DI PANA SHOULD allow various types of identifiers to be used as the DI
(IP address, link-layer address, port number of a switch, etc.) (IP address, link-layer address, port number of a switch, etc.)
PAA MUST be able to create a binding between the PaC and the PAA MUST be able to create a binding between the PaC and the
associated DI upon successful PANA exchange. This binding is used associated DI upon successful PANA exchange. The DI MUST be carried
for access control and accounting in the network as described either explicitly as part of the PANA payload, or implicitly as the
in section 4.1.2. source of the PANA message, or both. This binding is used for access
control and accounting in the network as described in section 4.1.2.
4.2. Network 4.2. Network
4.2.1. Multi-access 4.2.1. Multi-access
Protocol MUST support PaCs with multiple interfaces, and networks Protocol MUST support PaCs with multiple interfaces, and networks
with multiple routers on multi-access links. with multiple routers on multi-access links.
4.2.2. Disconnect Indication 4.2.2. Disconnect Indication
PANA MUST NOT assume connection-oriented links. Links may or may not PANA MUST NOT assume connection-oriented links. Links may or may not
provide disconnect indication. PANA SHOULD define a "disconnect" provide disconnect indication. PANA SHOULD define a "disconnect"
indication to allow PaCs to notify the PAA of their departure from indication to allow PaCs to notify the PAA of their departure from
the network. A similar indication SHOULD also be used to let PAA the network. A similar indication SHOULD also be used to let PAA
notify a PaC about the discontinuation of the network access. Access notify a PaC about the discontinuation of the network access. Access
discontinuation can happen due to various reasons such as network discontinuation can happen due to various reasons such as network
systems going down, or a change in access policy. systems going down, or a change in access policy.
4.2.3. Location of PAA 4.2.3. Location of PAA
PAA MAY be one or more hop away from the PaC. PAA MAY be one or more hop away from the PaC. PANA MUST define a
method used by PaCs for locating the PAAs in a network.
4.2.4. Secure Channel
PANA MUST not assume a secure channel between the PaC and the PAA.
PANA MUST be able to provide authentication especially in networks
which are not protected against eavesdropping and spoofing. PANA
MUST provide protection against replay attacks on both PaCs and
PAAs.
4.3. Interaction with Other Protocols 4.3. Interaction with Other Protocols
PANA MUST NOT handle mobility management of the PaC. But, it MUST be Mobility management is outside the scope of PANA. Though, PANA MUST
able to co-exist and not interfere with various mobility management be able to co-exist and not interfere with various mobility
protocols, such as Mobile IPv4 [MIPV4], Mobile IPv6 [MIPV6], fast management protocols, such as Mobile IPv4 [MIPV4], Mobile IPv6
handover protocols [FMIPV4, FMIPV6], and other standard protocols [MIPV6], fast handover protocols [FMIPV4, FMIPV6], and other
like IPv6 stateless address auto-configuration [ADDRCONF] (including standard protocols like IPv6 stateless address auto-configuration
privacy extensions [PRIVACY]), and DHCP [DHCP]. It MUST NOT make any [ADDRCONF] (including privacy extensions [PRIVACY]), and DHCP
assumptions on the protocols or mechanisms used for IP address
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[DHCP]. It MUST NOT make any assumptions on the protocols or
mechanisms used for IP address configuration of the PaC.
4.4. Performance 4.4. Performance
PANA design SHOULD give consideration to efficient handling of PANA design SHOULD give consideration to efficient handling of
authentication process. This is important for gaining network access authentication process. This is important for gaining network access
with minimum latency. As an example, a method like minimizing the with minimum latency. As an example, a method like minimizing the
protocol signaling by creating local security associations can be protocol signaling by creating local security associations can be
used for this purpose. used for this purpose.
4.5. Miscellaneous 4.5. Reliability and Congestion Control
4.5.1. IP Version Independence
PANA MUST work for both IPv4 and IPv6.
4.5.2. Reliability and Congestion
PANA MUST provide reliability and congestion control. It can do so PANA MUST provide reliability and congestion control. It can do so
by using techniques like re-transmissions, cyclic redundancy check, by using techniques like re-transmissions, cyclic redundancy check,
delayed initialization and exponential back-off. delayed initialization and exponential back-off.
4.5.3. Denial of Service Attacks 4.6. Miscellaneous
4.6.1. IP Version Independence
PANA MUST work for both IPv4 and IPv6.
4.6.2. Denial of Service Attacks
PANA MUST be robust against a class of DoS attacks such as blind PANA MUST be robust against a class of DoS attacks such as blind
masquerade attacks through IP spoofing that swamp the PAA in masquerade attacks through IP spoofing that swamp the PAA in
spending much resources and prevent legitimate clientsĂ attempts of spending much resources and prevent legitimate clientsĂ attempts of
network access. The required robustness is no worse than that for network access. The required robustness is no worse than that for
TCP SYN attack. TCP SYN attack.
4.6.3. Location Privacy
Location privacy is outside the scope of PANA.
Acknowledgements Acknowledgements
We would like to thank Basavaraj Patil and Subir Das for their We would like to thank Basavaraj Patil, Subir Das, and the PANA
valuable contributions to the discussions and preparation of this Working Group members for their valuable contributions to the
document. discussions and preparation of this document.
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References References
[KEYWORDS] S. Bradner, "Key words for use in RFCs to Indicate [KEYWORDS] S. Bradner, "Key words for use in RFCs to Indicate
Requirement Levels", RFC 2119, March 1997. Requirement Levels", RFC 2119, March 1997.
[8021X] ˘IEEE Standards for Local and Metropolitan Area Networks: [8021X] "IEEE Standards for Local and Metropolitan Area Networks:
Port Based Network Access Control÷, IEEE Draft 802.1X/D11, March Port Based Network Access Control", IEEE Draft 802.1X/D11, March
2001. 2001.
[PPP] W. Simpson (editor), "The Point-To-Point Protocol (PPP)", STD [PPP] W. Simpson (editor), "The Point-To-Point Protocol (PPP)", STD
51, RFC 1661, July 1994. 51, RFC 1661, July 1994.
[MIPV4] C. Perkins (editor), ˘IP Mobility Support÷, RFC 2002, [MIPV4] C. Perkins (editor), "IP Mobility Support", RFC 2002,
October 1996. October 1996.
[MIPV6] D. Johnson and C. Perkins, "Mobility Support in IPv6", [MIPV6] D. Johnson and C. Perkins, "Mobility Support in IPv6",
draft-ietf-mobileip-ipv6-15.txt, July 2001. draft-ietf-mobileip-ipv6-15.txt, July 2001. Work in progress.
[MNAAA] C. Perkins, P. Calhoun, ˘Mobile IPv4 Challenge/Response [MNAAA] C. Perkins, P. Calhoun, "Mobile IPv4 Challenge/Response
Extensions÷, RFC3012, November 2000. Extensions", RFC3012, November 2000.
[RDISC] S. Deering, "ICMP Router Discovery Messages", RFC 1256, [RDISC] S. Deering, "ICMP Router Discovery Messages", RFC 1256,
September 1991. September 1991.
[NDISC] T. Narten, E. Nordmark, and W. Simpson, ˘Neighbor Discovery [NDISC] T. Narten, E. Nordmark, and W. Simpson, "Neighbor Discovery
for IP Version 6 (IPv6)÷,RFC 2461, December 1998. for IP Version 6 (IPv6)",RFC 2461, December 1998.
[ARP] D. Plummer, "An Ethernet Address Resolution Protocol", STD [ARP] D. Plummer, "An Ethernet Address Resolution Protocol", STD 37,
37, RFC 826, November 1982. RFC 826, November 1982.
[FMIPV4] K. ElMalki (editor), et. al., "Low latency Handoffs in [FMIPV4] K. ElMalki (editor), et. al., "Low latency Handoffs in
Mobile IPv4", draft-ietf-mobileip-lowlatency-handoffs-v4-03, Mobile IPv4", November 2001. Work in progress.
November 2001.
[FMIPV6] G. Dommety (editor), et. al., "Fast Handovers for Mobile [FMIPV6] G. Dommety (editor), et. al., "Fast Handovers for Mobile
IPv6", draft-ietf-mobileip-fast-mipv6-03.txt, July 2001. IPv6", July 2001. Work in progress.
[DHCP] R. Droms (editor), et. al., ˘Dynamic Host Configuration [DHCP] R. Droms (editor), et. al., "Dynamic Host Configuration
Protocol for IPv6÷, draft-ietf-dhc-dhcpv6-22.txt, December 2001. Protocol for IPv6", December 2001. Work in progress.
[PRIVACY] T. Narten, R. Draves, ˘Privacy Extensions for Stateless [PRIVACY] T. Narten, R. Draves, "Privacy Extensions for Stateless
Address Autoconfiguration in IPv6÷, RFC 3041, January 2001. Address Autoconfiguration in IPv6", RFC 3041, January 2001.
AuthorsĂ Addresses Yegin (Editor), et.al. Expires Sep 2002 [Page 8]
Authors' Addresses
Alper E. Yegin Alper E. Yegin
DoCoMo USA Labs DoCoMo USA Labs
181 Metro Drive, Suite 300 181 Metro Drive, Suite 300
San Jose, CA, 95110 San Jose, CA, 95110
USA USA
Phone: +1 408 451 4743 Phone: +1 408 451 4743
Email: alper@docomolabs-usa.com Email: alper@docomolabs-usa.com
Yoshihiro Ohba Yoshihiro Ohba
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E-mail: G.Tsirtsis@Flarion.com, gtsirt@hotmail.com E-mail: G.Tsirtsis@Flarion.com, gtsirt@hotmail.com
Cliff Wang Cliff Wang
Smart Pipes Smart Pipes
565 Metro Place South 565 Metro Place South
Dublin, OH, 43017 Dublin, OH, 43017
USA USA
Phone: +1 614 923 6241 Phone: +1 614 923 6241
Email: cwang@smartpipes.com Email: cwang@smartpipes.com
Yegin (Editor), et.al. Expires Sep 2002 [Page 9]
Full Copyright Statement Full Copyright Statement
"Copyright (C) The Internet Society (2001). All Rights Reserved. "Copyright (C) The Internet Society (2002). All Rights Reserved.
This document and translations of it may be copied and furnished to This document and translations of it may be copied and furnished to
others, and derivative works that comment on or otherwise explain it others, and derivative works that comment on or otherwise explain it
or assist in its implementation may be prepared, copied, published or assist in its implementation may be prepared, copied, published
and distributed, in whole or in part, without restriction of any and distributed, in whole or in part, without restriction of any
kind, provided that the above copyright notice and this paragraph kind, provided that the above copyright notice and this paragraph
are included on all such copies and derivative works. However, this are included on all such copies and derivative works. However, this
document itself may not be modified in any way, such as by removing document itself may not be modified in any way, such as by removing
the copyright notice or references to the Internet Society or other the copyright notice or references to the Internet Society or other
Internet organizations, except as needed for the purpose of Internet organizations, except as needed for the purpose of
developing Internet standards in which case the procedures for developing Internet standards in which case the procedures for
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The limited permissions granted above are perpetual and will not be The limited permissions granted above are perpetual and will not be
revoked by the Internet Society or its successors or assigns. revoked by the Internet Society or its successors or assigns.
This document and the information contained herein is provided on an This document and the information contained herein is provided on an
"AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
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