All Rights Reserved © Alcatel-Lucent 2006, ##### Scalability of IP/MPLS networks Lieven Levrau 30 th April, 2008 France Telecom, Cisco Systems, uawei Technologies, Telekomunikacja Polska S.A. ECI Telecom, Alcatel-Lucent dsl ppt Benchmarking Carrier Ethernet Technologies Workshop Session AII.1: PW/MPLS Krakow, Poland

All Rights Reserved © Alcatel-Lucent | Session AII.1 | April 2008 Agenda 1.MPLS control plane: Scaling the IGP to each scenario 2.MPLS transport tunnels: Scaling MPLS to each scenario

All Rights Reserved © Alcatel-Lucent | Session AII.1 | April 2008 Use cases Services to be offered by the IP/MPLS network:  L2VPN P2P (VPWS)  for mobile backhauling, non-routable residential traffic  L2VPN P2MP or MP2MP (VPLS)  for enterprise customers  L3VPN (IPVPN)  for routable residential traffic 3 orders of magnitude for deployment scenarios:  Scenario 1: 1k PE nodes  Scenario 2: 10k PE nodes  Scenario 3: 100k PE nodes

All Rights Reserved © Alcatel-Lucent | Session AII.1 | April MPLS control plane: Scaling the IGP to each scenario

All Rights Reserved © Alcatel-Lucent | Session AII.1 | April 2008 IGP scalability with 1k nodes A single area is sufficient for the IGP  ISIS or OSPF are eligible Routing ISIS or OSPF PE P ISIS or OSPF P L2 ISIS IP/MPLS L2 ISIS area

All Rights Reserved © Alcatel-Lucent | Session AII.1 | April 2008 IGP scalability with 10k nodes IP/MPLS L2 ISIS area IP/MPLS L1 ISIS area Multiple areas are required for the IGP  ISIS or OSPF are eligible Area Border Routers are required to control redistribution between areas  Routes are aggregated  Only Loopback addresses from one area are redistributed into other areas IP/MPLS L1 ISIS area IP/MPLS L1 ISIS area ABR Routing ISIS PE P P ISIS L1 ISIS P ISIS L2 ISISL1 ISIS PPP

All Rights Reserved © Alcatel-Lucent | Session AII.1 | April 2008 IGP scalability with 100k nodes IGP discontinuity is required:  Different instances of a single IGP  or different IGPs  or different AS IP/MPLS L2 ISIS area IP/MPLS L1 ISIS area IP/MPLS L1 ISIS area IP/MPLS L1 ISIS area ABR Routing ISIS PE P P ISIS L1 ISIS P ISIS L2 ISISL1 ISIS PPP PE IGP RIP IP/MPLS

All Rights Reserved © Alcatel-Lucent | Session AII.1 | April MPLS transport tunnels: Scaling MPLS to each scenario

All Rights Reserved © Alcatel-Lucent | Session AII.1 | April 2008 CAC and sub-100ms resiliency require MPLS traffic engineering:  TE-LSPs (RSVP-TE signaled LSP) as the technology for MPLS transport tunnels Otherwise :  LDP-LSPs (LDP signaled LSP) as the technology for MPLS transport tunnels For each network segment, either TE-LSP or LDP-LSP need to be chosen. Needs for QoS and resiliency drive the choice for the LSP technology

All Rights Reserved © Alcatel-Lucent | Session AII.1 | April 2008 For LDP-LSPs, a flat VPN model is sufficient (RFC 5036) For TE-LSPs, the use of hierarchical MPLS-TE is required (RFC 4206) For L3VPN, BGP Route Reflectors are required (RFC 4364) Scaling up to 1k Provider Edge nodes Routing LSP label allocation ISIS or OSPF PE P PW label allocation targeted LDP ISIS or OSPF P LDP or RSVP-TE L3VPN label allocation and route distribution IP/MPLS L2 ISIS area RR MP-BGP

All Rights Reserved © Alcatel-Lucent | Session AII.1 | April 2008 Scaling up to 10k Provider Edge nodes Inter-area support is required (within a single MPLS domain) :  draft-ietf-mpls-ldp-interarea-03.txt  Allows to setup LSPs across IGP areas without having to distribute in the IGP each /32 PE loopback => ABRs aggregate routes to reach loopback addresses IP/MPLS L2 ISIS area ABR Routing (IGP) PE L1 ISIS L2 ISIS P P LSP label allocation PW label allocation targeted LDP LDP L3VPN label allocation and route distribution / / /16 Redistribution between IGP areas Label for /32 RR MP-BGP RR IP/MPLS L1 ISIS area IP/MPLS L1 ISIS area

All Rights Reserved © Alcatel-Lucent | Session AII.1 | April 2008 Scaling up to 100k Provider Edge nodes L2 ISIS area L1 ISIS areas ABR PSN tunnel MPLS service segmentation is required (multiple MPLS domains):  For VPWS, multi-segment PW are required:  draft-ietf-pwe3-segmented-pw-07.txt  For multipoint L2VPN, hierarchical VPLS are required:  RFC 4762 Such segmentations alleviate issues of number of LSPs in core network L3VPN not addressed in this presentation PW2 PW3 PW4 MS-PW T-PE MS-PW T-PE S-PE Hub-PW Spoke-PW Spoke-PWs VPLS Core PE VPLS Core PE VPLS Edge PE VPLS Edge PE T-LDP S-PE Distinct IGP Or distinct IGP instance PW1 VPLS Core PE Hub-PW T-LDP L1 ISIS areas

All Rights Reserved © Alcatel-Lucent | Session AII.1 | April 2008 Proposition for WT-145 To enable the IP/MPLS network to scale up to 1k/10k/100k PE nodes, the following requirements are proposed to be added into WT-145 modules: IP Routing Module (IRM)  IGP (ISIS or OSPF) supporting multiple areas and multiple instances  Area border routers if the node is between two IGP areas MPLS LSP module (MLM)  TE-LSP (with RSVP-TE signaling: RFC 3209 if CAC and sub-100ms resiliency is required) with RFC 4206  LDP-LSP (RFC 5036) with draft-ietf-mpls-ldp-interarea-03.txt MPLS L2VPN service module (M2M)  RFC 4446 and 4447 for point to point L2VPN  draft-ietf-pwe3-segmented-pw-07.txt, for P2P L2VPN  RFC 4762, for multipoint L2VPN MPLS L3VPN service module (M3M)  RFC 4364: MP-BGP and route reflectors

All Rights Reserved © Alcatel-Lucent | Session AII.1 | April 2008 Thank you

All Rights Reserved © Alcatel-Lucent | Session AII.1 | April 2008 Backup Material

All Rights Reserved © Alcatel-Lucent | Session AII.1 | April 2008 Solutions' family for scaling MPLS Single MPLS domain solution  Flat VPN architecture: end-to-end PSN tunnels, PEs at the MPLS edges Multiple MPLS domain solutions  Network segmentation with the intervention of border routers (ASBRs or ABRs) in MPLS label exchange and MPLS traffic forwarding  Still PSN tunnels between ultimate PEs (Flat VPN architecture), but segmented on the infrastructure level  Service segmentation with the introduction of intermediate PEs  PSN tunnels between ultimate PEs and intermediate PEs Several solutions  Each solution solves a set of issues  All these solutions can coexist

All Rights Reserved © Alcatel-Lucent | Session AII.1 | April 2008 Overview of IETF solutions' families Number of PEs Segmented routing plan Single MPLS domainMultiple MPLS domains Flat VPN (end-to-end LSPs between ultimate PEs) Service segmentation (intermediate PEs) LDP-LSPsTE-LSPs Network segmentation 1k Mono-AS, Mono-areaNo added feature required (distribution of IP/32 addresses into the IGP) Full mesh of TE-LSPs possible with hierarchical TE (RFC 4206) (5) (3) Not neededNot needed as transport LSPs are concerned 10k Mono-AS, Multi-area LDP inter-area: draft-ietf-mpls-ldp- interarea-01.txt can be combined with MP-BGP L2VPN (RFC4761) for flat L2VPN, wrt signaling scalability Not feasible due to the number of LSPs, if full mesh required (1) as PSN tunnels to be noted that LDP-LSPs as PSN tunnels can be nested into some set of smaller TE-LSPs (3) LDP (or RSVP-TE) + BGP: RFC 3107 Carrying Label Information in BGP-4 LDP Aggregate FEC : draft-swallow-mpls- aggregate-fec-00.txt and draft-swallow-isis- detailed-reach-00.txt (4) can be combined with MP-BGP L2VPN (RFC4761), wrt signaling scalability MS-PW with FEC129: draft-ietf-pwe3-segmented-pw- 06.txt HVPLS RFC4762 HVPLS associating RFC4762 and 4761 PBB-HVPLS draft-balus- l2vpn-vpls-802.1ah-01.txt VRF back-to back (for L3VPN; option a or d) and similarly Layer2peering (for L2VPN) 100k Mono-AS, Multi-area + multi-instance IGP or ≠ IGPs Multi-AS Not feasible due to the number of LSPs (1) As above (2) : MS-PW; HVPLS VRF back-to back; Layer2peering

All Rights Reserved © Alcatel-Lucent | Session AII.1 | April 2008 Overview of IETF solutions' families If we assume that Max number of LSP = few 10k => justification of the non-feasibility In addition in case of 100k PEs, "flat VPN" solutions that were proposed for the 10k case are applicable to some VPN segments MP2P TE-LSP still under study at IETF (Juniper's) Hierarchical LDP: not proposed yet at the IETF RFC 4206: several TE-LSPs from PE to PE imbedded/nested into a single and smaller TE-LSP PBB-VPLS (VSI Scaling): using PBB in HVPLS enables to hide MAC space from PEs in core (alleviates the amount of VSIs by using N:1 multiplexing)