Next Step In Signaling NSIS and Internet Routing Dynamics Charles Shen and Henning Schulzrinne Colum

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Next Step In Signaling (NSIS) and Internet
Routing Dynamics Charles Shen and Henning
Schulzrinne _at_ Columbia University in the City of
New York

• Project Description
• As part of the IETF NSIS working group, we are
  standardizing a protocol for signaling
  information about a data flow along its path in
  the Internet.
• The protocol supports various signaling
  applications, such as Quality of Service (QoS)
  and Network Address Translation (NAT) and
  Firewall traversal.
• The protocol design adopts a two-layer approach,
  a lower layer for transport, and an upper layer
  specific to each signaling application.
• We are looking specifically at the signaling
  transport layer, or Generic Internet Messaging
  Protocol for Signaling (GIMPS) as well as its
  interaction with IP routing.
• We conducted Internet routing dynamics
  measurement and evaluated route change detection
  methods in typical NSIS deployment models.

• Internet Routing Dynamics Analysis
• Route prevalence and persistence
• - single dominant route
• - significant site to site variation
• - adaptive approach for NSIS
• Different types of route changes
• - wide scales in time or location
• - majority no change of hop count
• - route splitting and load balancing
• Measurement accuracy
• - 10-min fixed vs. 2-hour exp.
• - may capture the same changes
• - may miss half of the changes.
• - still site-to-site variation
• Impact of multi-homing
• - AS level route changes
• - Asymmetric routing

• End to end Routing Measurement
• Traceroute for path characterization
• 24 Public servers located in US, Iceland,
  Netherlands, Australia, Germany, Switzerland,
  Bulgaria, Sweden and Thailand.
• Both independent, exponential interval (15/30
  min per site) and fixed interval (10 min per
  path) sampling
• Between April and August 2004

NSIS-Concerned Route Changes - the subset of
route changes that involve change of NSIS
Entities (NEs)
New path
Data flow direction
Old path

• NSIS Deployment Models and
• the TTL Monitoring Method
• AS model a central NE in each AS
• Entry model ingress routers are NEs
• Border model both ingress and egress routers
  are NEs
• Edge model access routers of source and
  destination sites are NEs
• TTL monitoring detected 40 - 90 route changes
  in different models

7DS Client

• Route Change Detection Methods
• Routing monitoring (BGP, OSPF)
• - Local trigger
• - Extended trigger
• Packet monitoring (TTL/Interface)
• - Connection-mode signaling messages
• - Data packets
• Datagram-mode probing

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• As part of the IETF NSIS working group we are
  standardizing a generic IP signaling protocol
  that separates the transport of the signaling
  from the application signaling (e.g., QoS, NAT
  traversal).

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