Transcript LISP and BGP IDR WG, IETF Dublin, July, 2008 Vince Fuller (for the LISP crew)

LISP and BGP
IDR WG, IETF Dublin, July, 2008
Vince Fuller (for the LISP crew)
Agenda
• Motivation for LISP (and ALT)
• How LISP+ALT uses BGP
• A few considerations
IDR WG
IETF Dublin, July, 2008
Slide 2
LISP Internet Drafts
draft-farinacci-lisp-08.txt
draft-fuller-lisp-alt-02.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
IDR WG
IETF Dublin, July, 2008
Slide 3
Separate EID/RLOC topologies
“Addressing can follow topology or topology can follow
addressing – choose one” –Y.R.
•
•
•
•
ID/LOC separation avoids this dilemma
EIDs uses organization/geo hierarchy
RLOCs follow network topology
Reduce global routing state through RLOC
aggregation
• EID prefixes are not generally visible in
global routing system
IDR WG
IETF Dublin, July, 2008
Slide 4
EID vs RLOC assignment
Provider A
10.0.0.0/8
ISP allocates 1 locator address
per physical attachment point
(follows network topology)
R1
Legend:
EIDs -> Green
Locators -> Red
IDR WG
R2
Provider B
11.0.0.0/8
RIR allocates EID-prefixes
(follows org/geo hierarchy)
Site
PI EID-prefix 240.1.0.0/16
IETF Dublin, July, 2008
Slide 5
LISP+ALT: What, How and Why
• Hybrid push/pull approach
– ALT pushes aggregates - find ETRs for EID
– ITR uses LISP to find RLOCs for specific EID
• Hierarchical EID prefix assignment
– Aggregation of EID prefixes
• Tunnel-based overlay network
• BGP used to advertise EIDs on overlay
– Why invent something new? (or use DNS?)
• Option for data-triggered Map-Replies
IDR WG
IETF Dublin, July, 2008
Slide 6
LISP+ALT in action
EID-prefix
240.0.0.0/24
?
ITR
Legend:
?
?
< - 240.1.0.0/16
ALT-rtr
ALT-rtr
ETR
EID-prefix
240.1.1.0/24
ALT-rtr
ALT-rtr
ALT-rtr
EIDs -> Green
240.0.0.1 -> 240.1.1.1
240.0.0.1 -> 240.1.1.1
240.0.0.1 -> 240.1.1.1
ITR
240.0.0.1 -> 240.1.1.1
11.0.0.1 -> 240.1.1.1
11.0.0.1 -> 240.1.1.1
ETR
ALT-rtr
Locators -> Red
GRE Tunnel
LAT
Low Opex
Physical link
Data Packet
Map-Request
Map-Reply
IDR WG
ETR
11.0.0.1 -> 1.1.1.1
?
240.0.0.1 -> 240.1.1.1
1.1.1.1 -> 11.0.0.1
IETF Dublin, July, 2008
Slide 7
Securing the mapping system
• ALT can use existing/proposed BGP
security mechanisms (SBGP, etc.)
• DOS-mitigation using well-known
control plane rate-limiting techniques
• Nonce in LISP protocol exchange
• More needed?
IDR WG
IETF Dublin, July, 2008
Slide 8
Non-BGP traffic engineering
• ALT separates ETR discovery from the
ITR-ETR mapping exchange
– very coarse prefixes globally-advertised
– more-specific info exchanged where needed
• Regional ETRs could return morespecific mappings for simple TE
• Alternative to current practice of
advertising more-specific prefixes
IDR WG
IETF Dublin, July, 2008
Slide 9
Simple BGP configs
• No BGP changes required for LISP+ALT
– None made for pilot deployment
– Though separate AFI/SAFI might be a
good idea for debugging/management
• No need for route-reflectors, etc.
• May use iBGP in some cases
IDR WG
IETF Dublin, July, 2008
Slide 10
Questions/Comments?
Contact us: [email protected]
Information: http://www.lisp4.net
OpenLISP: http://inl.info.ucl.ac.be
Thanks!
IDR WG
IETF Dublin, July, 2008
Slide 11