Locator/ID Separation Protocol (LISP) Architecture & Protocols LISP Team: Vince Fuller, Darrel...

Locator/ID Separation Protocol (LISP)Locator/ID Separation Protocol (LISP)

Architecture & ProtocolsArchitecture & 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 NetworksInstitute for Pure and Applied Mathematics

Nov 3-7, 2008

LISP Arch & LISP Arch & ProtocolsProtocols

IPAM MRAWS3IPAM MRAWS3 Slide Slide 22

AgendaAgenda

• 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



Provider A10.0.0.0/8

Provider B11.0.0.0/8

R1 R2

BGPEnd 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 StatementProblem Statement

Site withPI Addresses



Scaling Internet Routing StateScaling Internet Routing State



Why Separate Location from ID?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



Separating (or adding) an AddressSeparating (or adding) an Address

Changing the semantics of the IP address

Locator ID

2001:0102:0304:0506:1111:2222:3333:4444IPv6:

209.131.36.158IPv4:

Locator

.10.0.0.1

ID

ID & Location

ID & Location

If PI, get new locatorIf PA, get new ID





S

Multi-Level Addressing

EIDs are inside of sites

RLOCs used in the core

R2R1



Map-n-Encap vs Address-Map-n-Encap vs Address-RewriteRewrite

Host Stack:supplies IDs

LISP

Router:

supplies RLOCs

by adding new

header

Map-n-Encap Address-Rewrite

Host Stack:supplies IDs

Router:

rewrites RLOCs

from existing

address

GSE



So What is LISP?So What is LISP?



What is LISP?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


Slide Slide 1111IPAM MRAWS3IPAM MRAWS3



Packet ForwardingPacket Forwarding



S

ITR

DITR

ETR

ETR

Provider Y13.0.0.0/8

Provider X12.0.0.0/8S1

S2

D1

D2

PI EID-prefix 1.0.0.0/8 PI EID-prefix 2.0.0.0/8

DNS entry:D.abc.com A 2.0.0.2

EID-prefix: 2.0.0.0/8

Locator-set:

12.0.0.2, priority: 1, weight: 50 (D1)

13.0.0.2, priority: 1, weight: 50 (D2)

Mapping

Entry

1.0.0.1 -> 2.0.0.2

1.0.0.1 -> 2.0.0.2

11.0.0.1 -> 12.0.0.2

Legend:

EIDs -> Green

Locators -> Red

1.0.0.1 -> 2.0.0.2

11.0.0.1 -> 12.0.0.2

1.0.0.1 -> 2.0.0.2

12.0.0.2

13.0.0.2

10.0.0.1

11.0.0.1

Policy controlledby destination site



• 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 1010 entries

• ALT has the most promise– We are deploying ALT

Mapping Database Mapping Database DesignsDesigns



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



Legend:

EIDs -> Green

Locators -> Red

GRE Tunnel

Low Opex

Physical link

Data Packet

Map-Request

Map-Reply

ETR

ETR

ETR

ITR

EID-prefix

240.1.2.0/24

ITR

EID-prefix

240.1.1.0/24

ALT EID-prefix

240.2.1.0/24

240.0.0.1 -> 240.1.1.1

1.1.1

.1

2.2.2.2

3.3.3.3

240.0.0.1 -> 240.1.1.1EID-prefix

240.0.0.0/24

1.1.1.1 -> 11.0.0.1240.0.0.1 -> 240.1.1.1

11.0.0.1 -> 1.1.1.1

ALT-rtr

ALT-rtr

ALT-rtr

ALT-rtr

ALT-rtr

ALT-rtr

12.0.0.1

11.0.0.1

How LISP+ALT Works

?

240.0.0.1 -> 240.1.1.1

11.0.0.1 -> 240.1.1.1

? 240.0.0.1 -> 240.1.1.1

11.0.0.1 -> 240.1.1.1

?<- 240.1.1.0/24

<- 240.1.2.0/24

< - 240.1.0.0/16

?

Interworking ModelInterworking Model• We’ve built and deployed the interworking mechanisms

described in draft-lewis-lisp-interworking-01.txt

• LISP Translation– “LISP NAT”– http://www.translate.lisp4.net

• 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• http://www.lisp6.net uses the v6 PTR• http://www.lisp4.net uses the v4 PTR





Other Uses for LISPOther 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



Prototype and PilotPrototype 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 in one SlideLISP in one Slide

Today’s Internet - Data Plane

LISP-ALT Control Plane

LISP Site

Non-LISP Site

LISP SiteGRE TunnelsGRE Tunnels

Physical Links

Phys

ical

Lin

ks

CE

LISP Routers

LISP Routers

RLOCsRLOCs

RLOCs

RLOCs

EIDsEIDs

EIDs assigned by Internet Registries

RLOCs assigned by Service Providers

Configure EID -> RLOCsdatabase mappings

for local site

Stores EID -> RLOCscache mappingsfor 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 greenRLOCs (Routing Locators) in redCE: Customer Premise Edge RouterALT: Alternative LISP TopologyOH: Outer header, CE to CEIH: 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 aggregationand provide reachability to sites

RLOCs EIDs

Data Packet

Payload

OH IH Host Data

Tue Nov 4 18:33:30 PST 2008



LISP Internet DraftsLISP Internet Draftsdraft-farinacci-lisp-09.txtdraft-fuller-lisp-alt-03.txtdraft-lewis-lisp-interworking-01.txtdraft-farinacci-lisp-multicast-00.txtdraft-meyer-lisp-eid-block-01.txt

draft-mathy-lisp-dht-00.txtdraft-iannone-openlisp-implementation-01.txtdraft-brim-lisp-analysis-00.txt

draft-meyer-lisp-cons-04.txtdraft-lear-lisp-nerd-04.txtdraft-curran-lisp-emacs-00.txt



ReferencesReferences

• Public mailing list:[email protected]

• Go to a LISP site now:http://www.lisp4.net

http://www.lisp6.net

Locator/ID Separation Protocol (LISP) Architecture & Protocols LISP Team: Vince Fuller, Darrel...

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