PIM Working Group O. Komolafe Internet-Draft Arista Networks Intended status: Informational September 15, 2020 Expires: March 19, 2021 IGMPv3 and MLDv2 Survey Report draft-komolafe-pim-igmp-mld-survey-report-00 Abstract The PIM WG intends to progress IGMPv3 and MLDv2 from Proposed Standards to Internet Standards. The WG decided to conduct a survey of operators, vendors and implementors of these and related protocols to gather information about their implementation and deployment. This document presents the results of the survey and briefly summarizes the key findings. The survey indicates that there is widespread deployment and usage of of IGMPv3 and MLDv2, with numerous independent implementations interoperating successfully. No major issues with either protocol were identified and, similarly, no major unused features in the specifications were highlighted. These findings suggest that IGMPv3 and MLDv2 are indeed ready for progression to Internet Standards. 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 19, 2021. Copyright Notice Copyright (c) 2020 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 Komolafe Expires March 19, 2021 [Page 1] Internet-Draft IGMPv3 and MLDv2 Survey Report September 2020 (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 . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Approach . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2.1. Methodology . . . . . . . . . . . . . . . . . . . . . . . 3 3. Responses for Vendors or Host Implementors . . . . . . . . . 4 3.1. Protocols Implemented . . . . . . . . . . . . . . . . . . 4 3.2. Features Supported . . . . . . . . . . . . . . . . . . . 4 3.3. Issues Identified . . . . . . . . . . . . . . . . . . . . 4 3.4. Suggestions . . . . . . . . . . . . . . . . . . . . . . . 4 4. Responses for Network Operators . . . . . . . . . . . . . . . 5 4.1. Protocols Deployed . . . . . . . . . . . . . . . . . . . 5 4.2. Features Enabled . . . . . . . . . . . . . . . . . . . . 5 4.3. Interoperability Issues . . . . . . . . . . . . . . . . . 5 4.4. Fallback Mechanism . . . . . . . . . . . . . . . . . . . 5 4.5. Strengths and Weaknesses of IGMPv3 and MLDv2 . . . . . . 5 5. Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . 6 6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 6 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 6 7.1. Normative References . . . . . . . . . . . . . . . . . . 6 7.2. Informative References . . . . . . . . . . . . . . . . . 7 Appendix A. Questionnaire . . . . . . . . . . . . . . . . . . . 7 A.1. Questionnaire for Vendors or Host Implementors . . . . . 7 A.1.1. Implementation Status . . . . . . . . . . . . . . . . 7 A.1.2. Implementation Specifics . . . . . . . . . . . . . . 7 A.1.3. Implementation Perspectives . . . . . . . . . . . . . 8 A.2. Questionnaire for Network Operators . . . . . . . . . . . 8 A.2.1. Deployment Status . . . . . . . . . . . . . . . . . . 8 A.2.2. Deployment Specifics . . . . . . . . . . . . . . . . 9 A.2.3. Deployment Perspectives . . . . . . . . . . . . . . . 10 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 10 1. Introduction Internet Group Management Protocol Version 3 (IGMPv3) [RFC3376] and Multicast Listener Discovery Version 2 (MLDv2) for IPv6 [RFC3810] are currently Proposed Standards. Given the fact that multiple independent implementations of these protocols exist and they have been successfully and widely used operationally, the PIM WG is keen to progress these protocols to Internet Standards. As such, it is Komolafe Expires March 19, 2021 [Page 2] Internet-Draft IGMPv3 and MLDv2 Survey Report September 2020 critical to establish if there are features specified in [RFC3376] and [RFC3810] that have not been widely used and also to determine any interoperability issues that have arisen from using the protocols. Following approach taken for PIM-SM, documented in [RFC7063], the PIM WG has decided that conducting a comprehensive survey on implementations and deployment of IGMPv3 and MLDv2 will provide valuable information to facilitate their progression to Internet Standard. This document summarizes the findings of the survey. 2. Approach 2.1. Methodology The raw survey questions are shown in Appendix A. In order to make the submission and processing of responses as convenient as possible, Tim Chown kindly formatted and posted the survey online using the JISC online surveys tool. The PIM WG chairs subsequently announced the survey, publicizing the URL at which the survey could be completed. In addition to announcing the survey on the relevant IETF WG mailing lists, effort was made to distribute the survey to other forums such as NANOG. The survey was targeted at: Network operators Router vendors Switch vendors Host implementors Once the deadline for the survey elapsed, Tim Chown collated the responses, anonymizing the data so the responses from a specific operator, vendor or implementor could not be identified. The questions targeted at vendors or host implementors were answered by 10 respondents. The network operators questions were answered by 14 respondents. (These numbers are comparable with the number of responses to the PIM-SM survey [RFC7063].) Komolafe Expires March 19, 2021 [Page 3] Internet-Draft IGMPv3 and MLDv2 Survey Report September 2020 3. Responses for Vendors or Host Implementors 3.1. Protocols Implemented 80% or more of the respondents had implemented each of IGMPv1, IGMPv2, IGMPv3, MLDv1 and MLDv2, with IGMPv3 being the only protocol that had been implemented by all the respondents. In contrast, Lightweight IGMPv3 and Lightweight MLDv2 had been implemented by only 20% of the respondents. 3.2. Features Supported All the respondents supported source filtering with include list. Snooping querier was also a popular feature, with 80% of respondents supporting it. Source filtering with exclude list, snooping proxy, snooping filtering, L2 report flooding, host proxy were moderately popular, with 40%-70% of respondents supporting each of these features. Unicast queries/reports were supported by only 20% of the respondents. 3.3. Issues Identified No ambiguities or inconsistencies in [RFC3376] and [RFC3810] that made the implementation challenging were identified by any respondent. 3.4. Suggestions A number of respondents made suggestions to the PIM WG regarding progressing IGMPv3 and MLDv2 to full standards: o Add source discovery mechanism to SSM in addition to existing application-based source discovery o Improve scalability of query/response messages o Deprecate older versions and streamline IGMPv3 o Allow reports to be sent without a querier o Remove source filtering with exclude list as it is not widely used and makes state machine unnecessarily complicated Each of these points was raised by a different respondent, apart from the last point which was raised by two separate respondents. Komolafe Expires March 19, 2021 [Page 4] Internet-Draft IGMPv3 and MLDv2 Survey Report September 2020 4. Responses for Network Operators 4.1. Protocols Deployed IGMPv2 was the most widely deployed protocol, with 86% of respondents indicating it is running in their network. Next was IGMPv3 with 79% of respondents indicating it is deployed. However only between 20% and 36% of respondents indicated they had deployed IGMPv1, MLDv1 and MLDv2. Lightweight IGMPv3 and Lightweight MLDv2 were undeployed. 4.2. Features Enabled Between 20% and 30% of respondents indicated that had enabled Source filtering with include list, source filtering with exclude list, snooping querier, snooping filtering or unicast queries/reports. Snooping proxy and L2 report flooding were enabled by 7% of respondents. No respondent was using host proxy. 4.3. Interoperability Issues Half the respondents indicated they were using equipment with multi- vendor implementations in their network. No interoperability issues were identified. 4.4. Fallback Mechanism 36% of respondents indicated there are dependent on the fallback mechanisms between the different protocol versions. 7% of respondents have experienced issues related to this fallback mechanism. 4.5. Strengths and Weaknesses of IGMPv3 and MLDv2 A respondent indicated that a significant strength of IGMPv3 was the simplicity introduced by using SSM, avoiding the complexities associated with ASM. The weaknesses associated with IGMPv3 which were identified were: o No CPE implementations o Automatic fallback makes deployments challenging o ASM provides better source filtering (by potentially restricting the acceptance of register messages at the RP) whereas SSM allows only data plane filtering using multicast boundary Komolafe Expires March 19, 2021 [Page 5] Internet-Draft IGMPv3 and MLDv2 Survey Report September 2020 5. Conclusions There were a total of 24 respondents to the survey which asked vendors/implementors and network operators questions about IGMPv1, IGMPv2, IGMPv3, Lightweight IGMPv3, MLDv1, MLDv2 and Lightweight MLDv2. A reasonable number of responses were gathered to the survey, allowing some interesting observations to be made. Firstly, and perhaps unsurprisingly, operators use a lower number of protocols and protocol features than have been implemented. Furthermore, there is a relatively much lower deployment of the different MLD versions, indicating that IPv6 multicast is not widely used. No major flaws, inconsistencies or ambiguity in the IGMPv3 [RFC3376] and MLDv2 [RFC3810] specifications were identified. However, a number of concerns were raised about the usage of these protocols, notably concerns about the automatic fallback from IGMPv3 to IGMPv2 being sometimes problematic and the loss of certain features offered by the ASM control plane being lost with the transition to SSM. These findings suggest that IGMPv3 and MLDv2 are indeed ready for progression to Internet Standards. 6. Acknowledgements The authors are grateful to Tim Chown for posting the survey online, and for collating and anonymizing the responses. 7. References 7.1. Normative References [RFC1112] Deering, S., "Host Extensions for IP Multicasting", RFC 1112, August 1989. [RFC2236] Fenner, W., "Internet Group Management Protocol, Version 2", RFC 2236, November 1997. [RFC3376] Cain, B., Deering, S., Kouvelas, I., Fenner, B., and A. Thyagarajan, "Internet Group Management Protocol, Version 3", RFC 3376, October 2002. [RFC2710] Deering, S., Fenner, W., and B. Haberman, "Multicast Listener Discovery (MLD) for IPv6", RFC 2710, October 1999. [RFC3810] Vida, R. and L. Costa, "Multicast Listener Discovery Version 2 (MLDv2) for IPv6", RFC 3810, June 2004. Komolafe Expires March 19, 2021 [Page 6] Internet-Draft IGMPv3 and MLDv2 Survey Report September 2020 [RFC5790] Liu, H., Cao, W., and H. Asaeda, "Lightweight Internet Group Management Protocol Version 3 (IGMPv3) and Multicast Listener Discovery Version 2 (MLDv2) Protocols", RFC 5790, February 2010. 7.2. Informative References [RFC7063] Zheng, L., Zhang, Z., and R. Parekh, "Survey Report on Protocol Independent Multicast - Sparse Mode (PIM-SM) Implementations and Deployments", RFC 7063, December 2013. Appendix A. Questionnaire A.1. Questionnaire for Vendors or Host Implementors Name: Affiliation/Organization: Contact Email: Do you wish to complete the survey anonymously?: Y/N A.1.1. Implementation Status Which of the following have you implemented? 1. IGMPv1 [RFC1112]? 2. IGMPv2 [RFC2236]? 3. IGMPv3 [RFC3376]? 4. Lightweight IGMPv3 [RFC5790]? 5. MLDv1 [RFC2710]? 6. MLDv2 [RFC3810]? 7. Lightweight MLDv2 [RFC5790]? A.1.2. Implementation Specifics 1. Which IGMPv3 and MLDv2 features have you implemented? A. Source filtering with include list? B. Source filtering with exclude list? Komolafe Expires March 19, 2021 [Page 7] Internet-Draft IGMPv3 and MLDv2 Survey Report September 2020 C. Snooping proxy? D. Snooping querier? E. Snooping filtering? F. L2 Report flooding? G. Host proxy? H. Unicast queries/reports? 2. Have you carried out IGMPv3 or MLDv2 interoperability tests with other implementations? A. What issues, if any, arose during these tests? B. How could [RFC3376] and [RFC3810] have helped minimize these issues? A.1.3. Implementation Perspectives 1. Which ambiguities or inconsistencies in RFC 3376 or RFC 3810 made the implementation challenging? 2. What suggestions would you make to the PIM WG as it seeks to progress IGMPv3 and MLDv2 to Internet Standard? A.2. Questionnaire for Network Operators Name: Affiliation/Organization: Contact Email: Do you wish to complete the survey anonymously?: Y/N: A.2.1. Deployment Status Which of the following have you deployed in your network? 1. IGMPv1 [RFC1112]? 2. IGMPv2 [RFC2236]? 3. IGMPv3 [RFC3376]? Komolafe Expires March 19, 2021 [Page 8] Internet-Draft IGMPv3 and MLDv2 Survey Report September 2020 4. Lightweight IGMPv3 [RFC5790]? 5. MLDv1 [RFC2710]? 6. MLDv2 [RFC3810]? 7. Lightweight MLDv2 [RFC5790]? A.2.2. Deployment Specifics 1. Which IGMPv3 and MLDv2 features do you use? A. Source filtering with include list? B. Source filtering with exclude list? C. Snooping proxy? D. Snooping querier? E. Snooping filtering? F. L2 Report flooding? G. Host proxy? H. Unicast queries/reports? 2. Are you using equipment with multi-vendor implementations in your IGMPv3/MLDv2 deployment? A. What inter-operability issues, if any, have you experienced? B. How could [RFC3376] and [RFC3810] have helped minimize these issues? 3. Are you using different IGMP versions or different MLD versions in your network? A. Are you dependent on the fallback mechanism between the different versions? B. Have you experienced any issues related to the fallback mechanism between the different versions? C. How could [RFC3376] and [RFC3810] have helped minimize these issues? Komolafe Expires March 19, 2021 [Page 9] Internet-Draft IGMPv3 and MLDv2 Survey Report September 2020 A.2.3. Deployment Perspectives 1. Based on your operational experience, What have you found to be the strengths of IGMPv3 or MLDv2? 2. What have you found to be the weaknesses of IGMPv3 or MLDv2? 3. What suggestions would you make to the PIM WG as it seeks to progress IGMPv3 and MLDv2 to Internet Standard? Author's Address Olufemi Komolafe Arista Networks Email: femi@arista.com Komolafe Expires March 19, 2021 [Page 10]