W3C Multicast CG @TPAC

2021-10-27, 8am Pacific Time

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Chair: Jake Holland (Akamai)

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Recording?

This meeting will be recorded unless someone objects.

The purpose of recording is to aid with minutes, enable later review of comments, and to help future new or prospective group members get oriented. The video will be posted to Youtube and made publicly available without an expiration.

If requested by recorded participants, sections of the public recording will be redacted to their satisfaction as needed, before or after publication (caveat: after publication there may be copies outside our control).

A link to the recording will be kept in the meeting log here (and updated if replaced with a redacted recording): https://github.com/w3c/multicast-cg/tree/main/meetings

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W3C Policies

• Substantive Contributions can only be made by Community Group Participants who have agreed to the W3C Community Contributor License Agreement (CLA).�
• This meeting operates under W3C Code of Ethics and Professional Conduct�
• We're all passionate about improving Multicast and the Web, but let's all keep the conversations cordial and professional.

Meeting Info

• Agenda & Logistics:�https://github.com/w3c/multicast-cg/blob/main/meetings/minutes/tpac-2021-agenda.md�
• IRC: https://irc.w3.org/?channels=#multicast�
• Scribe?

Agenda

• Welcome, Agenda-bash (~10)
• Intro to Multicast-CG (~15)
• Next Steps & Working Sessions (~25)
• Wrap-up & summary (~5)

Multicast CG

Mission:

to enable multicast IP transport for web traffic to efficiently solve scalability problems in networking and web operations.

https://w3c.github.io/multicast-cg/multicast-cg-charter.html

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Goal: adding a capability to browsers to receive some kind of multicast, while maintaining web security requirements.

(No sending. Not arbitrary traffic.)

Why: User Experience (Effects of Congestion)

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Observed goodput to large ISP by Time of Day (normal-traffic day, 100KB+ objects)

Why: User Experience (Effects of heavy Congestion)

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Observed goodput to same ISP* by Time of Day (high-traffic day, 100KB+ objects)

* NB: effect present in most ISPs, but not always this clear a signal.��By eye: ~½ the goodput for a 9-hour peak

Key Problem Solved: Access Network Congestion

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Cable Network Diagram By Saub09 at English Wikibooks, CC BY-SA 2.5, https://commons.wikimedia.org/w/index.php?curid=61793561

Deepest Useful Caches

Problematic

Congestion

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Broadcast link capabilities can be leveraged by multicast? (up to?)

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• Fiber (GPON, etc): yes (~3k/ONT)
• Cable: yes (~2k/service group)
• DSL: depends (~1.5k/chassis)
• PPP-based deployments can’t use broadcast
• Helps uplink bandwidth, but similar power usage
• Ethernet: usually (~2k in enterprise/university/apartment networks)
• Needs L2 snooping & replication capability--usually there, not always
• 3G & 4G: sort-of (with eMBMS: ~3k/tower, special signaling)
• 5G: yes (with Xcast: ~3k/tower?, normal signaling?)
• ATSC: maybe one day (~10-100k/antenna, will need special signaling)

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(* Wifi in homes may need updates--solutions exist, deployment spotty)

Access Technologies: gain estimates at bottleneck links

• Climate Impact
• Internet=3.7%* of global carbon footprint (2019 estimate)
• 1% is from watching video (300m tonnes)
• 24m tonnes from video games (chiefly downloads?)

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• Cost of delivery & services
• Network capital costs driven by peak load
• Power needs/provider costs scale with traffic volume
• Lower costs + competition => lower price for users

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Other Effects

* “Why your internet habits are not as clean as you think”, 2020-03-05, BBC

Avoidable Traffic (game/os downloads - new releases)

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Under 100 streams: >40% reduction in peak load to ISP (high-traffic day)

Avoidable Traffic (web video)

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1 stream, >15% reduction in peak load to ISP (popular sport event day)

Getting Started

https://github.com/w3c/multicast-cg/blob/main/primers/01-getting-started.md

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Gaps to Address & Docs to Read

• Security Model�https://datatracker.ietf.org/doc/html/draft-krose-multicast-security
• privacy fingerprinting open questions
• (e.g. disable for incognito mode? Is it necessary? Is it enough?)
• shared encryption keys�(as in https://datatracker.ietf.org/doc/html/draft-pardue-quic-http-mcast)
• separation of encryption & authentication functions�(https://datatracker.ietf.org/doc/html/draft-ietf-mboned-ambi)
• Backpressure via stream cutoff (can’t slow sender…)�https://datatracker.ietf.org/doc/html/draft-ietf-mboned-cbacc
• Define Signaling for Target APIs

Next Steps

• QUIC with multicast: key next experiments
• nghq (uses ls-qcast for quic framing, does multicast)
• aioquic (webtransport WPT server’s implementation)
• Pros & Cons discussion?
• Working Session schedule?
• AMBI implementation, once QUIC can do something
• secdispatch comments?
• Hackathon opportunity
• https://lists.geant.org/sympa/arc/multicast-discuss/2021-10/msg00000.html

Wrap-up

• Summary
• Action Items
• Thanks!