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Overview of Future Internet Routing Activities Michael Menth - - PowerPoint PPT Presentation

Jul 14, 2023 29 likes •225 views

Institute of Computer Science Department of Distributed Systems Prof. Dr.-Ing. P. Tran-Gia Overview of Future Internet Routing Activities Michael Menth www3.informatik.uni-wuerzburg.de Overview Why does the Internet not scale?

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www3.informatik.uni-wuerzburg.de

Institute of Computer Science Department of Distributed Systems

  • Prof. Dr.-Ing. P. Tran-Gia

Overview of Future Internet Routing Activities

Michael Menth

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2 Overview of Future Internet Routing Activities Michael Menth

Overview

 Why does the Internet not scale?  Locator/identifier split  Existing protocol proposals  Early research  Conclusions

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3 Overview of Future Internet Routing Activities Michael Menth

Internet Scalability

 DFZ (default-free zone)

  • Core of the Internet
  • No default routes for packets exist
  • Forwarding tables are large

 Provider aggregatable (PA) address space

  • Provider owns IP addresses
  • Subspace may be used by customers for the duration of their contract
  • Provider change requires renumbering
  • Aggregation of IP addresses for several customers facilitates routing

scalability  Provider independent (PI) address space

  • Customer owns IP addresses assigned by Internet registries
  • No renumbering of IP addresses necessary upon change of ISPs
  • No aggregation of IP addresses possible, prefixes require extra

entries in forwarding tables expensive routes  More: http://www.ripn.net:8080/nic/ripe-docs/ripe-127.txt

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4 Overview of Future Internet Routing Activities Michael Menth

Why do we need a new Internet routing?

 Quadratic or exponential growth (worst case)  Bad !!! BGP table sizes seen at one router

[Source: CIDR Report IPv4 – http://www.cidr-report.org]

Quadratic or even exponential growth!

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5 Overview of Future Internet Routing Activities Michael Menth

What if we do nothing? Wouldn’t IPv6 help us?

[Source: IETF Meeting http://www.vaf.net/~vaf/apricot-plenary.pdf]

Numbers exceed the FIB limits of many currently-deployed routers!

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6 Overview of Future Internet Routing Activities Michael Menth

Design Goals for Scalable Internet Routing

 http://www.ietf.org/internet-drafts/draft-irtf-rrg-design-goals-01.txt

  • Improved routing scalability

(required)

  • Routing security

(required)

  • Deployability

(required)

  • Routing quality

(strongly desired)

  • Scalable support for multihoming

(strongly desired)

  • Scalable support for traffic engineering

(strongly desired)

  • Simplified renumbering

(strongly desired)

  • Decoupling location and identification

(desired)

  • Scalable support for mobility

(desired)

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7 Overview of Future Internet Routing Activities Michael Menth

Scalability of Internet Routing: Principle Idea

 Internet addresses initially assigned in hierarchical manner  Address aggregation for interdomain routing  Initially small forwarding tables

R0 R0 R1 R1 Provider ider X Provider ider Y 1.0/1 /16 1.1/1 /16 2.0/1 /16 2.1/1 /16

Prefix NHop AS 1/8 X 2/8 Y Forw rwar ardi ding g table e of R1

Core

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8 Overview of Future Internet Routing Activities Michael Menth

Scalability of Internet Routing: Multihoming & Peering

 Multihoming and peering destroy hierarchical structure  Sizes of forwarding tables increase

R0 R0 R1 R1 Provider ider X Provider ider Y 1.0/1 /16 1.1/1 /16 2.0/1 /16 2.1/1 /16

Prefix NHop AS 1.0/16 X 1.1/16 Y 2/8 Y Forw rwar arding ing table e of R1

Core

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9 Overview of Future Internet Routing Activities Michael Menth

Scalability of Internet Routing: Provider Change

 Provider changes destroy hierarchical address structure  Sizes of forwarding tables increase

R0 R0 R1 R1 Provider ider X Provider ider Y 1.0/1 /16 1.1/1 /16 2.0/1 /16 2.1/1 /16

Prefix NHop AS 1.0/16 X 1.1/16 Y 2.0/16 Y 2.1/16 X Forw rwar ardi ding g table e of R1

Core

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10 Overview of Future Internet Routing Activities Michael Menth

Scalability of Internet Routing: Assignment of New Address Blocks

 Non-hierarchical assignments of scarce IPv4 address blocks destroy hierarchical address structure  Sizes of forwarding tables increase

R0 R0 R1 R1 Provider ider X Provider ider Y 1.0/1 /16 1.1/1 /16 2.0/1 /16 2.1/1 /16

Prefix NHop AS 1.0/16 X 1.1/16 Y 2.0/16 Y 2.1/16 X 3.0/16 Y Forw rwar arding ing table e of R1

3.0/1 /16 Core

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11 Overview of Future Internet Routing Activities Michael Menth

Observation: IP Addresses are Locators & Identifiers

 Causes

  • Change of the location of end systems
  • Multihoming
  • New address blocks

 Effects

  • Destroy hierarchical address structure
  • Change forwarding tables
  • Increase forwarding table sizes

 IP addresses

  • Used by forwarding to locate end systems
  • Identify end systems and must not be changed to achieve routing

scalability Combined locator and identifier function of IP addresses has negative impact on Internet scalability

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12 Overview of Future Internet Routing Activities Michael Menth

Solution: Locator/Identifier Split

 Split addresses in

  • dynamically assigned locator

part

  • statically assigned identifier

part  Completion of interdomain-routable addresses

  • Mapping service assigns

locators to identifiers

A

Mappi ping ng service ice

B

R0 R0 R1 R1 Provider ider X Provider ider Y

B

Core

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13 Overview of Future Internet Routing Activities Michael Menth

Locator/Identifier Split: Principle Idea

R0 R0 R1 R1 Provider ider X Provider ider Y 1.0/1 /16 1.1/1 /16 2.0/1 /16 2.1/1 /16

Identifier prefix Locator 1/8 X 2/8 Y Table le of mappin ing service ce

 Address aggregation improves scalability of mapping service (MS)  Table size of MS not required to be small; intelligent implementation

  • Similarly to DNS
  • Using DHTs

Core

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Locator/Identifier Split: Multihoming & Peering

 Mapping service can be used for traffic egineering

  • Answer request with X or Y depending on source address of

request

R0 R0 R1 R1 Provider ider X Provider ider Y 1.0/1 /16 1.1/1 /16 2.0/1 /16 2.1/1 /16

Identifier prefix Locator 1.0/16 X 1.1/16 X, Y 2/8 Y Table le of mappin ing service ce

Core

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Locator/Identifier Split: Provider Change

 Provider changes invisible to Internet-internal routing structure  Just mapping service changes

R0 R0 R1 R1 Provider ider X Provider ider Y 1.0/1 /16 1.1/1 /16 2.0/1 /16 2.1/1 /16

Identifier prefix Locator 1.0/16 X 1.1/16 X, Y 2.0/16 Y 2.1/16 X Table le of mappin ing service ce

Core

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Locator/Identifier Split: Assignment of New Address Blocks

 Provider changes invisible to Internet-internal routing structure  Just mapping service changes

R0 R0 R1 R1 Provider ider X Provider ider Y 1.0/1 /16 1.1/1 /16 2.0/1 /16 2.1/1 /16

Identifier prefix Locator 1.0/16 X 1.1/16 X, Y 2.0/16 Y 2.1/16 X 3.0/16 Y

3.0/1 /16

Table le of mappin ing service ce

Core

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Protocol Proposals Implementing Locator/Identifier Split

 Some recent approaches (not a complete list!)

  • Locator/ID Separation Protocol (LISP)

http://www.ietf.org/internet-drafts/draft-farinacci-lisp-01.txt

  • A Proposal for Scalable Internet Routing & Addressing (eFIT)

http://www.ietf.org/internet-drafts/draft-wang-ietf-efit-00.txt

  • The IPvLX Architecture

http://www.ietf.org/internet-drafts/draft-templin-ipvlx-08.txt

  • Internet Vastly Improved Plumbing (IVIP)

http://www.firstpr.com.au/ip/ivip/

  • HLP: A Next Generation Interdomain Routing Protocol

http://www.cs.ucl.ac.uk/staff/M.Handley/papers/hlpsigcomm.pdf

  • Scaling IP Routing with the Core Router-Integrated Overlay (CRIO)

http://www.cs.cornell.edu/People/francis/icnp06-crio.pdf  More at the next meeting of the RRG, July 27th, collocated with IETF-69: http://www3.tools.ietf.org/group/irtf/trac/wiki/RoutingResearchGroup

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Early Research

 Bruno Quoitin, Luigi Iannone, Cédric de Launois, and Olivier Bonaventure: Evaluating the Benefits of the Locator/Identifier Separation, MobiArch Workshop at Sigcomm 2007, http://inl.info.ucl.ac.be/system/files/MobiArch07-CRV.pdf  Luigi Iannone and Olivier Bonaventure: Locator/ID Separation: Study on the Cost of Mappings Caching and Mappings Lookups, technical report, http://inl.info.ucl.ac.be/system/files/TechReport-LISP-Cost.pdf  Daniel Massey, Lan Wang, Beichuan Zhang, and Lixia Zhang: A Scalable Routing System Design for Future Internet, IPv6 Workshop at Sigcomm 2007, http://www.cs.ucla.edu/~lixia/papers/07SIG_IP6WS.pdf  Olivier Bonaventure: Reconsidering the Internet Routing Architecture, Internet Draft, http://www.ietf.org/internet-drafts/draft- bonaventure-irtf-rrg-rira-00.txt

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Conclusions

 Scalability problems in current interdomain routing recognized  Routing research group (RRG) in IRTF keeps track of that issue  Locator/identifier split seems to be one solution  Several protocol proposals based on this concept  Clean slate has more freedom!  New research opportunities

  • Scalability
  • Architectures for mapping services
  • Caching performance
  • Traffic engineering
  • Resilience

 Just the beginning of future Internet routing!