IXP-resident Stream Handlers

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IXP-resident Stream Handlers Ada Gavrilovska, Dr.
Karsten Schwan, Hailemelekot Seifu, Himanshu Raj,
Ola Nordstrom

• Stream Handlers
• Stream Handler - lightweight computational unit
  executed by the IXPs microengines which operates
  on both, packet header and payload data
• Use of efficient fragmentation/reassembly
  protocol to compose application-level data in the
  IXP memory
• Use of self-describing data formats to interpret
  payload data
• Stream handlers can
• be applied on fully assembled application-level
  data, or
• be combined with underlying protocol's receive-
  and/or transmit-side when operating on localized
  portions of the data
• coexist at various points on data path
• Runtime configuration and control through
  host-IXP interface

Host - Attached NP node building block in
overlay networks, interactive grids, p2p systems,
cluster servers

• Objectives
• Enable application-level processing at the NP
  level for streaming applications
• Utilize available headroom on data path through
  NP to implement additional functionality
• Tightly couple host with attached IXP
• Distribute processing among IXP µEngines and
  host based on resource availability.
• Enable dynamic customizations which match
  changes in application interests and network
  conditions

HOST
IXP NP
Applications commercial (OIS), scientific (RT
collaborations), dynamic web applications
(delivery of camera-captured data) Stream
handler examples application-level filtering,
mirroring, stream differentiation, format
translation, downsampling
performance gains stem from host CPU offloading,
and reduction of loads imposed on underlying
memory and network infrastructure, and vary
depending on types of data and processing involved
Stream Handlers in the IXP

• Dynamic Reconfiguration
• necessary to best utilize available resources and
  meet dynamic client needs and dynamic platform
  conditions.
• Dynamic selection of handler functionality
• currently through use of parameterizable handlers
  or by selecting from a set of existing handlers
• assessing possibilities for runtime deployment of
  new codes
• Handler composability
• implement application-level services as
  compositions of multiple stream handlers existing
  at various points on data path
• well-defined interfaces and points of handler
  invocation
• Admission control
• monitor use of resources such as headroom
• consider both IXP- and host-side deployment

client-specific multicast implemented by Rx-side
mirroring handler and a Tx-side filtering, data
translation, or other handler.
With Tx-side stream handlers client-specific
multicast is implemented at low costs, and CPU
and network resources are preserved