Six/One Router Six/One Router A Scalable and Backwards-Compatible - - PowerPoint PPT Presentation

Six/One Router Six/One Router

A Scalable and Backwards-Compatible Solution

for Provider-Independent Addressing

Christian Vogt, Ericsson

MobiArch workshop, Seattle, August 22, 2008 number of number of r routing ta

• uting table entries

ble entries

Geoff Huston: CIDR Report www.cidr-report.org

300 K 250 K 200 K 150 K 100 K 50 K 1992 1996 2000 2004 2008 1989

1

edge network edge network edge network edge network edge network

IP address 1234:5d:cff:fe22:57c1 prefix = provider

Towards More Scalable and Flexible Routing

• core: flexible, but not scalable
• global routing table at every

provider

• track route changes Internet-wide
• edge: scalable, but inflexible
• provider-allocated addresses
• renumbering on provider change
• multi-homing infeasible
• need routing architecture

that…

• is scalable
• avoids renumbering
• supports multi-homing

provider provider

edge network

host

provider

core

edge

2

edge network edge network edge network edge network edge network edge network

IP address 1234:5d:cff:fe22:57c1 prefix = provider IP address 1234:3ae:1b8:f5ff:fefd prefix = provider

Towards More Scalable and Flexible Routing

• core: flexible, but not scalable
• global routing table at every

provider

• track route changes Internet-wide
• edge: scalable, but inflexible
• provider-allocated addresses
• renumbering on provider change
• multi-homing infeasible
• need routing architecture

that…

• is scalable
• avoids renumbering
• supports multi-homing

provider provider

edge network

host

provider

core

edge

3

edge network edge network edge network edge network edge network edge network edge network

IP address 1234:5d:cff:fe22:57c1 prefix = provider IP address 1234:3ae:1b8:f5ff:fefd prefix = provider IP address 1234:5d:cff:fe22:57c1 1234:3ae:1b8:f5ff:fefd prefix = provider

Towards More Scalable and Flexible Routing

• core: flexible, but not scalable
• global routing table at every

provider

• track route changes Internet-wide
• edge: scalable, but inflexible
• provider-allocated addresses
• renumbering on provider change
• multi-homing infeasible
• need routing architecture

that…

• is scalable
• avoids renumbering
• supports multi-homing

provider provider

edge network

host

provider

core

edge

4

provider- independent edge addresses

Address Indirection

• decouples addressing at edge from Internet core
• global mapping system for remote edge addresses

provider provider

receiving edge network

reverse mapping provider-allocated transit addresses in core forward mapping

sending edge network indirection router

5

provider- independent edge addresses

Address Indirection

• decouples addressing at edge from Internet core
• global mapping system for remote edge addresses

provider provider

receiving edge network

reverse mapping

e e ➙t t

mapping system provider-allocated transit addresses in core forward mapping

sending edge network indirection router

6

provider- independent edge addresses

legacy edge network

backwards compatibility

Address Indirection

• decouples addressing at edge from Internet core
• global mapping system for remote edge addresses

provider provider

receiving edge network

reverse mapping

e e ➙t t

mapping system provider-allocated transit addresses in core forward mapping

sending edge network indirection router

7

indirection router legacy edge network

backwards compatibility

Address Indirection with Tunneling

• increased bandwidth consumption
• prolonged path
• no incentives model for proxies

provider provider decap

e e ➙t t

mapping system encap

receiving edge network sending edge network

provider- independent edge addresses provider-allocated transit addresses in core

proxy provider

Contribution of Six/One Router address indirection enabling…

• minimum extra packet overhead
• direct-path routing
• autonomous deployment

idea: one-to-one address rewriting

9

assigns

• wns

provider

Network Setup and Addressing

• one-to-one mapping between edge/transit addresses

edge network Six/One router rewrites host has edge address

provider-independent edge addresses provider-allocated transit addresses

… and transit address

10

Address Rewriting

• provider-independence by rewriting local addresses
• transparency through rewriting remote addresses

edge network edge network

from to from to from to from to from to from to host has edge address edge address rewrite reverse rewrite provider provider correspondent host has

11

Backwards Compatibility

• natural fall-back to unilateral rewriting
• loss of transparency requires NAT traversal support

from to from to from to from to rewrite no inverse rewrite

edge network edge network

host has edge address correspondent host has edge address provider provider

12

Multi-Homing Support

edge network

host has edge address provider

edge network

provider provider

edge addresses and host has

correspondent host

13

Multi-Homing Support

• redirect via packet extension with original edge address

from to from to

extension (

) from to from

extension (

) to

edge network

host provider

edge network

provider provider from to from to has edge address correspondent host

Conclusions address indirection enabling…

• minimum extra packet overhead
• direct-path routing
• autonomous deployment’

…possible with one-to-one address rewriting

• transparent with bilateral rewriting
• backwards compatible with unilateral rewriting

future work: implementation and experimentation