Locator/ID Separation Protocol (LISP) Architecture & Protocols LISP Team: Vince Fuller, Darrel Lewis, Eliot Lear, Scott Brim, Dave Oran, Elizabeth McGee, Dino Farinacci, and David Meyer Workshop III: Beyond Internet MRA: Networks of Networks Institute for Pure and Applied Mathematics Nov 3-7, 2008

LISP Arch & ProtocolsIPAM MRAWS3Slide 2 Agenda Problem Statement Locator/ID Separation (and why…) What is LISP? LISP Control Plane - LISP+ALT How LISP sites talk to legacy sites Other Uses of LISP Prototype and Pilot Network

LISP Arch & ProtocolsIPAM MRAWS3Slide 3 Provider A /8 Provider B /8 R1R2 BGP End Site Benefit (1)Easier Transition to IPv6 (2)Change provider without address change (3)Active-Active BGP-free Multihoming (4)Data Center Load Spreading Lower OpEx for Sites and Providers (1)Improve site multi-homing (2)Improve site & provider traffic engineering (3) Reduce size of core routing tables (4) IPv4 Address Conservation? Problem Statement Site with PI Addresses

LISP Arch & ProtocolsIPAM MRAWS3Slide 4 Scaling Internet Routing State

LISP Arch & ProtocolsIPAM MRAWS3Slide 5 Why Separate Location from ID? Level of Indirection allows us to: –Keep either ID or Location fixed while changing the other Basically: Routing Locators need to aggregate topologically, while IDs are usually assigned along administrative boundaries  hard to do with one number space –Create separate namespaces which can have different allocation properties By keeping IDs fixed –Assign fixed addresses that never change to hosts and routers at a site You can change Locators –Now the sites can change providers –Now the hosts can move

LISP Arch & ProtocolsIPAM MRAWS3Slide 6 Separating (or adding) an Address Changing the semantics of the IP address LocatorID 2001:0102:0304:0506:1111:2222:3333:4444IPv6: IPv4: Locator ID ID & Location If PI, get new locator If PA, get new ID

LISP Arch & ProtocolsIPAM MRAWS3Slide 7 Provider A /8 Provider B /8 S Multi-Level Addressing EIDs are inside of sites RLOCs used in the core R2R1

LISP Arch & ProtocolsIPAM MRAWS3Slide 8 Map-n-Encap vs Address-Rewrite Host Stack: supplies IDs LISP Router: supplies RLOCs by adding new header Map-n-EncapAddress-Rewrite Host Stack: supplies IDs Router: rewrites RLOCs from existing address GSE

LISP Arch & ProtocolsIPAM MRAWS3Slide 9 So What is LISP?

LISP Arch & ProtocolsIPAM MRAWS3Slide 10 What is LISP? Locator/ID Separation Protocol –Network-based solution –No changes to hosts whatsoever –No new addressing changes to site devices –Very few configuration file changes –Imperative to be incrementally deployable –Address family agnostic

New Network Elements Ingress Tunnel Router (ITR) –Finds EID to RLOC mapping This is the map part of map-and-encap –Encapsulates to Locators at source site This is the encap part of map-and-encap Egress Tunnel Router (ETR) –Authoritative for its EID to RLOC mapping –Decapsulates at destination site LISP Arch & ProtocolsSlide 11IPAM MRAWS3

LISP Arch & ProtocolsIPAM MRAWS3Slide 12 Packet Forwarding Provider A /8 Provider B /8 S ITR D ETR Provider Y /8 Provider X /8 S1 S2 D1 D2 PI EID-prefix /8 PI EID-prefix /8 DNS entry: D.abc.com A EID-prefix: /8 Locator-set: , priority: 1, weight: 50 (D1) , priority: 1, weight: 50 (D2) Mapping Entry > > Legend: EIDs -> Green Locators -> Red > > > Policy controlled by destination site

LISP Arch & ProtocolsIPAM MRAWS3Slide 13 You need a “map” before you can “encap” We have designed several mapping database protocols –CONS, NERD, EMACS, ALT –Tradeoff push versus pull benefit/cost –Needs to be scalable to entries ALT has the most promise –We are deploying ALT Mapping Database Designs

LISP Arch & ProtocolsIPAM MRAWS3Slide 14 What is LISP+ALT? EID namespace is used at the site RLOC namespace is used in the Internet core Mappings need to be authoritative and reside at site ETRs Advertise EID-prefixes in BGP on an alternate topology of GRE tunnels ITRs get mappings by routing Map-Requests on ALT topology ETRs respond with Map-Replies

LISP Arch & ProtocolsIPAM MRAWS3Slide 15 Legend: EIDs -> Green Locators -> Red GRE Tunnel Low Opex Physical link Data Packet Map-Request Map-Reply ETR ITR EID-prefix /24 ITR EID-prefix /24 ALT EID-prefix / > > EID-prefix / > > > ALT-rtr How LISP+ALT Works ? > > ? > > ? < /24 < /24 < /16 ?

Interworking Model We’ve built and deployed the interworking mechanisms described in draft-lewis-lisp-interworking-01.txt LISP Translation –“LISP NAT” – Proxy Tunnel Router (PTR) –Advertises coarsely aggregated EID-prefix(es) into the DFZ Attracts traffic for those prefixes –Behaves like an ITR for that traffic tr0.partan.com is a v4 PTR titanium-dmm-alt-only.lisp.uoregon.edu is a v6 PTR uses the v6 PTR uses the v4 PTR LISP Arch & ProtocolsIPAM MRAWS3Slide 16

LISP Arch & ProtocolsIPAM MRAWS3Slide 17 Other Uses for LISP SLBs in Data Centers –ETRs directly connected to servers –ITRs at Data Center edge A/V Mobile Truck Roll –Avoid renumber at each event BGP-free Core –Intra-AS avoiding storing external routes –RLOCs are PE routers Building topological hierarchy with flat addressing –MAC addressing in L2 networks MAC address mobility for “extended subnets” In an environment of shortage address supply

LISP Arch & ProtocolsIPAM MRAWS3Slide 18 Prototype and Pilot Prototype has been running for a 1.5 years –NX-OS on Titaniums –IOS is under-way –Considering XR and/or CRS blade implementation Alpha has been running for 1 year –Map-Request/Reply, ALT, & Interworking External pilot is underway –Dual-stack ALT –Underlying IPv4 and IPv6 transport –Geographical (registry-based) EID addressing –Interworking IPv4 with translation and PTRs –Interworking IPv6 with PTRs –Low-OpEx xTRs underway

LISP Arch & ProtocolsIPAM MRAWS3Slide 19

LISP in one Slide Today’s Internet - Data Plane LISP-ALT Control Plane LISP Site Non-LISP Site LISP Site GRE Tunnels Physical Links CE LISP Routers LISP Routers RLOCs EIDs EIDs assigned by Internet Registries RLOCs assigned by Service Providers Configure EID -> RLOCs database mappings for local site Stores EID -> RLOCs cache mappings for remote sites Benefits: Improved low-opex multihoming Site based policy and reachability No changes to core routers No changes to site routers No DNS changes No site addressing changes Works with PI or PA prefixes Supports 44-over-6 and 66-over-4 Sites authoritative for their mappings Interworks with non-LISP sites using translation or PTRs Costs: Mapping system required New Software in CE routers New LISP-ALT infrastructure Legend: EIDs (End Site IDs) in green RLOCs (Routing Locators) in red CE: Customer Premise Edge Router ALT: Alternative LISP Topology OH: Outer header, CE to CE IH: Inner header, host to host “Separating ID and Location from an IP address through a level of indirection” CE Advertises EID-prefixes to find mappings CE Advertises RLOCs to maintain aggregation and provide reachability to sites RLOCs EIDs Data Packet Payload OHIHHost Data Tue Nov 4 18:33:30 PST 2008

LISP Arch & ProtocolsIPAM MRAWS3Slide 21 LISP Internet Drafts draft-farinacci-lisp-09.txt draft-fuller-lisp-alt-03.txt draft-lewis-lisp-interworking-01.txt draft-farinacci-lisp-multicast-00.txt draft-meyer-lisp-eid-block-01.txt draft-mathy-lisp-dht-00.txt draft-iannone-openlisp-implementation-01.txt draft-brim-lisp-analysis-00.txt draft-meyer-lisp-cons-04.txt draft-lear-lisp-nerd-04.txt draft-curran-lisp-emacs-00.txt

LISP Arch & ProtocolsIPAM MRAWS3Slide 22 References Public mailing list: Go to a LISP site now: