Krishan Sabnani Bell Labs. Converged Networks of the Future

Transcription

1 Krishan Sabnani Bell Labs Converged Networks of the Future

2 Today s Networks 3G Cellular Networks Radio Controller Aggregation Access Enterprise Networks Metro Networks Access Packet-Based Network Aggregation Access Ad hoc Networks Aggregation Home Networks 2

3 Tomorrow s Converged Network Integrated Network Management Security Reliability 3G Cellular Networks Next-Gen Metro Networks Radio Controller Access Global Roaming Edge Always-On QoS-Enabled Packet Core Network Access Enterprise Networks Quality of Service (e.g. for voice) Services Enablement Layer User Mobility Edge Personalization Network Intelligence Edge Home Networks 4G/Mesh Access Traffic Type (Multimedia) 3

4 Tomorrow s Converged Network: Technical Challenges Access: Core: 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 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 4

5 Enabling Technologies Access: Provide homogeneous bit stream to the Internet Base Station Core: Enable carrier grade performance and features Soft Applications: Consistent services should be accessible regardless of location Always-on Services 5

6 New Cellular Network Architecture Base Station : push intelligence to the edge Current wireless networks are complex, involving many network elements, and result in high cost and high latency Base Station terminates all air interface-specific functionality in the base station Base Station ATM IP O Radio Controller circuit voice O Mobile Switching Center Telephone Network Base Station ATM IP O Serving GPRS Service Node packet data O Gateway GPRS Service Node Internet Collapsing Radio Access Network elements into the base station simplifies network and reduces latency Base Station Pushing IP intelligence to the base station results in better Quality of Service support 6

7 Enabling Technologies Access: Provide homogeneous bit stream to the Internet Base Station Core: Enable carrier grade performance and features Soft Applications: Consistent services should be accessible regardless of location Always-on Services 7

8 New Architecture: Soft 3 key components of Soft 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 Proprietary Control Plane API Control plane processing Forwarding plane processing Control Element Server Packet Forwarding Element Feature Server Standard protocol Transport Plane Current Model Soft Model 8

9 Soft Benefits 1. 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 9

10 Scaling Mobile IP using Soft Mobile Switching Center CDMA Base Station RAN Home Agent Forwarding Elements Home Agent Signaling on Control Element Server PSTN Internet Mobile IP Home Agent will require increasing scalability as cellular carriers introduce wireless data Two approaches to Mobile IP implementation today s: 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 10

11 Enabling Technologies Access: Provide homogeneous bit stream to the Internet Base Station Core: Enable carrier grade performance and features Soft Applications: Consistent services should be accessible regardless of location Always-on Services 11

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 12

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 Current Network PTT server complex Always On Gateway (AOG) Always On Redirector (AOR) Proposed Network Overlay AOG AOR 3G Push to Talk 3G Centralized Single wireless technology (3G) Single carrier Single Application Push to Talk Push to View 3G Internet 802.1x Distributed Multiple wireless technology (3G,802.1x) Multiple carriers Multiple Applications (Push to View, Push to Game) 13

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 collapses wireless specific features into a single box and provides a homogeneous interface to the core Soft 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 14

15 Backups 15

16 Soft Network Architecture Control Element Server Traditional -based Network Packet Forwarding Element Feature Server Soft-based Network Soft separates and centralizes the software-based route controller (Soft) from hardware-based transport and packet forwarding 16

17 How does Always On work? Without Always On 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 Air-interface related Select and Acquire Channel Device-related Authenticate Device Register Device Network-related Set up Link level connection Allocate IP address Application-related Authenticate client Set up Connection Respond to client req Several minutes Client 3G Network Server With Always-On Application-related Wake Application from sleep Connect to service Access service A Few Seconds Air-interface related Select and Acquire Channel Network-related Maintain Persistent session Application-related Maintain Persistent Session Respond to client req A class of always-on applications is Push-to-Connect that instantly connects a user to a service. 17

18 Working Principle of Current Services User 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 Server Authenticates user Executes service protocols with user Queries network for user s location, presence Delivers content to user User 3G Network Location Server Application Servers Content delivery & application execution at network edge 18

19 Key Problems with Current Services Issues Delay Complexity Scalability Large network distance between user and service Complex message exchange between user and server for setup, control and content Manual user authentication for each service subscribed to Huge amount of service state regenerated during each session setup Periodic queries for users location and presence for location/presence-based services Large number of end-to-end sessions between users and services Wasted network resources due to redundant distribution of content 19

20 The Soft Disaggregation Approach Soft approach is based on disaggregation of router hardware from router software using openstandards-based protocols for interworking 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 20

21 Addressing the Problems Solution: Add Add service intelligence to to an an existing network 1. Bring service closer to user Incorporate service logic into the network (traditionally done at network edge) User 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 3G Network AoG AoG AoG Content delivery and application execution within network Application Servers Content and application distribution overlay network 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 21

22 Scaling Mobile IP using Soft Mobile Switching Center CDMA PSTN HLR AAA Base Station Base Station Controller PDSN/IGSN Mobile IP Signaling on server Mobile IP Home Agent will require increasing scalability as cellular carriers introduce wireless data Two approaches to Mobile IP implementation today s: 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 a Home Agent Internet 22