Services Architectures

1
Services Architectures Network Intermediaries
and End-to-end Abstractions

• Dan Duchamp
• Stevens Institute of Technology
• Tilman Wolf
• University of Massachusetts Amherst

2
Outline

• Premise The next-generation Internet needs to do
  more than provide end-to-end bit pipes
• Three topics
• Network services and incentives (Dan)
• Implementation challenges (Tilman)
• Trust and naming (guest speaker Paul Francis)
• Process
• Questions
• Brief presentation of context
• Long discussion
• Comments and questions welcome anytime!

3
Network Services and Incentives
4
Questions

• What services should the network provide?
• Should the network offer service at the
  application level rather than at the datagram
  level?
• Should anybody be allowed to provide services or
  not (and thus reduce potential for spam,
  phishing, spyware, etc.)?
• Will ease/speed of new service deployment be as
  important in the future as it has been in the
  past? Will the rate increase or decrease?

5
Questions (cont.)

• Capitalists would like to know how should
  accounting/billing work?
• Should we construct a network that could, for
  example, bill per page view?
• Socialists would like to know how can
  "undesirable uses" of the Internet be limited?
• What is the appropriate position for network
  architects to take regarding the design of
  censor-able, tap-able, spy-able Internet?
• What is the right technical tradeoff point
  between (1) a "civilized" appropriately-governable
  Internet, and (2) an Internet permitted "free
  expression"?

6
Session Layer Management of Network Intermediaries

• Dan Duchamp
• Computer Science Department and
• Wireless Network Security Center (WiNSeC)
• Stevens Institute of Technology
• Hoboken, NJ

7
The Discrete Internet

• Original Internet
• Infrastructure supported by US government
• Users like-minded, like-behaving
• Intelligent hosts at edges of dumb routing fabric
• Current Internet
• Commercially owned
• Subject to government oversight

8
Why Deploy Intermediaries?

• Commercial incentives
• Added value avoid being dumb pipe
• Place service hosts closer to client hosts to
  improve latency (e.g., Akamai)
• Customer incentives
• Enforce customer policies on customer-owned
  networks (e.g., firewall)
• IP address flexibility/security (NAT)
• Government incentives
• Law enforcement surveillance

9
The Point Is

• Internet has already been broken into discrete
  pieces
• Situation is not going to change
• We can either complain about it (end-to-end
  zealots) or deal with it

10
Basic Idea

• End-to-end layer 5 (L5) session runs over
  sequence of layer 4 (L4) transport connections
• Intermediaries explicitly addressed, each
  terminates an L4 connection

11
Consequences

• Easier to manage intermediaries if they are
  explicitly addressed
• Easier to manage network too
• Transport connections now long-lived heavily
  usedthats how they work best
• Amortize Path MTU discovery
• Maintain sstresh/cwnd settings
• More statistical multiplexing less burstiness

12
Hypothesized Benefits

• Cleaner programming model
• Improved congestion control
• Improved core link utilization
• More efficient physical/routing design
• Improved session performance via pipeline
  parallelism
• Important qualification improved performance
  after session has been established
• Easier traffic engineering

13
Foreseen Technical Problems

• How to locate desired intermediate service?
• Session setup too slow
• Study buffer management
• How to manage intermediary state?
• Additional points of failure types of failures
• What is right app-intermediary control
  semantics/protocol?
• Want piecewise securityservice X should see
  only one part of payload, service Y only another
  part

14
Foreseen Philosophical Problems

• Unambitious just what we dont needanother hack
  to the socket/TCP/IP model
• Network is still pretty dumb should know more
  about session semantics?
• If L5 handles end-to-end delivery semantics, what
  does L4 do?

15
Relation to FIND/GENI

• Yes, its trueL5 is just a tweak, not a new
  architecture
• But gives a concrete base for experiments with
  certain architectural issues
• What is a service? Where is it implemented? Who
  really provides itnetwork or host?
• State management
• Semantics/protocol for control signaling between
  end system intermediary
• Mapping of function to layers

16
Questions

• What services should the network provide?
• Should the network offer service at the
  application level rather than at the datagram
  level?
• Should anybody be allowed to provide services or
  not (and thus reduce potential for spam,
  phishing, spyware, etc.)?
• Will ease/speed of new service deployment be as
  important in the future as it has been in the
  past? Will the rate increase or decrease?

17
Questions (cont.)

• Capitalists would like to know how should
  accounting/billing work?
• Should we construct a network that could, for
  example, bill per page view?
• Socialists would like to know how can
  "undesirable uses" of the Internet be limited?
• What is the appropriate position for network
  architects to take regarding the design of
  censor-able, tap-able, spy-able Internet?
• What is the right technical tradeoff point
  between (1) a "civilized" appropriately-governable
  Internet, and (2) an Internet permitted "free
  expression"?

18
Implementation Challenges
19
Questions

• If services are (partially) provided in the
  network, what is the appropriate "cut" between
  what is done in the network and what is done at
  the host? Does one cut fit all?
• How should services be accessed? Should the
  end-system application choose or should the
  network enforce service use?
• How much should the network know about data
  semantics?
• Is the web browser the "last application"? That
  is, every future service will have its host
  implementation as a browser plugin?

20
Questions (cont.)

• Should all services be visible to end-systems?
  Should all data modifications be reported to
  end-systems?
• Should communication between services be allowed?
• How should service state be handled?
• What services are necessary at the edges of
  networks with different operating principles
  (e.g., Internet to/from sensor net)

21
Service-Centric End-to-End Abstractions
inNext-Generation Networks

• Tilman Wolf
• Department of Electrical and Computer Engineering
• University of Massachusetts Amherst

22
Information vs. Data

• Current Internet considers data as unchangeable
  entity
• Information encoded on end-systems
• Network unaware of semantics
• End-systems want to transfer information
• Use of explicit information transfer semantics
• Network communicates and processes information in
  suitable way
• High-level semantics sufficient
• Streaming vs. random access
• Point-to-point vs. multipoint
• Interactive vs. canned
• Bandwidth-sensitive vs. delay-sensitive
• Requires network to do more than forward bits

23
Information Transfer and Data Services

• Processing of data not limited to end-systems
  anymore
• Data processing throughout the network
• Services
• Reliability
• Privacy
• Congestion control
• Caching
• Security (e.g., firewall, IPS/IDS)
• Quality of service
• Multicast
• Payload transcoding

24
Services

• Services can be combined for end-to-end
  information transfer
• Example 1
• Reliable and private communication
• Example 2
• Web caching

25
Services

• Example 3
• Content distribution and transcoding
• How can all this be implemented?

26
Service Platforms

• Network processors are specialized processing
  system for packet processing
• System-on-a-chip multiprocessor
• Optimized for networking workloads
• Typical configurations
• Tens to hundreds of processing engines
• Multiple memory interfaces, co-processors
• Commercially available
• Intel, AMCC, Freescale, Hifn, etc.

Control processor
Multiple data path processors
Memory
I/O
27
Service Specification

• Abstraction for services along connection
• Similar to UNIX pipe concept
• Example 1 transfer between nodes
• N1 gt N2
• Example 2 reliable transfer between nodes
• N1 TCP_TX gt N2 TCP_RX
• Example 3 transcoding at arbitrary intermediate
  node
• N1 TCP_TX gt TXP_RX TRANSCODE TCP_TX
  gt N2 TCP_RX
• Leads to placement problem
• Assignment of processing tasks to underlying
  infrastructure

28
Service Placement

• Mappingproblemappears onall layersof system
• End-to-end
• Routers
• Port processors

29
Service Placement

• Layered graph approach
• Single metric for communication and computation

Source of connection
Extra layer with vertical processing steps
Destination of connection
30
Service Placement

• Ramdomized mapping approach
• Random placement
• Fast analytics evaluation
• Repeat
• Performance
• Incrementallybetter results

31
Summary and Next Steps

• Abstraction based on information and data
  services
• Network can provide best setup for end-to-end
  communication
• Requires processing capabilities throughout the
  network
• Tackle implementation issues
• Service specification
• Service placement
• Prototype demonstration

32
Questions

• If services are (partially) provided in the
  network, what is the appropriate "cut" between
  what is done in the network and what is done at
  the host? Does one cut fit all?
• Is the web browser the "last application"? That
  is, every future service will have its host
  implementation as a browser plugin?
• How should services be accessed? Should the
  end-system application choose or should the
  network enforce service use?
• How much should the network know about data
  semantics?

33
Questions (cont.)

• Should all services be visible to end-systems?
  Should all data modifications be reported to
  end-systems?
• Should communication between services be allowed?
• How should service state be handled?
• What services are necessary at the edges of
  networks with different operating principles
  (e.g., Internet to/from sensor net)

34
Trust and Naming
35
Questions

• Should the Internet provide "trust"?
• Should we have source/identity validation?
• If application creators (apparently) want
  source/identity validation, why not provide it?
• Is a better tradeoff between trust/flexibility
  achievable? How?
• What should we use to identify end-system
  processes, users, etc.?
• How should we maintain identity mapping under
  mobility?
• Should the network understand the semantics of a
  data exchange?

36
End-Middle-End Architectures

• Paul Francis
• Cornell University

37
Most basic function in the Internet

• Send a packet from an app on one host to an app
  on another host
• Often doesnt work
• Sometimes an unwanted connection can be made
• Often a wanted connection cannot be made

38
What is the problem?

• IPv6 folks think (thought?) the problem is NATs
• But firewalls often err
• Port number only meaningful at the endhost
• Addresses change
• Shouldnt access control be done at the hosts?
• Argument of IPv6ers and E2E purists

39
We still need firewalls

• DoS
• Privacy of endhost
• IP address gives away private information
• Study of 100K mobile dyndns users
• Reality of infrastructure evolution
• Sometimes its just easier to put a box in the
  middle

40
Other reasons to put stuff in the middle

• Proximity (web caches)
• Benefits of scale (spam filtering)
• Centralized control
• Ease of deployment

41
End-Middle-End architecture

• Need an architecture that allows all stakeholders
  in a connection to
• Know what is going on
• Assert their policies
• Access control policies
• Steering policies
• Security policies
• Transport policies

42
Do we need a blank slate?

• Maybe
• But lots of progress can be made on the existing
  infrastructure
• Formed EME IRTF Research group
• Initiated by Francis and Handley
• Chaired by Tilman Wolf
• Early stages

43
EME requirements

• Authentication, access control, and privacy
• Name-based
• Middlebox discovery and control
• Steering through middleboxes
• Anycast, multicast
• Mobility, multihoming
• Multi-party negotiation
• Performance
• Incremental deployability

44
EME Architecture

• Demote 5-tuple connection
• Ephemeral
• Use name-based signaling to manage connections
• Make this name-based approach part of the common
  sockets API

45
Slightly more detail

• Two types of signaling
• Off-path
• Used when IP address(es) not known
• Or to obtain (optional) credentials
• SIP is a good model
• On-path
• Used when IP address(es) known and have
  credentials
• Get through firewalls
• Steer connections

46
Questions

• Should the Internet provide "trust"?
• Should we have source/identity validation?
• If application creators (apparently) want
  source/identity validation, why not provide it?
• Is a better tradeoff between trust/flexibility
  achievable? How?
• What should we use to identify end-system
  processes, users, etc.?
• How should we maintain identity mapping under
  mobility?
• Should the network understand the semantics of a
  data exchange?