Document No:
GSC16-PLEN-71
Source:
CCSA
Contact:
cuiyong@tsinghua.edu.cn
GSC Session:
PLENARY
Agenda Item:
7.3
4over6 technology for IPv6 transition
Yong CUI
CCSA
(Tsinghua University)
Halifax, 31 Oct – 3 Nov 2011
ICT Accessibility For All
GSC16-PLEN-71
IPv6 Transition Background
•Contradictions in IPv6 transition
•Not enough IPv4 addr.(exhausted on 2011.2.3)
•Lack of IPv6 applications provided by ICP
•Hard to fulfill users’ demands after upgrading
to IPv6
•Key problems in IPv6 transition for ISP
•Meet users’ IPv4 demands
•Provide IPv4 transmission
•Lower the cost of upgrading current network
Halifax, 31 Oct – 3 Nov 2011
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2
Strategic Direction
Dual
stack
Tunneling
IP layer
(Hardware)
GSC16-PLEN-71
Translation
Processing
Layer
ALG
(Software)
•Heterogeneous
State
Stateful/stateless
addressing:
Stateless
Maintenance (Not Scalable)
Private/IPv4/IPv6
(Scalable)
•Difficult to use &
Operation
High
Low
manage
Complexity
•Huge cost to
Routing merge
Separated routing IPv4/IPv6
upgrade &
Routing
(No Scalable)
(Scalable)
maintain
Application
4/6 interE-IP over I-IP
Scenario
connection
Halifax, 31 Oct – 3 Nov 2011
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Transition Challenges
GSC16-PLEN-71
•Current situation
•Slow IPv6 network construction
•Huge cost of upgrading network equipments
•Users’ demands
•Provide full service support
•The same User Experience with IPv4 services
•ISP transition strategy
•Complete the IPv6 network
•IPv6-over-IPv4 doesn’t fit
•IPv4-over-IPv6 works better
Halifax, 31 Oct – 3 Nov 2011
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GSC16-PLEN-71
4over6 Transition Architecture
4over6 Transition Architecture
4over6 mesh
Transparent transmission
in backbone
Extension of BGP
Public 4over6
Lightweight 4over6
Heterogeneous
access network
Heterogeneous
access + addr. sharing
Remote addr. Allocation
managing of IPv6 tunnel
Adaptive port control
protocol
• Solve IPv6 transition problems in backbone and
access network
• Transparently support existed services transiting to
IPv6 network
• Avoid losing IPv4 users
• Access IPv4 resources over IPv6 network
Halifax, 31 Oct – 3 Nov 2011
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5
GSC16-PLEN-71
4over6 Mesh Framework
IETF RFC 5565: Softwire mesh framework
(Standards track RFC)
Extension of MP-BGP
Setup 4over6 peer
IPv4 Network
Provide IPv4/IPv6 access
by IPv6 backbone
Stateless packet
Encap/Decap
4over6
4over6
Auto tunnels:
“1:N”address mapping
IPv4 Network
IPv6 Backbone
4over6
(CERNET 2)
4over6
IPv4 Network
IPv4 Network
IPv6 Network
IPv6 Network
•Scenario:IPv4-over-IPv6/IPv6-over-IPv4
•Multiple tunnel types support
Halifax, 31 Oct – 3 Nov 2011
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6
GSC16-PLEN-71
Critical issues in access network
• Address allocation
– Public IPv4 addr in end system to avoid large scale NAT
– AFBR allocate IPv4 addr(+port) to end system
• State maintenance in AFBR
Public
4over6
– Stateless：46 addr. embedding
– Stateful：IPv4-IPv6 mapping，decouple IPv4/IPv6 addr
• IPv4 addr multiplexing
– Implement stateful/stateless multiplexing
Full use
existing IPv4
stack in end
system
Halifax, 31 Oct – 3 Nov 2011
ISP IPv6
network
4over6 tunnel
IPv4 addr.
allocation
Lightweight
4over6
IPv4
Internet
AFBR
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Public 4over6
GSC16-PLEN-71
• IPv4 address allocation in IPv6 network
– DHCPv4-over-IPv6
• IPv4-over-IPv6 data transmission
– Outbound: encapsulation IPv6 destination addr is
tunnel concentrator (TC) addr
– Inbound: use IPv4-IPv6 mapping to get tunnel initiator
(TI) addr
DHCPv4over-IPv6
Public
IPv4 addr
IPv4 Internet
Local
IPv4
Network
Halifax, 31 Oct – 3 Nov 2011
IPv6 Edge
Network 4over6 TC
4over6 TI
Host/CPE
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Lightweight 4over6
GSC16-PLEN-71
• IPv4 address multiplexing
– Make full use of IPv4 address resources
• Critical tech
– Based on public 4over6
– TC allocates public IPv4 addr + port to TI
– TC need to maintain a lightweit address mapping
(IPv6–IPv4 aadr + port)
No NAT
Public IPv4
addr + port
IPv4 Internet
Local
IPv4
Network
Halifax, 31 Oct – 3 Nov 2011
IPv6 Edge
Network
TC
TI
Host/CPE
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