Data Over Cable and the @Home Network

Stan Barber's Notes

About @HOME

Silicon Valley Startup
Formed by TCI and Kleiner-Perkins
Partners with multiple Cable MSO's

Service Goal

Deliever scaleable high performance network services over broadband cable to millions of homes.

Cable is Unique

Widely deployed to millions of homes
Currently the highest bandwidth of any pervasive infrastruture
Cable is not connection oriented -- the network can be connected all the time
This supports a flat-rate pricing modern more naturally than current telco.
Modern Hybrid Fiber-Coax (HFC) infrastructure and can support very cost effective multi-service delivery

Infrastucture

Headend <--> FM over fiber <--> Fiber to Electrical conversion <--> coax to the home

Cable has the incentive

DBS is a better way of delivering one-way video.
No existing data services to cannibalize.
Have local field force in the community.
Data transport is a relativity low-cost add-on to modem HFC infrastructure.
Data services can help provide better support for other serivces.

@Home service to consumer

Cable modem delivers data from the RF plant
10Mbps Ethernet (10-Base-T) as the interface providing IP dialtone
Home LAN's supported
Software to make it all work on multiple platforms (NetScape is involved)

Information Services

@Home is not a content provider, but works with them.
@Home works non-exclusively with content partners to advance broadband content
Must push local content in order to be relevant to most consumers
@Home will provide directory servicess
Also, the usual services: News/mail, etc

Architectural Issues

How to proactively manage reliable network communications to the User?

@Home Core Assertions

Cannot scale the system just by adding communications capacity
Network must cache and replicate content to provide support "fanout"
Multicasting in the proper model for many services, not HTTP
Computing responsibilities must be distributed even to the client (e.g. Java)
Must control topology to scale
KISS wins

Architecture

ATM Services Backbone connected to various NAPS
[ATM is available and fast, not bright.]
Regional Networks serving a number of cable operators
Headends at the various cable operators
Home (768 Kbps from the home, 27 megabits/second to the home)

Subscriber Installation

CATV Line -- > Splitter --> TV
                 --> Cable Modem -- > PC (maybe wireless)

Caching Service Benefits

Provides superios service to users since data is coming from a local server
Greatly reduces network load up from the head end system (e.g. the broader Internet
Provides much greater network management information
Can potentially help implement parental control filtering

Replicating Service

Mirrors data from content providers in every or serveral regions
Reduces load on Backbone and "Internet"
Can execute scripts on @Home serviers through JavaScript capabilities
Can bill through @Home backoffice for services or content
Also provides email, News, etc...service

Multicasting

Systems supports multicasting end-to-end using standard Internet protocols
Greatly eases scaling issues for dynamic content, especially when coupled with Java in browser
Network supports "cloning" of data with different scopes
Will be one-way multicast initially with 2-way support when modems have better controls

Priortization

@Home infrastructure support priority queuing of traffic
Perimeter routers set IP precedence
Internal servers can set precedence

Cable Modems

Currently immature technology
Will be manufactured in large volume starting in 1996
Many large manufacturers are getting into this business
No real standards for interoperability
New consortiums being formed to drive standards

First Award

Motorola awared first contract from TCI for cable modems
200,000 modems to TCI in 1996 with additional MSO's piggybacking
27Mbps down, 768 Kbps up after FEC
Software downloadable, and network savvy
HFC patch encrypted

Tentative Schedule

Deploy in Sunnyvale Ca in 2Q96
Aggresively deply though 1996 on a national and possibly international basis
Pricing targeting at $30-$40/month, flat-rate
@Work and @School businesses, too.

Questions

Can you send ip from @Home to other places on the Internet? Yes, but it may not be as fast as using @Home services. An on-line service is perceived as performing better than the Internet.

How will address assignment handled? DHCP will be used, but static addressing will be done. DHCP is used to make renumbering easy, not to share addressing. CIDR addressing will be used inside as well as outside the network.

How will content providers get stats on the information that is used?

Expires field can be used.
Other Methods

What about putting a server at home? This will be cost driven. The modem systems will arbitrate access such that no one will be able get all bandwidth at a time.

Can the corporate culture of the cable industry be modified such that the critically of the data is realized? Some people in the cable company think they can deliver dramatically better service.

In locations where the hybrid cable system is not available, will @Home work? Yes, if the number of subscribers is small. At the end of this year, over 35% of the cable plants will be adapted to HFC.

How will folks on @Home be able to access corporate network? It is really up the the companies to do this. @Home will be transparent to this as any other IP provider is. Alternatively, corporation can get direct connections to @Home.

Will @Home support Internet Phone? @Home is not going to prohibit the use of Internet Phone, but is not going to institutionalize it at this time.

What IP address space will be used by @Home? @Home is using Net 24 for its allocation.