Softwire wg

Alain Durand, Comcast

David Ward, Cisco

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Wg status

• Charter went to internal & external review• Comments received• Chairs, AD & IESG members started addressing the

comments…• …AD had a baby! (Congratulation!)

• As of this morning, we are approved as a wg by the IESG!– Secretariat still needs to make it formal

Agenda

• Overview of meeting in Paris (Chairs)

• Hub and Spoke Problem Overview (Durand)– Hub and Spoke Illustration (Miyakawa, Palet, Williams)

• Mesh Problem Overview (Ward)– Mesh Illustration (Li)

• Status of draft problem statement (Chairs)

• Next steps (Chairs, all)

Paris Interim Meeting

• We held an interim meeting in Paris on October 11th-12th

– 18 participants, intense discussions, very productive meeting

• Focus on problem statement– draft-durand-softwire-problem-statement-00.txt

edited in rush just before the cut-off date (excuse typos…)

• 2 problems identified, topology driven:– Access network, customer initiated, one exit path [Hubs & Spokes]– Core network, ISP initiated, complex routing topology [Mesh]

• We will look at both problems independently– Hopefully, they will share enough common technology

Hub & Spoke Description

Hubs & Spokes Problem

• Description:– Access network problem, customer initiated, one exit path

• Applicability:– ISPs with Dual Stack core and a number of dual stack Points of

Presence (“Hubs”) where they connect their customers.

• 3 usage cases have been identified:– the networks between the CPE router and the hub supports only one

address family.– the CPE router cannot be easily upgraded to support both address

families, a softwire is created from a node behind the CPE router– Same, but initiated from another router behind the CPE router

Usage Case 1

Dual AF

Single AF

CPE Router Dual AF

Softwire Initiator

SoftwireConcentrato

r

Usage Case 2

Dual AF

CPE Router Single AF

Dual AF HostSoftwire Initiator

SoftwireConcentrato

r

Usage Case 3

Dual AF

CPE Router Single AF

Dual AF RouterSoftwire Initiator

SoftwireConcentrato

r

Hubs & Spokes Assumptions• NAT/PAT (in IPv4) is present

• Not always upgradeable CPE router

• “Stable” IPv6 prefix desired

• Softwires initiated by customer– Customer side: softwire initiator

• May be a host or a router– ISP side: softwire concentrator

• Routing:– default route from softwire initiator to concentrator

• (CPE routers do not generally run a routing protocol, but the softwire solution will work even if it does.)

Hubs & Spokes Properties (1)

• Scaling:– to the millions of softwire customers

• Set-up time (a.k.a. “latency”)– A fraction of the total set-up time of the CPE router

• Multicast– Classic multicast solution run over the softwire

Hubs & Spokes Properties (2)

• Security– Must support secure user authentication

• May be turned off.– Must be able to support payload security when desired outside

of the softwire mechanism

• Operation And Management– Keep alive– Usage accounting– End point failure detection (inner address of the softwire)– Path failure detection (outer address of the softwire)

Hubs & Spokes Encapsulations

• Critical path– IPv6/IPv4– IPv6/UDP/IPv4– IPv4/IPv6

• Other encapsulations to be supported later(e.g. IPv6/IPv6)

Hub & Spoke Illustrations

Slides from Shin, Carl & Jordi

Mesh Description

Mesh Problem

• Description:– Core network problem, ISP initiated, complex routing topology

• Applicability:– ISPs (or large enterprise networks acting as ISP for their internal

resources) establish connectivity to 'islands' of networks of one address family type across a transit core of a differing address family type.

Mesh Diagram

IPv6-only Transit Core

BGP Dual-Stack AFBR

BGP Dual-Stack AFBR

BGP Dual-Stack AFBR

BGP Dual-Stack AFBR

IPv4Access Island

IPv4Access Island

IPv4Access Island

IPv4Access Island

IPv6Access

Network

IPv6Access

Network

AFBR

• To provide reachability across the transit core dual-stack devices are installed that act as "Address Family Boundary Routers”.– Creates a limited dual-stack edge network– Core can be solely one AF and islands don’t require upgrade

• AFBR provide peering across AS or within an AS• Can be used inconjunction w/ route reflectors

Full Mesh Overlay for Many2Many connnectivity

AFBR

AFBR

AFBR

V6 transit

V4 island

V4 island

V4 island

May have different encaps available

Must have solution to allow for negotiation and preference of encap

AFBRMGREIPsec

V6 transitcore AFBR

MGRE,L2TPv3

AFBRL2TPv3MPLS

V4 island

V4 island

V4 island

L2TPv3 MGRE

IPsec

Must support Applications…. L3-VPN using 2547bis

Route Reflector

AFBR

AFBR

V6 transit

V4 island

V4 island

V4 island

AFBR

VPN VPN

VPN

Mesh properties (1)• Scaling

– Number of AFBR related to the number of islands and exit points from islands (x0-x00 islands)

• We know of no cases of x0000++ islands

– Full routing table needs to be supported• Islands can carry x00000 of routes

• Services / Encapsulation– v4/v6 or v6/v4– L2VPN– L3VPN (overlapping address spaces)– Multicast a must in all cases

• Security– No “user” authentication– Authentication for control plane

• may be turned off– Support for IPsec in data plane (outside of softwires)

Mesh properties (2)

• Operation And Management– No need for keepalive– Usage accounting– End point failure detection– Path failure detection– Flexible encapsulation possibilities– Interconnection at L2 or L3– Cannot require full mesh of all AFBRs under all circumstances

Mesh Illustrations

Slides from Pr Li

Problem Statement Draft Status

• Problem statement described in draft-durand-softwire-problem-statement-00.txt

• Comments received on the ML– Typos– Some minor stuff– n engineer that comes up with n+1 design syndrome– 3 issues raised about the Mesh problem:

• Scale– Presented today

• Should this be solved at layer 2 or layer 3– Crystal ball says both (This belongs to the solution space)

• Should the softwires be initiated from the PE or CPE or both?– Crystal ball says most commonly PE (for mesh)

Next Steps

• Mark finish the creation of the wg!– Done, minor nits on charter + secretariat action

• Rev problem statement draft– draft-ietf-softwire-problem-statement-00.txt Nov. 14th– draft-ietf-softwire-problem-statement-01.txt Dec. 1st

• WG Last Call on problem statement draft– Target: Dec. 8th

• Interim meeting on solution space (Jan/Feb 06)– Last was in Europe, Hong Kong?