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Philips Research

The role of IP for Interactive Services and In-Home

Networks

Architectural Choices

Winfried Berkvens

Philips Research Eindhoven

Philips Research

Overview

• Addressing of devices in the home• Heterogeneous in-home networks• Supporting multiple ISPs on a cable-

network• Summary

Philips Research

Overview

• Addressing of devices in the home• Heterogeneous in-home networks• Supporting multiple ISPs on a cable-

network• Summary

Philips Research

Choosing Address Domains (1)

• Create one IP address domain for AN and IHN; addressing functionality provided by Access Service Provider (ASP)

RG IHNAN

AN + IHN address domain

Philips Research

Choosing Address Domains (2)

• Create separate IP address domains for AN and IHN; addressing functionality for home devices located in IHN

RG IHN

IHDN address domainAN address domain

AN

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One Address Domain (1)

• Each home device needs to communicate with ASP every time it likes to obtain an IP address

• More difficult to secure the IHN• ASP has to assure that home devices

within one home can communicate with each other

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One Address Domain (2)

• Addressing functionality in ASP becomes almost unmanageable due to the required intelligent distribution of IP addresses– Sufficient IP addresses (forming one

subnet) have to be reserved for each IHN

– Scalability of this approach is questionable

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Separate Address Domains (1)

• Securing of the complete IHN is simplified– Only one point of access (RG)

• No communication required to the AN for IP address assignment to a home device– Problems if this network is not available

– RG does not need to be always connected

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Separate Address Domains (2)

• Expanding of the IHN becomes easier• Direct communication between all in-

home IP capable devices possible• Management of the networks becomes

easier, however IHN cannot be managed from outside

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IP Functionality required when using Separate Address Domains

RGAN IHN

DHCP, NA(P)T,DNS, DNS_ALG

IHN address domainAN address domain

Philips Research

Overview

• Addressing of devices in the home• Heterogeneous in-home networks• Supporting multiple ISPs on a cable-

network• Summary

Philips Research

Heterogeneous IHNs

• Multi-network environment– interconnected via the RG

– interconnected via an Inter-Network Device

RG

IHN1

AN

IHN3

IHN2IND

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Separate Address Domain for each IHN (1)

• Duplication of IP functionality inside the home network

• NA(P)T functionality in IND becomes more complex if the same private address range is used by several networks

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Separate Address Domain for each IHN (2)

• Moving a device between IHNs requires– New IP address for the device (difficult to

find device again)

– Updating of DNS-tables

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One IHN Address Domain

• Addressing functionality located in one device (the RG), no unnecessary duplication of functionality

• Enables direct communication between all home devices (Intranet)– All IP addresses from one address range

– If subnetting is used (devices moving between subnets require new address)

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IP Functionality required when using one IHN Address Domain

• IP addresses in one range (no subnets)

RG

IHN1

AN

IHN3

IHN2IND

Proxy ARP

Proxy ARP

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IP Functionality required when using one IHN Address Domain

• If subnets are used

RG

IHN1

AN

IHN3

IHN2IND

IP-routerBOOTP relay agent

InternalIP-router

Philips Research

Overview

• Addressing of devices in the home• Heterogeneous in-home networks• Supporting multiple ISPs on a cable-

network• Summary

Philips Research

Cable-Network Architecture Supporting Multiple ISP’s

ASP INA ANIntranetof ASP

RG

ISP_1

Internet

ISP_nDHCP ASP: owner of the

Access NetworkISP: provides the(Internet) service

NA(P)T

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Required Functionality for Multiple ISP Architecture

• The ASP provides IP addresses for all RGs and the connected ISPs. So, RGs can communicate directly with the ISPs

• The ISPs should provide the NA(P)T functionality if connections to the Internet are required

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Summary (1)

• Separate address domain AN and IHN• DHCP, NA(P)T, DNS, DNS_ALG

• One address range in the home– No subnets

• Proxy ARP in RG and IND

– Subnets• IP-router, BOOTP relay agent

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Summary (2)

• One address space per AN• DHCP (in ASP)

• NA(P)T (in ISP)

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Other Issues

• Wireless devices entering and leaving the home network

• Mobile devices able to connect to their home network when away

• Multiple RGs or connections to various access networks

• QoS guarantees for requested services

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