Arequipa, A network technology adapter

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Arequipa,A network technology adapter

• Presented by Beizhong Chen and Vincent Matossian
• Friday March 10th ,2000

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ATM Description

• Knits local and wide-area networks and services
  into a seamless whole
• Billing possible on per-cell basis
• Scalable - Works at different speeds and on
  different media
• Open-ended growth path - Not locked to any
  physical medium or speed

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Advantages of ATM

• Flexible bandwidth allocation
• Simple routing due to connection oriented
  technology
• Potential QOS (Quality Of Service) guarantees
• Compatibility-ATM can be transported over twisted
  pair, coax and fiber optics.

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Overview

• Motivation
• What is Arequipa?
• How does it work?
• Implementation
• Comparison to existing solutions
• Arequipa and the Web
• Extensions to servers and clients
• Example
• Conclusions

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Arequipa, IP over ATM Motivations

• To provide guaranteed QoS for IP over ATM today.
• With Arequipa, applications can request a
  dedicated SVC for all data exchanged between two
  sockets.

R3
R1
R2
ATM LAN
ATM WAN
ATM LAN
flow1
flow2
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Motivation

• Classical IP over ATM does not does not benefit
  from ATMs guaranteed quality of service,
• IP network support for QoS is planned (RSVP,
  NHRP) but will have to be deployed over the
  complete network before being available end-to-end

R1
R3
R2
ATM LAN
ATM WAN
ATM LAN
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What is Arequipa

• Arequipa allows applications to request a
  dedicated SVC for data exchanged between two
  sockets
• Arequipa provides two new socket primitives to
  applications
• Arequipa_preset Opens an end-to-end SVC and
  sends all data from the socket over that
  connection
• Arequipa_expect Allows to use incoming arequipa
  connections for the reverse direction

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Implementation

• In the protocol stack Arequipa is seen as one
  device, like ethernet or classical IP (CLIP)
• A pointer to the Arequipa device is put in the
  route cache of the sockets which use Arequipa. IP
  thus forwards the data to the Arequipa device.
• A pointer to the dedicated VPC is saved in the
  socket descriptor. It is used to send the data
  over the correct VPC.
• Signalling is done by the same entity as for IP
  over ATM

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Implementation (contd)

• Example Arequipa_preset

OS
applications
preset
set cache
socket layer
TCP / UDP
IP
setup
CLIP
Arequipa
VCC1
VCC2
VCC3
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Comparison
APP2
APP1
APP2
APP1
NHRP
RSVP
APP2
APP1
Class. IP
Class. IP
RSVP
NHRP
Class. IP
APP2
APP1
NHRP
APP2
APP1
APP2
APP1
Class. IP
RSVP
RSVP
Class. IP
RSVP_ATM
Class. IP
RSVP_ATM
NHRP
Arequipa
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Arequipa and the Web

• Using Arequipa each document can be downloaded
  with the QoS it needs
• Required QoS is specified in meta information of
  Web documents
• Web browsers put their ATM address in every
  request
• If a browser wants to receive a document over an
  Arequipa connection, it also indicates the socket
  on wich to send the document

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Arequipa and the Web (contd)

• When a server sees QoS in a document, ATM address
  and socket in a request, it sends the document
  using Arequipa
• When a server sees QoS in a document, ATM address
  in request but no socket, it send header of
  document over normal connection.
• Given the header with the QoS info, a browser can
  choose whether it wants to use Arequipa or not.
• Arequipa capable servers and browsers are fully
  compatible with standard servers and browsers.

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Example
browser
server
get batman.mpgATM-address 213121
pragma ATM-QoS-ServiceCBRpragma
ATM-QoS-PCR10Mbit/sContent-type video/mpeg
create socket Arequipa_expect(s) listen(s) accept(
s)
get batman.mpgATM-addrses 213121 pragma
socketTCP.8090
create socketArequipa_preset(s) connect(s) writ
e(s,batman)
batman.mpg
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Conclusion

• Arequipa can provide guaranteed QoS for point to
  point data flows within an ATM cloud.
• Arequipa runs on current ATM networks (UNI 3.1)
  and needs no network support (eg. NHRP, RSVP).
• Arequipa allows to provide today what RSVP over
  ATM (and NHRP) will only provide in the future.

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Status

• Arequipa support is part of the linux-atm
  distribution of LRC
• Arequipa capable browser, server and proxy server
  are available with source code
• For more information
  http//lrcwww.epfl.ch/arequipa/