Download - LISP BOF Update

LISP BOF UpdateLISP BOF Updatedraft-farinacci-lisp-08.txt

Dino Farinacci, Dave Meyer, Vince Fuller, Darrel Lewis,Scott Brim, Dave Oran

IETF Dublin - July 2008

LISP BOF UpdateLISP BOF Update IETF Dublin - July 2008IETF Dublin - July 2008 Slide Slide 22

AgendaAgenda

• Overview of LISP• Changing Mapping Database Entries• Support for Mixed Locators• Spec changes between -06 to -08• Open Issues


LISP Internet DraftsLISP Internet Draftsdraft-farinacci-lisp-08.txtdraft-fuller-lisp-alt-02.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


LISP Problem StatementLISP Problem Statement• Improve site multi-homing

– Allow site control ingress traffic paths– Avoid renumbering by providing for portable addresses– Do it with lower OpEx

• Improve Traffic Engineering for ISPs– Use level of indirection rather than more specific injection

• Reduce core routers routing table size• Aid in IPv4 to IPv6 transition• Provide Server Load Balancing in Data Center• Some form of mobility


LISP ConceptuallyLISP Conceptually• IPv4 and IPv6 addresses have overloaded

semantics • LISP separates Location from ID• Introduces 2 address spaces:

– Endpoint IDs (EIDs)– Routing Locators (RLOCs)

• Use 32-bit EIDs for IPv4 from registry allocation• Use 128-bit EIDs for IPv6 from registry allocation• Use topological addresses for Locators from ISP

address block allocations


Multi-Level Addressing

Provider A10.0.0.0/8

Provider B11.0.0.0/8

S EIDs are inside of sites

RLOCs used in the core

R2R1

1.0.0.0/8

10.0

.0.1 1

1.0

.0.1

Mapping Database Entry:

1.0.0.0/8 -> (10.0.0.1, 11.0.0.1)


LISP is Map-n-EncapLISP is Map-n-Encap

Host Stack:supplies EIDs

LISP Router:

supplies RLOCs

by adding new

header

EID-prefix: 2.0.0.0/8

Locator-set (RLOCs):

12.0.0.2, priority: 1, weight: 50


Mapping Entry:


LISP Solution SpaceLISP Solution Space

• 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


Unicast Packet ForwardingUnicast Packet 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


Locator-set:

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


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


Locator ReachabilityLocator Reachability



S

ITR

D

ITR

ETR

ETR



S2

D1

D2

PI EID-prefix 2.0.0.0/8


Locator-set:



Mapping

EntryLegend:

EIDs -> Green

Locators -> Red

12.0.0.2

13.0.0.2

10.0.0.1

11.0.0.1

-> ordinal 0

-> ordinal 1

loc-reach-bits:0x0000 0003

S

S

D

D

0003

0003 D1 D2

D1 D2

7654 3210b’xxxx xxxx’

0002

D2 D2

D2 D2

X X X


Changing Mapping EntriesChanging Mapping Entries

• A “change” is defined to be:– Adding a locator to a locator-set– Changing an existing locator’s priority or weight (for

either unicast or multicast)– Removing a locator from a locator-set

• Adding entries is simple– Append to the end, new loc-reach-bit allocated and set– Old cachers ignore loc-reach-bit set for non-existent

locator– New cachers use new locator-set and all loc-reach-bits


Changing Mapping EntriesChanging Mapping Entries

• Removing a locator is done by:– Set loc-reach-bit to 0– “Zero-fill” address in slot, set priority 255– Old cachers have non-zero slot but don’t

use locator since loc-reach-bit 0– New cachers see empty 255 slot and don’t

use

• Changing priority or weights– Use Clock Sweep or SMRs


Changing Mapping EntriesChanging Mapping EntriesEID-prefix: 153.16.1.0/24, loc-reach-bits: 0x000f, locator-set:





Changed providers: 2.0.0.2 disconnect and 5.0.0.5 connects

Over time compaction may be requiredto get loc-reach-bits back!

EID-prefix: 153.16.1.0/24, loc-reach-bits: 0x001d, locator-set:






delete

add


Locator-Set Compaction Locator-Set Compaction ChangesChanges

• Operational Mechanism– Clock Sweep

• Protocol Mechanism– Solicit Map-Requests (SMRs)


Clock SweepClock Sweep

time

Start thechange process

24 hours

Send Map-Replies with old mapping with TTL = 1 hour

TTL = 24 cacherstime out,

TTL = 1 cachers havebeen timing out

each hour

1 hour 1 minute

Change processends

Send Map-Replies with old mapping with TTL = 1 minute

(not to scale)

TTL = 1 hour cacherstime out,

TTL = 1 minute cachers havebeen timing out

each minute

Send Map-Replies with new mapping with TTL = 24 hours


Solicit Map-Requests (SMRs)Solicit Map-Requests (SMRs)• Used when a site needs compaction• Sites solicit Map-Requests from active sites

– SMR-bit is in encapsulated LISP header– ITRs rate limit to control the number and rate of Map-Requests

they want to receive• Remote ITRs rate-limit Map-Requests until they get a Map-

Reply with the new database mapping entry• Nonce from SMR copied to Map-Request copied to Map-Reply• Map-Request can be sent either on ALT or underlying

network• Local ITR keeps track of which site has new versus old

mappings for appropriate loc-reach-bit setting• No map versioning required

– Recommendation is to have only one outstanding change


Mixed LocatorsMixed Locators

• What are mixed locators?

dr22# sh ip lisp map-cacheLISP IP Mapping Cache for VRF "default" - 1 entries240.23.0.0/24, uptime: 00:00:14, state: complete, last modified: 00:00:14 1.22.23.23, uptime: 00:00:14, state: up, priority/weight: 1/50 11.22.23.23, uptime: 00:00:14, state: up, priority/weight: 1/50

dr22# sh ipv6 lisp map-cacheLISP IPv6 Mapping Cache for VRF "default" - 1 entries0240:0023::/32, uptime: 00:22:00, state: complete, last modified: 00:22:00 dfdf:2223::0023, uptime: 00:22:00, state: up, priority/weight: 1/33 1.22.23.23, uptime: 00:22:00, state: up, priority/weight: 1/33 11.22.23.23, uptime: 00:22:00, state: up, priority/weight: 1/33

Mixed locator-set


Mixed LocatorsMixed Locators• LISP-ALT needs to be dual-stack• Data Probes and Map-Requests are

homogenous– EID needs to be in destination address

• Map-Reply is sent on the underlying network– Therefore underlying has to be dual-stack– But IPv6 is not ubiquitous so we need IPv4

Map-Replies for IPv6 Data Probes or Map-Requests


Mixed Locators - Some Mixed Locators - Some CautionsCautions

• Locator Reachability tells you that xTR is up– Doesn’t tell you what the AF path is from you to the ETR

• Hashing considerations– Destination EID hashes to AF RLOC– Source RLOC must be same AF

• Setting priorities for a mixed locator-set is difficult– Because you don’t know AF path for requesting source

site– Better to have “crossed sets”

• IPv4 EIDs -> all IPv6 RLOCs (China and Japan deployments)• IPv6 EIDs -> all IPv4 RLOCs (US deployments)


Mixed Locators are UsefulMixed Locators are Useful



S

ITR

DITR

ETR

ETR



S2

D1

D2

12.0.0.2

13.0.0.2

10.0.0.1

11.0.0.1

IPv4 Internet

IPv6-onlyIPv6-only

Legend:

EIDs -> Green

Locators -> Red


Mixed Locators are UsefulMixed Locators are Useful



SITR

DITR

ETR

ETR

Provider Y13.0.0.0/813::/16


S2

D1

D2

12.0.0.2

13.0.0.2

10.0.0.1

11.0.0.1

Partly Dual-Stack Internet

IPv6-only

Dual-stack

13::.21

13.0.0.22

S

D

Dual-stack

E2E1

IPv4IPv6 IPv6

IPv4/IPv6IPv4/IPv6

IPv4/IPv6Legend:

EIDs -> Green

Locators -> Red


Spec Diffs between -06 to -08Spec Diffs between -06 to -08

• Lots of clarification text from many reviewers• Clearly specify only 2 LISP headers can be

prepended– First one for Loc/ID split by CPE router– Second one for TE by ISP router

• Add SMR-bit to data header and Map-Request– Steal a loc-reach-bit

• Specify how to select a source UDP port number


• Added mpriority and mweight– So locator selection can be different for unicast or

multicast flows

• Updated section on LISP-Multicast to summarize details in draft-farinacci-lisp-multicast-00.txt

• When ITR receives ICMP unreachable– It may originate one to the source host inside of its site

• Add section on locator hashing for equal-priority locators

• Add sections for Clock Sweep and SMRs• Updated milestone section

Spec Diffs between -06 to -08Spec Diffs between -06 to -08


Rough Set of MilestonesRough Set of Milestones 1. This draft will be the draft for interoperable implementations to code against. Interoperable implementations will be ready summer of 2008.

2. Continue pilot deployment summer of 2008 using LISP-ALT as the database mapping mechanism.

3. Continue prototyping other database lookup schemes, be it DNS, DHTs, CONS, ALT, NERD, or other mechanisms.

4. Implement the LISP Multicast draft [MLISP].

5. Research more on how policy affects what gets returned in a Map- Reply from an ETR.

6. Continue to experiment with mixed locator-sets to understand how LISP can help the IPv4 to IPv6 transition.


AccomplishmentsAccomplishments 1. A unit- and system-tested software switching implementation has been completed on cisco NX-OS for this draft for both IPv4 and IPv6 EIDs using a mixed locator-set of IPv4 and IPv6 locators.

2. A unit- and system-tested software switching implementation on cisco NX-OS has been completed for draft for [ALT].

3. A unit- and system-tested software switching implementation on cisco NX-OS has been completed for draft [INTERWORK]. Support for IPv4 translation is provided and PTR support for IPv4 and IPv6 is provided.

4. The cisco NX-OS implementation supports an experimental mechanism for slow mobility.

5. Dave Meyer, Vince Fuller, Darrel Lewis, Greg Shepherd, and Andrew Partan continue to test all the features described above on a dual-stack infrastructure.

6. Darrel Lewis and Dave Meyer have deployed both LISP translation and LISP PTR support in the pilot network. Point your browser to http://www.lisp4.net to see translation happening in action so your non-LISP site can access a web server in a LISP site.

7. Soon http://www.lisp6.net will work where your IPv6 LISP site can talk to a IPv6 web server in a LISP site by using mixed addres- family based locators.

8. An public domain implementation of LISP is underway. See [OPENLISP] for details.

9. A cisco IOS implementation is underway which currently supports IPv4 encapsulation and decapsulation features.


Open IssuesOpen Issues• Experiment with more-specific mappings and policy-based

Map-Reply priority changing • ISP resident TE-xTR functionality with another “multi-level

LISP” hierarchy• Firm up details on LISP-Multicast• LISP can do some form of mobility

– More specific state only at edges in xTRs– Can we extend it for secure and graceful handoff

• Continue prototyping ideas and deploying on pilot network• Interoperability testing of NX-OS, IOS, and OpenLISP


[email protected]

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