Converged Networks of the Future

Krishan SabnaniBell Labs

2

Today’s Networks

AccessRouterAccessRouter

3G CellularNetworks

RadioController

RadioController

AccessRouterAccessRouter

EnterpriseNetworks

HomeNetworks

MetroNetworks Packet-Based

Network

AggregationRouter

AggregationRouter

AggregationRouter

AggregationRouter

AggregationRouter

AggregationRouter

AccessRouterAccessRouter

Ad hocNetworks

3

Integrated Network Management

Tomorrow’s Converged Network

EdgeRouterEdge

Router

AccessRouterAccessRouter

AccessRouterAccessRouter

3G CellularNetworks

RadioController

RadioController

AccessRouterAccessRouter

EnterpriseNetworks

HomeNetworks

Next-GenMetro

Networks

4G/Mesh

UserMobility

Traffic Type(Multimedia)

Qualityof Service

(e.g. for voice)

Network Intelligence

Security Reliability

QoS-EnabledPacket Core Network

EdgeRouterEdge

Router

EdgeRouterEdge

Router

Services Enablement Layer

Always-OnAlways-OnGlobal RoamingGlobal Roaming

PersonalizationPersonalization

4

Tomorrow’s Converged Network: Technical Challenges

• Access:– Today’s cellular wireless access networks comprise of complex Radio Access Networks with wireless functionality distributed amongst multiple boxes– Goal: Provide homogeneous bit stream to the Internet through a single box

• Core:– Today’s IP networks are best-effort, hard to manage and not secure– Goal: Enable carrier grade performance and features

• Applications– Services in today’s networks are inconsistent and vary with access technology or location – Goal: Consistent services should be accessible regardless of location or access mechanism

5

Enabling Technologies

• Access: Provide homogeneous bit stream to the Internet– Base Station Router

• Core: Enable carrier grade performance and features– SoftRouter

• Applications: Consistent services should be accessible regardless of location– Always-on Services

6

• Current wireless networks are complex, involving many networkelements, and result in high cost and high latency

• Base Station Router terminates all air interface-specific functionality in the base station

New Cellular Network ArchitectureBase Station Router: push intelligence to the edge

Collapsing Radio Access Network elements into the base station simplifies network and reduces latency

Pushing IP intelligence to the base station results in better Quality of Service support

Base Station

O

MobileSwitching

CenterBase

Station

O

Serving GPRS

Service Node

O

RadioController

ATMIP

ATMIP

Telephone Network

Internetpacketdata

circuitvoice

Base Station Router

O

Gateway GPRS

Service Node

7

Enabling Technologies

• Access: Provide homogeneous bit stream to the Internet– Base Station Router

• Core: Enable carrier grade performance and features– SoftRouter

• Applications: Consistent services should be accessible regardless of location– Always-on Services

8

New Router Architecture: SoftRouter

3 key components of SoftRouter approach– Decoupling: Separate complex control plane processing functions

from the transport plane– Servers: Implement control plane processing functions on dedicated

external control plane servers– Standard Interface: Define standard protocol for control plane servers

to interface to the forwarding elements

Control plane

processing

Forwarding plane

processing

ProprietaryAPI

Standardprotocol

Current Router Model SoftRouter Model

Control Plane

Transport Plane

FeatureServer

PacketForwardingElement

Control ElementServer

9

SoftRouter Benefits1. Lower Costs

– Commoditized, standards-based hardware (lower capex)– Dedicated control plane servers imply fewer management points (lower opex)

2. New Applications

– Network-based applications to support new services more easily added using open APIs

– Incremental deployment made simpler through centralized management

3. Better Scalability

– Centralized control plane servers easier to scale using well-established server scaling techniques

4. Enhanced Reliability

– Forwarding elements more robust due to reduced software

5. Increased Security

– Fewer control plane servers easier to secure using perimeter defense systems, e.g., firewalls

10

Scaling Mobile IP using SoftRouter

• Mobile IP Home Agent will require increasing scalability as cellular carriers introduce wireless data

• Two approaches to Mobile IP implementation today– Routers: Current routers support 200K+ home agents for forwarding but signaling

limited to less than 2 updates per hour per user– Servers: Server-based Mobile IP implementation in Cluster processors allows

high signaling update processing but scaling the number of home agents for forwarding is an issue since IPSec processing is CPU intensive

• Disaggregated model allows server based signaling scalability while retaining hardware based transport scalability

– Transport still handled by FEs with hardware support for IPsec– Signaling capacity can easily be scaled using multiple blade servers, thus

enabling 60 updates/hour/mobile user or more

Home Agent Signaling onControl Element Server

CDMA

Internet

PSTN

Base Station

Mobile Switching Center

Home AgentForwarding Elements

RAN

11

Enabling Technologies

• Access: Provide homogeneous bit stream to the Internet– Base Station Router

• Core: Enable carrier grade performance and features– SoftRouter

• Applications: Consistent services should be accessible regardless of location– Always-on Services

12

Always-On Services

• Definition: A push-to-connect data service is “always-on” if it:– Connects the user to the service instantly– Delivers service content to the user instantly– Is easy for a user to use (requires few button presses on a handset)

• To achieve this effectively, the network must:– Provide a persistent session between mobile users and services – Minimize delay in connecting to and controlling a service– Minimize delay in delivering service content– Handle complex interactions on behalf of the user– Scale to a large number of services and subscribers– Support easy deployment of new services

Our objective: Build overlay networking infrastructure that achieves the above goals

13

Approach• Build a common access-agnostic overlay network for supporting

PTC services.– Provides common infrastructure for “generic” PTC applications– Enables PTC applications across carriers– Enables PTC applications across heterogeneous wireless networks– Improves scalability

3G 802.1xInternet

Overlay

AOG

AOR

3G 3G

PTT server complex

Centralized Single wireless technology (3G)Single carrierSingle Application

Distributed Multiple wireless technology (3G,802.1x)Multiple carriersMultiple Applications (Push to View, Push to Game)

Current Network Proposed NetworkAlways On Gateway(AOG)

Push to TalkPush to TalkPush to View

Always On Redirector(AOR)

14

Conclusions

• Next-generation converged networks promise: “The world in your hands”.

• Technical challenges in three key areas must be overcome to realize the promise of network convergence– Access: Provide homogeneous bit stream to the Internet– Core: Enable carrier grade performance and features– Applications: Consistent services accessible regardless of

location• Exciting Progress is being made to address these challenges

– Base Station Router collapses wireless specific features into a single box and provides a homogeneous interface to the core

– SoftRouter architecture disaggregates the IP transport and control plane and enables easy addition of carrier grade services

– Application Enablers such as Always-on provide a uniform experience across different services

15

Backups

16

SoftRouter Network Architecture

Router

PacketForwarding

Element

ControlElementServer

Traditional Router-based Network

SoftRouter-basedNetwork

SoftRouter separates and centralizes the software-based route controller (SoftRouter) from hardware-based transport and packet forwarding

FeatureServer

17

How does Always On work?W

ithou

t Alw

ays O

nW

ith A

lway

s-O

n

•Application-related •Authenticate client•Set up Connection •Respond to client req

•Air-interface related•Select and Acquire Channel

•Device-related•Authenticate Device •Register Device

•Network-related•Set up Link level connection •Allocate IP address

• Air-interface related•Select and Acquire Channel

• Network-related•Maintain Persistent session

• Application-related•Maintain Persistent Session•Respond to client req

Client 3G Network Server

• Device-related•Power up device•Boot up Operating System

• Network-related• Set up Connection •Authenticate user

• Application-related•Start Application •Connect to service•Authenticate server •Access service

• Application-related•Wake Application from sleep•Connect to service•Access service

Several minutes

A Few Seconds

A class of always-on applications is Push-to-Connect that instantly connects a user to a service.

18

Working Principle of Current Services

UserUser• Sets up a session with server (for each service)• Authenticates with server (for each service)• Uses complex interaction to communicate with server• Receives content from distant server

Application ServerApplication Server• Authenticates user• Executes service protocols with user• Queries network for user’s location, presence• Delivers content to user

3G Network Application ServersUser

Content delivery & application execution at network edge

Location Server

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Key Problems with Current Services

Periodic queries for users’ location and presence for location/presence-based services

Delay Complexity ScalabilityIssues

Wasted network resources due to redundant distribution of content

Large number of end-to-end sessions between users and services

Huge amount of service state regenerated during each session setup

Manual user authentication for each service subscribed to

Complex message exchange between user and server for setup, control and content

Large network distance between user and service

20

The SoftRouter Disaggregation Approach

• centralizes and allows sharing of complexity– Enables scalable introduction of new functions without unduly

encumbering IP forwarding functions• Encourages software vendors to invest in developing carrier-class

routing software to supply new entrants to the hardware market• Allows each component to focus on its own innovation curve

– Hardware: highest speeds/density at lowest cost– Software: new applications and easier manageability

• Approach similar to SoftSwitch-based disaggregation of class 5 switches into media gateways, call servers, and application servers

SoftRouter approach is based on disaggregation of router hardware from router software using open-standards-based protocols for interworking

21

Addressing the Problems

3G Network Application Servers

AoG

Content delivery and application execution within network

AoG

AoG

User

Content and application distribution overlay network

Solution: Add service intelligence to an existing networkSolution: Add service intelligence to an existing network

1. Bring service closer to user– Incorporate service logic into the network

(traditionally done at network edge)– Cache service content within the network– Impact: service “follows” the user– Reduces delay, improves scalability

2. Bring user closer to service– Maintain key user state in the network– Authenticate user with service– Perform complex protocol processing

on behalf of user– Reduces delay and complexity, enables

simplified interaction between user and service, and saves air-link resources

• Achieve solution by introducing Always-On Gateway (AoG) function– AoG function is either collocated with existing network elements or stand-alone– Set of AoGs effectively forms an overlay network for content and application

distribution– Solution provides an extensible platform for supporting different types of

services

22

Scaling Mobile IP using SoftRouter

• Mobile IP Home Agent will require increasing scalability as cellular carriers introduce wireless data

• Two approaches to Mobile IP implementation today– Routers: Current routers support 200K+ home agents for forwarding but signaling

limited to less than 2 updates per hour per user– Servers: Server-based Mobile IP implementation in Cluster processors allows

high signaling update processing but scaling the number of home agents for forwarding is an issue since IPSec processing is CPU intensive

• Disaggregated model allows server based signaling scalability while retaining hardware based transport scalability

– Transport still handled by FEs with hardware support for IPsec– Signaling capacity can easily be scaled using multiple blade servers, thus

enabling 60 updates/hour/mobile user or more

Mobile IP Signaling on server

a

CDMA HLR

AAA

Internet

PSTN

Base Station

Base StationController

Mobile Switching Center

PDSN/IGSNHome Agent