Post on 22-Dec-2015
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Slides Used In First Retreat
Vision: 100 Mbps to 100 million households
1Gbps to 1 million business
Approach: clean slate, design from first principles
Holistic and inter-disciplinary design Consider the network as a whole
– Access, metro, core regions
– Service and physical transport layers
Consider technology trends for scaling, cost, future-safeness
Archiect with explicit considerations of economic, dependability, security, mult-service
Design with explict goals of enabling tractable analysis and modeling
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What is the 100x100 Project?
Elevator Speech
What is 100x100 project up to?
What is the “meat”?
– What are the key technical challenges?
– What are the key insights and expected contributions?
Is 100x100 project just about speed?
Why 100 Mbps?
– It is too slow, it is too fast
Why cannot IP do 100x100?
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Clean Slate Design
Why is Clean State Design necessary?
Have you established that incremental evolution is impossible?
Is Clean State Design useful?
Any hope of introducing a “revolutionary” solution?
Mainstream views
incremental fixing of Internet is sufficient
radical new solutions have little chance of being deployed
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Context
IP is a great success because its architects set the right goal: global best-effort reachability Global addressing scheme Internetworking architecture Simple best-effort service
Success is a double-edged sword the world demands more from IP and the Internet Convergence telecommunication infrastructure that
provides 7x24x365 service Dependability, scale, security, economic sustainability
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Have We Already Achieved Convergence?
Long HaulMetro CoreSubscriber/
Enterprise
LAN
HAN
Metro Hub Office
End Office/ Collocation
INTERCITYG()
RouterVoice
Switch
ACCESS INTEROFFICEG(SONET)
TransportServices
Metro Access
Router
Service Node/ASPVoice
Switch
Wireless
Server
Server
RF
Cable
Copper
Fiber
ATM
OXC
Voice Switch
Backbone Router
ISP
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UUNet 10/03/02 Outage
as seen from AT&T
IP Robustness?
State of the Art is lacking in robustness on every time scale: days, hours, minutes, seconds
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Molasses
Data Plane Distributed routers forwarding
packets
Based on FIB or labels
OSPFBGP
OSPFBGP
OSPFBGP
Packet filters
Link metrics
Control Plane• Multiple routing processes on each
router• Each router with different
configuration program• Huge number of control knobs:
metrics, ACLs, policy
FIB
FIB
FIB
Configs
Management Plane• Figure out what is happening in
network• Decide how to change it
Shell scripts Tomography
DatabasesPlanning tools
OSPFSNMP rancid modems
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A Study of Operational Production Networks(Joint Between ATT and CMU)
Obtained anonymized configuration files for 31 active networks (>8,000 configuration files)
6 Tier-1 and Tier-2 Internet backbone networks
25 enterprise networks
Sizes between 10 and 1,200 routers
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Packet Filters FIBs
Data Plane ControlPlane
ManagementPlane
Log
ic t
o C
ombi
ne
OS
PF
and
BG
P R
IBs
Hardwired State
Dynamic State
Configuration State
State Dependency
Legends
Complex Interaction of States
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Molasses
Data Plane
Distributed routers forwarding packets
Based on FIB or labels
OSPFBGP
OSPFBGP
OSPFBGP
Packet filters
Link metrics
Control Plane• Multiple routing processes
on each router• Each router with different
configuration program• Huge number of control
knobs: metrics, ACLs, policy
Management Plane• Figure out what is
happening in network• Decide how to change it
Shell scripts Tomography
DatabasesPlanning tools
State everywhere!
• Dynamic state in FIBs
• Configured state in settings, policies, packet filters
• Programmed state in magic constants, timers
• Many dependencies between bits of state
State updated in uncoordinated, decentralized way!
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Systems of Systems
Systems are designed as components to be used in larger systems in different contexts, for different purposes, interacting with different components
Example: OSPF and BGP are complex systems in its own right, they are components in a routing system of a network, interacting with each other and packet filters, interacting with management tools …
Complex configuration to enable flexibility
The glue has tremendous impact on network performance
State of art: multiple interactive distributed programs written in assembly language
Lack of intellectual framework to understand global behavior
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Development of the Elevator Pitch
Best-effort service model is a critical reason for Internet’s success
Success is a double-edged sword
Expectation: with true two-way broadband connectivity to every household (100x100), IP be convergence telecommunication infrastructure that provides 7x24x365 service
Far from being dependable, scaleable, secure, economic sustainable
Even when providing best-effort service, it is already extremely complex
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Observations that Lead to Simplifications
Tremendous focus on protocols/protocol architecture, should also focus on networks and network architecture
Interplay between network architecture and protocol architecture
Architecture agnostic to technology trend Should leverage technology trends that enable simple network architecture
Box/Switch/Router centric distributed control has fundamental limitations, should also explore
Control architecture that can implement a wide range of network-wide
policies
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Protocol Architecture vs. Network Architecture
Protocols: TCP, IP, BGP, OSPF
They work in arbitrary network, but do not work as well in any network
Dependable network requires
– Structured network, and
– protocols that can take advantage of network architecture
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Observation One
Structured network + protocols taking advantage of network structures achieve
Dependable, simple, and understandable network
Dependable, simple, and understandable protocols
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Observations that Lead to Simplifications
Tremendous focus on protocols/protocol architecture, should also focus on networks and network architecture
Interplay between network architecture and protocol architecture
Architecture agnostic to technology trend Should leverage technology trends that enable simple network architecture
Box/Switch/Router centric distributed control has fundamental limitations, should also explore
Control architecture that can implement a wide range of network-wide
policies
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Key Technology Trends
Trend 1: Deep fiber deployment key to achieving ubiquitous, high capacity connectivity to home Wireless: important complementary technology
Copper & cable can also be used for last 1000 feet
Fiber enables not only scalable high speed, but also longer distance
Trend 2: low cost, low energy, high capacity, auto-configured, environmentally hardened access packet switches
Trend 3: ultra high capacity (perabit) backbone switches
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Implications for Network Architecture
Deep fiber + access switch large scale packet access networks
In contrast, traditional access network size limited by copper transmission distance
Large scale access network + ultra high speed backbone switch architecture with
regional node that terminates access network and,
backbone network with a smaller number of richly connected switches
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Observations that Lead to Simplifications
Tremendous focus on protocols/protocol architecture, should also focus on networks and network architecture
Interplay between network architecture and protocol architecture
Architecture agnostic to technology trend Should leverage technology trends that enable simple network architecture
Box/Switch/Router centric distributed control has fundamental limitations, should also explore
Control architecture that can implement a wide range of network-wide
policies
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Robust, Simple Control and Management
Network is about coordination of switches Distributed state management Multiple goals
– Reachability
– Policy control
– Security
– Resiliency
– Traffic Engineering, load balancing
– VPN
Multiple layers (switching + optical) Diverse switching primitives (OXC, label switches, IP switches, vLAN
switches)
Status quo of control and management: extreme complex, non-linear and fragile
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Good Abstractions Reduce Complexity
All decision making logic lifted out of control plane
Eliminates duplicate logic in management plane
Dissemination plane provides a control channel to/from data plane
ManagementPlane
Control Plane
Data Plane
DecisionPlane
Dissemination
Data Plane
Configs
FIBs FIBs
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Development of the Elevator Pitch
Internet technology is far from being adequate to support 100x100 vision
Goal: dependable, scaleable, secure, and economic sustainable telecommunication infrastructure
It is already extremely complex
Solution: simplify, simply, simply!
Simplicity should also mean that the design is understandable
Three key ideas that may lead to simplification
Take advantage of structured network
Leverage and develop technologies that enable structured networks
Design simple and powerful network-wide control abstractions/mechanisms
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Why 100x100? Why not 1000x100?
Key is to focus us on an end goal of a network
Principles derived can be general
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Why Clean State Design?
A powerful research methodology that helps to crystallize the issues Many good examples in systems research that take one idea to extreme:
RISC, SmallTalk, NFS, IP
A mind set that may result in different research, e.g. Incremental approach to security
– How to detect and stop Blaster, Code Red?
Clean state design approach– What would be the fundamental capability of a strategic adversary?
– What are the fundamental limitations/possibilities of any network-based or host-based security mechanism?
– What should be the minimal & necessary set of layer 3 security mechanism?
A concrete and complete different design point highlights possibilities Understanding the target first helps to plan the trajectory of evolution
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Big Bets Research
We make big bets to get big breakthroughs
Visionary ideas carrying intellectual risk
Can’t predict outcomes in advance
The Christopher Columbus Effect
Randy Bryant: Dean of SCS, CMU“Strategic Vision for CS in CMU”
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Can We Make a Difference?
Monopoly positions in all technology areas
Microsoft in OS
Cisco in router
Intel in processor
Oracle in database
People are usually
too optimistic in prediction of two years out, but
too pessimistic in prediction of five or ten years out
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Can We Change IP and the Internet?
What is IP anyway? Service interface: services seen by VoIP, Web
Data plane (IPv4, IPv6 packet formats)
Control plane (OSPF, ISIS, BGP, LDP)
Management plane
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Learning from Ethernet Evolution Experience
Current Implementations:
Everything Changed Except Name and Framing
Ethernet
Conc..
Router
Server
WAN
HUB
Switch
•Switched solution
•Little use for collision domains
•80% of traffic leaves the LAN
•Servers, routers 10 x station speed
•10/100/1000 Mbps, 10gig coming: Copper, Fiber
WAN
LAN
Ethernet or 802.3
•Bus-based Local Area Network
•Collision Domain, CSMA/CD
•Bridges and Repeaters for distance/capacity extension
•1-10Mbps: coax, twisted pair (10BaseT)
B/R
Early Implementations
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How To Evolve?
One possible path to future Fix packet format: IP or IPv6 or Ethernet or MPLS frame
formats Evolve switch-switch protocols (NNI)
– control/management plane, where the intelligence is