Internet DRAFT - draft-komolafe-pim-igmp-mld-survey-report
draft-komolafe-pim-igmp-mld-survey-report
PIM Working Group O. Komolafe
Internet-Draft Arista Networks
Intended status: Informational September 29, 2020
Expires: April 2, 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
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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
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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].)
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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.
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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, between only 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
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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 lower deployment of the different MLD versions,
suggesting that IPv6 multicast is less widely used than IPv4
multicast. No major flaws, inconsistencies or ambiguity in the
IGMPv3 [RFC3376] and MLDv2 [RFC3810] specifications were identified.
However, a number of issues 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 useful
features offered by the ASM control plane 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.
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[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?
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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]?
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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?
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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
UK
Email: femi@arista.com
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