MPLS

1
MPLS PATH PROTECTION
Ashish Gupta (98130) Ashish Gupta (98131)
Under guidance of Prof. B. N. Jain
2
Overview

• What is MPLS ?
• Path Protection in MPLS Networks
• Existing Work
• Our Scheme Segment Based Protection
• Research Issues
• Present Status
• Targets

3
What is MPLS ?

• Current IPs Routing Model
• Each router makes independent forwarding
  decisions based on destination IP address
• MPLS Multi Protocol Label Switching
• Applies concept of VC routing
• Packet forwarding is done based on Labels
• FEC Destination address prefix, Traffic
  Engineering tunnel, Class of Service.

4
Path Protection in MPLS

• Todays IP Routing Model does not provide
  guaranteed services gt no path protection
  required
• MPLS provides guaranteed services gt Path needs
  to be protected
• Protection against Link Failure, Node Failure
• Parameters Involved Fault detection, Fault
  localization, Notification, New LSP setup

5
Existing Work

• Global Path Protection
• Local Path Protection
• Link Failure
• Node Failure
• 11 Path Protection
• Sharing Modes - 1 1, 1 N, M N

Backup LSP
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Segment Based Protection (SBP)
Our Approach
Divide the path into segments
Egress
Original LSP Backup Paths
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Advantages of SBP

• Closest bound on our restoration time (Global)
• Need to reserve less backup paths (Local)
• Less Rejection Rate (More capacity of the
  network)
• Flexible Example heterogeneous core
• Includes Global/Local Path Protection as special
  cases
• User of the service (SLA) can set the delay.
  More delay gt larger segments gt less resources
  (cost)

8
Research Issues

• A suitable method to detect , locate and notify
  failure to the segment head node.
• Signaling schemes - LDP , RSVP - TE
• Detection Tradeoff between periodicity and
  segment length
• Notification Performance
• An algorithm for Segmentation based approach
• Constrained based segmentation setup basis ?
• How much network state information do we need ?
• Online vs Offline Algo
• More considerations in multiple paths

9
Research Issues

• Making the backup paths
• How does our scheme differs from standard methods
  of making backup paths
• Constraints will be superset of constraints
  needed for active path
• Avoid looping
• Amount of Reservation needed for backup paths
• Compare to other algorithms like local
  restoration
• No. of rejections in the system
• Do simulations for above and report the results
• Report advantages

10
Research Issues

• Managing the Labels
• Ensuring correct labeling mechanisms when backup
  path is used
• Buffering in our scheme to reduce packet loss
  during switchover time
• Buffer sizes- depending on segment metrics
• Buffer at each node or only at segment head
  nodes. ?

11
Present Status

• Understanding the problem
• Literature survey
• Identified Research areas
• Constrain Based Routing

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Future Targets

• December 1st 2001
• Error detection and notification issues in
  Segment based protection (SBP)
• Work out example scenarios using SBP
• An algorithm for SBP for different types of basis
• Label management issues in SBP
• May 1st 2002
• Simulations to test performance and resource
  usage vs. other schemes
• Explore other issues like Buffering
• More simulation and analysis for comparison and
  advantages
• Documenting our work

13
Literature Survey

• Segment based path protection in MPLS networks
  with bounds on packet lossby Prof B N Jain
  Satish Tripathi
• IEEE Comms
• Designing Multiprotocol label switching networks
  by Jeremy Lawrence (Cisco systems)
• Generalized MPLS an overview of signal
  enhancement and recovery techniques by Ayan
  Banerjee, john Darke, et al.
• MPLS breaking throughby bill Michael
• Papers
• Dynamic routing of locally restorable Banddwidth
  Guranteed tunnels using aggregated link usage
  informationby Murali Kodilam, T. V. Lakshman
  (bell labs.)

14
Literature Survey

• RFCs Internet Drafts
• MPLS Architecture RFC (RFC 3031)
• draft-ietf-mpls-recovery-frmwrk-03
• Path Protection
• draft-andersson-fast-reroute-frmwrk-00
• draft-haskin-mpls-fast-reroute-03
• draft-iwata-mpls-shared-fastreroute-00
• draft-shandilya-fault-tolerant-lsp-00
• draft-shew-lsp-fast-restoration-00
• draft-kini-restoration-shared-backup-00
• draft-gan-fast-reroute-RSVP-detours-00

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Literature Survey

• Presentations on MPLS from CISCO
• Documents on constrained based routing