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Next generation Optical Networks for Broadband European Leadership. NOBEL. Multilayer resilience WP2.1 19-21 september 2005. Benoît LEMOINE France Telecom R&D. Next generation Optical Networks for Broadband European Leadership. NOBEL. FT study on multilayer resilience.
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Next generation Optical Networks for Broadband European Leadership NOBEL Multilayer resilienceWP2.1 19-21 september 2005 Benoît LEMOINE France Telecom R&D
Next generation Optical Networks for Broadband European Leadership NOBEL FT study on multilayer resilience • Multilayer network scenario description • Single layer distributed restoration performance • Multilayer restoration triggering • Conclusions
Next generation Optical Networks for Broadband European Leadership NOBEL Multilayer network scenario (1/2) • Multi layer network • Higher layer network : IP/MPLS with TE extensions • Lower layer network : SDH with ASON functions • Adaptation between layer networks • IP/MPLS traffic is multiplexed into • Generic Framing Procedure (G.7042), • over SDH Virtual Concatenation (G.707). • SDH VC4-xv Virtual Concatenation Groups are supported by • SDH VC4 network connections, • using Link Capacity Adjustment scheme (G.7041) to adapt the VCG size to the number of active VC4.
Next generation Optical Networks for Broadband European Leadership NOBEL Multilayer network scenario (2/2) • Types of Quality of Resilience • A Services with very small tolerable interruption time • supported by 1+1 protected NC. • B Services with guaranteed bandwidth, tolerating short interruptions • carried by restorable MPLS-TE LSP over VCG with restorable NC. • C Services with no guaranteed bandwidth, tolerating short interruptions • carried by basic restorable MPLS LSP over VCG with restorable NC. • D Services with no guaranteed bandwidth, tolerating large interruptions • carried as IP traffic, without any MPLS LSP, on the shortest network path. • Study focuses on the choice between • Restore MPLS-TE LSP ? • Restore MPLS LSP ? • Restore NC ?
Next generation Optical Networks for Broadband European Leadership NOBEL Considered Types of QoR MPLS-TE LSP LSP LSP MPLS IP MPLS Restoration VC4-xv VC4-xv GFP GFP VCAT+LCAS VCAT VC4 VC4 VC4 VC4 VC4 VC4 SDH Restoration SDH 1+1 Protection STM STM QoR B, C and D QoR A (not considered)
Next generation Optical Networks for Broadband European Leadership NOBEL Single layer restoration • Distributed restoration performance on 10-20 nodes network • Distribution approximated by • Histogram approximated by • The restoration time constant T increases linearly with the number of network connections to restore at the same time
Next generation Optical Networks for Broadband European Leadership NOBEL Multilayer restoration triggering • Minimize the number of NC and LSP to restore • Suggested iterative scheme • 1 If no MPLS-TE LSP or MPLS LSP do not restore NC. • 2 If only MPLS LSP are carried over the VCG restore at most one NC. • 3 If MPLS-TE LSP and MPLS LSP are carried over the virtual concatenation group, and the remaining VCG bandwidth is smaller than the sum of bandwidth reserved for MPLS-TE LSP • a. If the highest bandwidth reserved by an MPLS-TE LSP is higher than the incremental bandwidth offered by a single NC, restore that MPLS-TE LSP. Go to step 2. • b. If not, then restore as many NC as needed to reach the total reserved bandwidth.
Next generation Optical Networks for Broadband European Leadership NOBEL Multilayer restoration triggering • Restore NC in two steps • Suggested iterative scheme • 1 If no MPLS-TE LSP or MPLS LSP do not restore NC. • 2 If only MPLS LSP are carried over the VCG restore at most one NC. • 3 If MPLS-TE LSP and MPLS LSP are carried over the virtual concatenation group, and the remaining VCG bandwidth is smaller than the sum of bandwidth reserved for MPLS-TE LSP • a. If the highest bandwidth reserved by an MPLS-TE LSP is higher than the incremental bandwidth offered by a single NC, restore that MPLS-TE LSP. Go to step 2. • b. If not, then restore as many NC as needed to reach the total reserved bandwidth. • 4 After a proper temporisation, restore the still impacted NCs.
Next generation Optical Networks for Broadband European Leadership NOBEL Conclusions • Performance of a single layer distributed restoration • Increases with the number of Network Connections to restore. • Multilayer restoration triggering • Restore MPLS-TE LSP for which reserved bandwidth is higher than the basic SDH Network Connection bandwidth (i.e. 155 Mbps). • Restore SDH NC to protect basic MPLS LSP and MPLE-TE LSP for which reserved bandwidth is lower than SDH NC bandwidth. • Split impacted SDH NC in two sets • Restore immediately the first set of NC needed to satisfy QoR. • Restore after a proper temporisation the second set of NC to increase non guarantied bandwidth back to the highest possible value without any time constraints. • Implementation • Coordination between SDH network and MPLS network is needed.