IETF 63 - Paris
VOIPPEER BoF
A Broadband Service
Provider’s Perspective
on VoIP Peering
August 5, 2005
Presented by Jason Livingood
The Context for VoIP Peering
• If it originates on IP and terminates on IP, why convert it to
something else in the middle?
– Adds cost and complexity (operational & network).
– Decreases control over:
• User Experience
• Services & Quality
• Network / Troubleshooting
• So… Keep communications IP-based, end-to-end.
• IP networks are generally private & free of traditional telecom
regulation.
• Helps make possible new, broadband IP-based services, not
possible via PSTN.
• Many big economic and strategic motivations…
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The Context for ENUM in VoIP Peering
• Without ENUM:
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Each switch (CMS) is largely an island unto itself.
Linking many CMSs is difficult to scale.
Vendor-specific methods to share TN / IP data.
Legacy / PSTN-centric solutions (inefficient via IP).
• ENUM can tell me, for a dialed TN, what IP network element
(CMS, Proxy, SBC, etc.) to send a call to.
• Can help to enable easily scalable:
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CMS-to-CMS calling (all PacketCable).
PacketCable-to-SIP calling.
Fixed-to-wireless calling.
MSO-to-MSO calling.
MSO-to-any IP-based carrier calling.
• BUT, ENUM is just one part of the solution (lest we forget SIP).
• Laying the foundation now: (1) Working to use ENUM as part of a
solution to simplify call routing; peering work is incremental.
(2) Working on backbone for peering and other uses (takes time).
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Preparing a Backbone for Intra/Inter-Network Peering
National Backbone Network
Features
• Links all the regional networks into a unified
network.
• Consolidates peering and interconnection
with other operators.
• Managed QoS delivery end-to-end with no
third-parties involved.
• Supports centralized management functions.
Benefits
Comcast
territory
• Over 19,000 route miles of national fiber
• Covers 95+% of Homes Passed
• All major peering points
• Transport capability of >2500+ Gbps in 2005
• 40Gbps IP links in 2005
•QoS based voice, video and data over IP
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• Very flexible and low cost linear and
OnDemand video distribution.
• Backbone transport payments to transit
providers reduced.
• Reduce overall operational costs and
complexity by supporting centralization.
• Increased revenue opportunities by providing
high quality, national end-to-end services.
Private ENUM & VoIP Peering
• Development work underway with CableLabs (more later).
• Could prioritize peering priorities based on economics
(similar to peering analysis used in HSI peering) and/or
business strategy.
• Comcast and other parties could begin using private ENUM
to peer without waiting for public “1.e164.arpa” being up
and running. (Short-term hedge.)
• Communications peering over IP could enable the
federation of multimedia services not feasible over the
PSTN due to bandwidth constraints.
– Leverages unique capabilities of broadband networks.
– Could include both TN-addressed and URI-addressed communications.
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Public ENUM & VoIP Peering
• Bi-Lateral / multi-lateral, private trees will only scale so
far before operational and management challenges
present themselves.
• Thus, Public ENUM is a long-term goal.
– What form will this take? (Carrier or User ENUM)
• Without carriers in e164.arpa is the business model for “User”
sustainable?
– Will there be a mix of different peering types?
• Private POPs, with committed capacity.
• Public peering points.
• Over the Internet generally, best effort (no QoS).
• Bottom line: Working towards public ENUM in the future
(very important), while hedging our bets with work on
private ENUM in the shorter term.
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Specific Near-Term VoIP Peering Challenges
• Provisioning into / security for ENUM tree.
• Normalization of different SIP profiles between providers.
• Trust at network edge.
• Security / encryption at network edge.
• QoS at network edge / passing QoS between parties.
• Lawful intercept.
• Selection of best IP routes & advertising routes as # POPs increases.
• Failover to PSTN routes in the event of IP route failure.
• Explore the role of SBCs.
• Some PacketCable™-related work on interfaces needed.
– Evolves into part of PacketCable 2.0.
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PacketCable™ 2.0 Standards Development
• Driven to support:
– Backward-Compatible (PacketCable Multimedia & PC 1.X)
– Enhanced Telephony
– Video Telephony
– Cross-Platform (voice/video/data convergence) Features
– Cellular Integration
– Presence and Availability
– ENUM / Peering
– Commercial Service Extensions
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In Summary
• What VoIP Peering Is About for Us:
– It is about a lot more than saving money.
– It is more than just “voice” communications.
– It is about enabling new services not possible on the PSTN.
– It is about creating / increasing network effects; supercharging adoption.
– It is about end-to-end control over communications and staying all-IP.
– It is about reducing complexity & increasing efficiency vs. “PSTN-imitation”
models. (“Keeping IP in VoIP”)
• VoIP Peering is important to companies like Comcast.
• Building network and systems infrastructure now.
• Both ENUM and SIP are important to this effort; basic standards /
protocol groundwork is there.
• Some incremental standards work is necessary and vital to success.
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Thank You!
Questions?
Jason Livingood
jason_livingood@cable.comcast.com
+1-215-981-7813
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