Post on 20-Jun-2020
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
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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
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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
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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
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• 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
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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
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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
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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
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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
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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
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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
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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)
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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
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Backups
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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
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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.
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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
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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
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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
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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