Network Working Group G. Mirsky
Internet-Draft ZTE Corp.
Intended status: Standards Track G. Jun
Expires: March 27, 2020 ZTE Corporation
H. Nydell
Accedian Networks
R. Foote
Nokia
September 24, 2019

Simple Two-way Active Measurement Protocol
draft-ietf-ippm-stamp-08

Abstract

This document describes a Simple Two-way Active Measurement Protocol which enables the measurement of both one-way and round-trip performance metrics like delay, delay variation, and packet loss.

Status of This Memo

This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79.

Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet-Drafts is at https://datatracker.ietf.org/drafts/current/.

Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress."

This Internet-Draft will expire on March 27, 2020.

Copyright Notice

Copyright (c) 2019 IETF Trust and the persons identified as the document authors. All rights reserved.

This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License.


Table of Contents

1. Introduction

Development and deployment of Two-Way Active Measurement Protocol (TWAMP) [RFC5357] and its extensions, e.g., [RFC6038] that defined Symmetrical Size for TWAMP provided invaluable experience. Several independent implementations of both TWAMP and TWAMP Light exist, have been deployed, and provide important operational performance measurements.

At the same time, there has been noticeable interest in using a more straightforward mechanism for active performance monitoring that can provide deterministic behavior and inherit separation of control (vendor-specific configuration or orchestration) and test functions. Recent work on IP Edge to Customer Equipment using TWAMP Light from Broadband Forum [BBF.TR-390] demonstrated that interoperability among implementations of TWAMP Light is challenged because the composition and operation of TWAMP Light were not sufficiently specified in [RFC5357]. According to [RFC8545], TWAMP Light includes sub-set of TWAMP-Test functions to provide comprehensive solution requires support by other applications that provide, for example, control and security.

This document defines an active performance measurement test protocol, Simple Two-way Active Measurement Protocol (STAMP), that enables measurement of both one-way and round-trip performance metrics like delay, delay variation, and packet loss. Some TWAMP extensions, e.g., [RFC7750] are supported by the extensions to STAMP base specification in [I-D.ietf-ippm-stamp-option-tlv].

2. Conventions used in this document

2.1. Terminology

STAMP - Simple Two-way Active Measurement Protocol

NTP - Network Time Protocol

PTP - Precision Time Protocol

HMAC Hashed Message Authentication Code

OWAMP One-Way Active Measurement Protocol

TWAMP Two-Way Active Measurement Protocol

MBZ May be Zero

2.2. Requirements Language

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here.

3. Operation and Management of Performance Measurement Based on STAMP

Figure 1 presents the Simple Two-way Active Measurement Protocol (STAMP) Session-Sender, and Session-Reflector with a measurement session. In this document, a measurement session also referred to as STAMP session, is the bi-directional packet flow between one specific Session-Sender and one particular Session-Reflector for a time duration. The configuration and management of the STAMP Session-Sender, Session-Reflector, and management of the STAMP sessions can be achieved through various means. Command Line Interface, OSS/BSS (operations support system/business support system as a combination of two systems used to support a range of telecommunication services) using SNMP or controllers in Software-Defined Networking using Netconf/YANG are but a few examples.

             
      o----------------------------------------------------------o
      |                      Configuration and                   |
      |                         Management                       |
      o----------------------------------------------------------o
             ||                                          ||
             ||                                          ||
             ||                                          ||
  +----------------------+                +-------------------------+
  | STAMP Session-Sender | <--- STAMP---> | STAMP Session-Reflector |
  +----------------------+                +-------------------------+
         
          

Figure 1: STAMP Reference Model

4. Theory of Operation

STAMP Session-Sender transmits test packets over UDP transport toward STAMP Session-Reflector. A STAMP Session-Sender MUST use UDP port 862 (TWAMP-Test Receiver Port) as the default destination UDP port number. A STAMP implementation of Session-Sender MUST be able to use UDP port numbers from User, a.k.a. Registered, Ports and Dynamic, a.k.a. Private or Ephemeral, Ports ranges defined in [RFC6335]. Before using numbers from the User Ports range, the possible impact on the network MUST be carefully studied and agreed by all users of the network domain where the test has been planned.

STAMP Session-Reflector receives Session-Sender's packet and acts according to the configuration and optional control information communicated in the Session-Sender's test packet. An implementation of STAMP Session-Reflector by default MUST use receive STAMP test packets on UDP port 862. An implementation of Session-Reflector that supports this specification MUST be able to define the port number to receive STAMP test packets from User Ports and Dynamic Ports ranges that are defined in [RFC6335]. STAMP defines two different test packet formats, one for packets transmitted by the STAMP-Session-Sender and one for packets transmitted by the STAMP-Session-Reflector.

STAMP supports two modes: unauthenticated and authenticated. Unauthenticated STAMP test packets, defined in Section 4.1.1 and Section 4.2.1, ensure interworking between STAMP and TWAMP Light as described in Section 4.5 packet formats.

By default, STAMP uses symmetrical packets, i.e., size of the packet transmitted by Session-Reflector equals the size of the packet received by the Session-Reflector.

4.1. Session-Sender Behavior and Packet Format

STAMP supports symmetrical test packets. The base STAMP Session-Sender packet has a minimum size of 44 octets in unauthenticated mode, see Figure 2, and 112 octets in the authenticated mode, see Figure 4. The variable length of a test packet in STAMP is supported by using Extra Padding TLV defined in [I-D.ietf-ippm-stamp-option-tlv].

4.1.1. Session-Sender Packet Format in Unauthenticated Mode

    
    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                        Sequence Number                        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                          Timestamp                            |
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |         Error Estimate        |                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               +
   |                                                               |
   |                                                               |
   |                         MBZ (30 octets)                       |
   |                                                               |
   |                                                               |
   |                                                               |
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Figure 2: STAMP Session-Sender test packet format in unauthenticated mode

         0                   1
         0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        |S|Z|   Scale   |   Multiplier  |
        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
          

Figure 3: Error Estimate Format

STAMP Session-Sender packet format in unauthenticated mode:

4.1.2. Session-Sender Packet Format in Authenticated Mode

    
  0                   1                   2                   3
  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                      Sequence Number                          |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                                                               |
 |                      MBZ (12 octets)                          |
 |                                                               |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                        Timestamp                              |
 |                                                               |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |        Error Estimate         |                               |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               +
 ~                                                               ~
 |                         MBZ (70 octets)                       |
 ~                                                               ~
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                                                               |
 |                       HMAC (16 octets)                        |
 |                                                               |
 |                                                               |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  

Figure 4: STAMP Session-Sender test packet format in authenticated mode

STAMP Session-Sender packet format in authenticated mode:

The field definitions are the same as the unauthenticated mode, listed in Section 4.1.1. Also, MBZ fields are used to align the packet on 16 octets boundary. The value of the field MAY be zeroed on transmission and MUST be ignored on receipt. Also, the packet includes a key-hashed message authentication code (HMAC) ([RFC2104]) hash at the end of the PDU. The detailed use of the HMAC field is described in Section 4.3.

4.2. Session-Reflector Behavior and Packet Format

The Session-Reflector receives the STAMP test packet, verifies it, prepares and transmits the reflected test packet.

Two modes of STAMP Session-Reflector characterize the expected behavior and, consequently, performance metrics that can be measured:

4.2.1. Session-Reflector Packet Format in Unauthenticated Mode

    
  0                   1                   2                   3
  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                        Sequence Number                        |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                          Timestamp                            |
 |                                                               |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |         Error Estimate        |           MBZ                 |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                          Receive Timestamp                    |
 |                                                               |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                 Session-Sender Sequence Number                |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                  Session-Sender Timestamp                     |
 |                                                               |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 | Session-Sender Error Estimate |           MBZ                 |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |Ses-Sender TTL |                    MBZ                        |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Figure 5: STAMP Session-Reflector test packet format in unauthenticated mode

For unauthenticated mode:

4.2.2. Session-Reflector Packet Format in Authenticated Mode

    
   0                   1                   2                   3
   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                        Sequence Number                        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                        MBZ (12 octets)                        |
   |                                                               |
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                          Timestamp                            |
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |         Error Estimate        |                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               +
   |                        MBZ (6 octets)                         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                        Receive Timestamp                      |
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                        MBZ (8 octets)                         |
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                 Session-Sender Sequence Number                |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                        MBZ (12 octets)                        |
   |                                                               |
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                 Session-Sender Timestamp                      |
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | Session-Sender Error Estimate |                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               +
   |                        MBZ (6 octets)                         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |Ses-Sender TTL |                                               |
   +-+-+-+-+-+-+-+-+                                               +
   |                                                               |
   |                        MBZ (15 octets)                        |
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                        HMAC (16 octets)                       |
   |                                                               |
   |                                                               |
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

  

Figure 6: STAMP Session-Reflector test packet format in authenticated mode

For the authenticated mode:

The field definitions are the same as the unauthenticated mode, listed in Section 4.2.1. Additionally, the MBZ field is used to align the packet on 16 octets boundary. The value of the field MAY be zeroed on transmission and MUST be ignored on receipt. Also, STAMP Session-Reflector test packet format in authenticated mode includes a key (HMAC) ([RFC2104]) hash at the end of the PDU. The detailed use of the HMAC field is in Section 4.3.

4.3. Integrity Protection in STAMP

To provide integrity protection, each STAMP message is being authenticated by adding Hashed Message Authentication Code (HMAC). STAMP uses HMAC-SHA-256 truncated to 128 bits (similarly to the use of it in IPSec defined in [RFC4868]); hence the length of the HMAC field is 16 octets. HMAC uses its own key, and the definition of the mechanism to distribute the HMAC key is outside the scope of this specification. One example is to use an orchestrator to configure HMAC key based on STAMP YANG data model [I-D.ietf-ippm-stamp-yang]. HMAC MUST be verified as early as possible to avoid using or propagating corrupted data.

4.4. Confidentiality Protection in STAMP

If confidentiality protection for STAMP is required, a STAMP test session MUST use a secured transport. For example, STAMP packets could be transmitted in the dedicated IPsec tunnel or share the IPsec tunnel with the monitored flow. Also, Datagram Transport Layer Security protocol would provide the desired confidentiality protection.

4.5. Interoperability with TWAMP Light

One of the essential requirements to STAMP is the ability to interwork with a TWAMP Light device. There are two possible combinations for such use case:

In the former case, the Session-Sender MAY not be aware that its Session-Reflector does not support STAMP. For example, a TWAMP Light Session-Reflector may not support the use of UDP port 862 as defined in [RFC8545]. Thus STAMP Session-Sender MAY use port numbers as defined in Section 4. If any of STAMP extensions are used, the TWAMP Light Session-Reflector will view them as Packet Padding field.

In the latter scenario, if a TWAMP Light Session-Sender does not support the use of UDP port 862, the test management system MUST set STAMP Session-Reflector to use UDP port number as defined in Section 4. If the TWAMP Light Session-Sender includes Packet Padding field in its transmitted packet, the STAMP Session-Reflector will return the reflected packet of the symmetrical size if the size of the received test packet is larger than the size of the STAMP base packet. The Session-Reflector MUST be set to use the default format for its timestamps, NTP.

STAMP does not support the Reflect Octets capability defined in [RFC6038]. If the Server Octets field is present in the TWAMP Session-Sender packet, STAMP Session-Reflector will not copy the content starting from the Server Octets field but will transmit the reflected packet of equal size.

5. Operational Considerations

STAMP is intended to be used on production networks to enable the operator to assess service level agreements based on packet delay, delay variation, and loss. When using STAMP over the Internet, especially when STAMP test packets are transmitted with the destination UDP port number from the User Ports range, the possible impact of the STAMP test packets MUST be thoroughly analyzed. The use of STAMP for each case MUST be agreed by users of nodes hosting the Session-Sender and Session-Reflector before starting the STAMP test session.

Also, the use of the well-known port number as the destination UDP port number in STAMP test packets transmitted by a Session-Sender would not impede the ability to measure performance in an Equal Cost Multipath environment and analysis in Section 5.3 [RFC8545] fully applies to STAMP.

6. IANA Considerations

This document doesn't have any IANA action. This section may be removed before the publication.

7. Security Considerations

[RFC5357] does not identify security considerations specific to TWAMP-Test but refers to security considerations identified for OWAMP in [RFC4656]. Since both OWAMP and TWAMP include control plane and data plane components, only security considerations related to OWAMP-Test, discussed in Sections 6.2, 6.3[RFC4656] apply to STAMP.

STAMP uses the well-known UDP port number allocated for the OWAMP-Test/TWAMP-Test Receiver port. Thus the security considerations and measures to mitigate the risk of the attack using the registered port number documented in Section 6 [RFC8545] equally apply to STAMP. Because of the control and management of a STAMP test being outside the scope of this specification only the more general requirement is set:

Use of HMAC-SHA-256 in the authenticated mode protects the data integrity of the STAMP test packets.

8. Acknowledgments

Authors express their appreciation to Jose Ignacio Alvarez-Hamelin and Brian Weis for their great insights into the security and identity protection, and the most helpful and practical suggestions. Also, our sincere thanks to David Ball and Rakesh Gandhi or their thorough reviews and helpful comments.

9. References

9.1. Normative References

[I-D.ietf-ippm-stamp-option-tlv] Mirsky, G., Xiao, M., Jun, G., Nydell, H., Foote, R. and A. Masputra, "Simple Two-way Active Measurement Protocol Optional Extensions", Internet-Draft draft-ietf-ippm-stamp-option-tlv-01, September 2019.
[IEEE.1588.2008] "Standard for a Precision Clock Synchronization Protocol for Networked Measurement and Control Systems", IEEE Standard 1588, March 2008.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997.
[RFC4656] Shalunov, S., Teitelbaum, B., Karp, A., Boote, J. and M. Zekauskas, "A One-way Active Measurement Protocol (OWAMP)", RFC 4656, DOI 10.17487/RFC4656, September 2006.
[RFC5357] Hedayat, K., Krzanowski, R., Morton, A., Yum, K. and J. Babiarz, "A Two-Way Active Measurement Protocol (TWAMP)", RFC 5357, DOI 10.17487/RFC5357, October 2008.
[RFC5905] Mills, D., Martin, J., Burbank, J. and W. Kasch, "Network Time Protocol Version 4: Protocol and Algorithms Specification", RFC 5905, DOI 10.17487/RFC5905, June 2010.
[RFC6038] Morton, A. and L. Ciavattone, "Two-Way Active Measurement Protocol (TWAMP) Reflect Octets and Symmetrical Size Features", RFC 6038, DOI 10.17487/RFC6038, October 2010.
[RFC6335] Cotton, M., Eggert, L., Touch, J., Westerlund, M. and S. Cheshire, "Internet Assigned Numbers Authority (IANA) Procedures for the Management of the Service Name and Transport Protocol Port Number Registry", BCP 165, RFC 6335, DOI 10.17487/RFC6335, August 2011.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017.
[RFC8186] Mirsky, G. and I. Meilik, "Support of the IEEE 1588 Timestamp Format in a Two-Way Active Measurement Protocol (TWAMP)", RFC 8186, DOI 10.17487/RFC8186, June 2017.
[RFC8545] Morton, A. and G. Mirsky, "Well-Known Port Assignments for the One-Way Active Measurement Protocol (OWAMP) and the Two-Way Active Measurement Protocol (TWAMP)", RFC 8545, DOI 10.17487/RFC8545, March 2019.

9.2. Informative References

[BBF.TR-390] "Performance Measurement from IP Edge to Customer Equipment using TWAMP Light", BBF TR-390, May 2017.
[I-D.ietf-ippm-stamp-yang] Mirsky, G., Xiao, M. and W. Luo, "Simple Two-way Active Measurement Protocol (STAMP) Data Model", Internet-Draft draft-ietf-ippm-stamp-yang-04, September 2019.
[RFC2104] Krawczyk, H., Bellare, M. and R. Canetti, "HMAC: Keyed-Hashing for Message Authentication", RFC 2104, DOI 10.17487/RFC2104, February 1997.
[RFC4868] Kelly, S. and S. Frankel, "Using HMAC-SHA-256, HMAC-SHA-384, and HMAC-SHA-512 with IPsec", RFC 4868, DOI 10.17487/RFC4868, May 2007.
[RFC7750] Hedin, J., Mirsky, G. and S. Baillargeon, "Differentiated Service Code Point and Explicit Congestion Notification Monitoring in the Two-Way Active Measurement Protocol (TWAMP)", RFC 7750, DOI 10.17487/RFC7750, February 2016.
[RFC8085] Eggert, L., Fairhurst, G. and G. Shepherd, "UDP Usage Guidelines", BCP 145, RFC 8085, DOI 10.17487/RFC8085, March 2017.

Authors' Addresses

Greg Mirsky ZTE Corp. EMail: gregimirsky@gmail.com
Guo Jun ZTE Corporation 68# Zijinghua Road Nanjing, Jiangsu 210012 P.R.China Phone: +86 18105183663 EMail: guo.jun2@zte.com.cn
Henrik Nydell Accedian Networks EMail: hnydell@accedian.com
Richard Foote Nokia EMail: footer.foote@nokia.com