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Ashish Gupta (98130)
Ashish Gupta (98131)
Under guidance of
Prof. B. N. Jain
What is MPLS ? Path Protection in MPLS Networks Existing Work Our Scheme: Segment Based Protection Research Issues Present Status Targets
Current IP’s 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.
Today’s IP Routing Model does not provide guaranteed services => no path protection required
MPLS provides guaranteed services => Path needs to be protected
Protection against: Link Failure, Node Failure Parameters Involved: Fault detection, Fault localization,
Notification, New LSP setup
R2
R3
R6
R4R8
R7
R1
R10
R9
R5
• Global Path Protection
• Local Path Protection
• Link Failure
• Node Failure
• 1+1 Path Protection
• Sharing Modes - 1 : 1, 1 : N, M : N
r
Original LSP
Backup LSP
Segment Based Protection (SBP)
Original LSP
Backup Paths
Egress
Ingress
Seg. 1Seg. 2
Seg 3Seg. 4
Divide the path into segments
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 => larger segments => less resources (cost)
• 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
• 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
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. ?
Understanding the problem Literature survey Identified Research areas Constrain Based Routing
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
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.)
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
Literature Survey
Presentations on MPLS from CISCO Documents on constrained based routing