LISP Deployment Scenarios Darrel Lewis and Margaret Wasserman IETF 76, Hiroshima, Japan

Slide 2 Agenda Introduction : Deployment scenario implication for the LISP Specification Survey of LISP Network Elements –XTRs –Map Servers –Map Resolvers –Proxy ITRs –Proxy ETRs Gauge level of interest in developing an informational draft

Slide 3 Introduction The goal of this presentation is to inform the community about how we are expecting LISP to be deployed –Help to bound the discussion within practical scenarios Covers cases we expect to be most common, not all possibilities are covered For each element we’ll discuss possible deployment scenarios –And hopefully the tradeoffs For each element we’ll discuss the impact of deployment scenarios on the spec

Slide 4 LISP xTRs as the CE R1R2 BGP Provider A /8 Provider B /8 Provider Independent (PI) /8 Internet

Slide 5 LISP xTRs xTRs at customer premise (CE) –Advantages Site control of egress TE Site control of ingress TE Encapsulate last, Decapsulate first –Disadvantages None? –Spec implications LISP needs to work on typical CPE hardware –Higher-end routers for mid-to-large enterprise –Lower-end routers/CPE devices for SOHO

Slide 6 LISP xTRs (cont) ITR and ETR split into different devices for a site –Advantages Best path vs. shortest path –Disadvantages Additional mechanism (such as OSPF) needed for ITRs to detect ETR liveness Site must carry full routes –Spec implications Need for functional separation of ITR/ETR

Slide 7 Split ITR/ETR Site Provider A /8 Provider B /8 S ITR 4G Provider /8 S1 S2 LISP EID-prefix / Encapsulate -> 3G Provider /8 ETR S3 S4 iBGP <- Decapsulate

Slide 8 LISP xTRs xTRs at the Provider Edge (PE) –Advantages Site doesn’t have to upgrade CE Multi-homing to a single SP might work –Degenerate of the VPN case local NAT in –Disadvantages Site loses control of egress TE Locator liveness is problematic –Implications LISP would need to work on typical PE hardware

Slide 9 LISP xTRs (cont) xTRs for Inter-Service Provider TE –Advantages Separate mapping database shared between service providers Bilateral agreements allow traffic engineering across multiple MPLS ASes –Disadvantages Extra header, add’l looked, database maintenance –Implications Requires support for two levels of LISP headers

Slide 10 Map Server Authenticated Map Register messages are sent to Map Servers by ETRs Map Server(s) will probably be provided by an EID registrar Redundant servers are desirable Impacts: –Need mechanism to configure EID prefix(es), keys and map server address(es) on ETRs

Slide 11 Map Resolver Map Requests are sent to Map Resolvers by ITRs Map resolvers will probably be provided by Internet Service Providers Impacts: –Need DHCP option or other mechanism to configure map resolver address(es) on ITRs

Slide 12 Proxy-ITRs R-prefix /16 R-prefix /16 R-prefix / / /12 Infrastructure Solution Legend: LISP Sites -> Green (and EIDs) non-LISP Sites -> Red (and RLOCs) xTR NR-prefix /16 NR-prefix /16 NR-prefix / P-ITR BGP Advertise: /8 P-ITR BGP Advertise: /8 P-ITR BGP Advertise: / > (1) > (3) Encapsulate > > (2)

Slide 13 LISP Proxy-ITRs Advantages –Allow connectivity between LISP nodes and non- LISP nodes –Early Adopter LISP sites see benefits of LISP Disadvantages –Non-LISP traffic may take suboptimal route through Proxy ITR (compared to LISP-NAT) Implications –Defined in Interworking specification

Slide 14 Proxy-ETRs R-prefix /16 R-prefix /16 R-prefix / / /12 Legend: LISP Sites -> Green (and EIDs) non-LISP Sites -> Red (and RLOCs) xTR NR-prefix /16 NR-prefix /16 NR-prefix / P-ETR < (2) Encapsulate < < (1) P-ITR BGP Advertise: /8 P-ITR BGP Advertise: / Encapsulate

Slide 15 LISP Proxy-ETRs Advantages –Allows LISP nodes in sites with URPF restrictions to communicate with non-LISP nodes –Allows LISP in sites without natvie IPv6 support to communication with LISP nodes that have only v6 RLOCs –Can (should?!) be separate devices from Proxy- ITRs Disadvantages –Packets may take longer path through P-ETR Implications –Defined in Interworking specification

Slide 16 Early Adopter/Experimental xTRs behind a NAT –Advantages: Allows LISP connectivity to/from sites behind a NAT for test network/early deployment –Disadvantages: Somewhat Complex to configure –Implications : Limited NAT traversal needed –1 xTR at global address, static port forwarding for 4341 & 4342 –Dynamic Locator in ETR Database Needed for short term, when LISP is not integrated with provider-supplied CPE

Slide 17 Wrap UP Is further work needed in this area? Should we write an informational draft?