ietf 80 th problem statement for operational ipv6/ipv4 co-existence 3/31/2011 chongfeng xie...
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IETF 80th
Problem Statement for Operational IPv6/IPv4 Co-existence
3/31/2011
Chongfeng Xie ([email protected])
Qiong Sun ([email protected])
Chongfeng Xie ([email protected])
Qiong Sun ([email protected])
北京研究院 2011
Current Situation ISP: facing the biggest pressure of IPv4 address
shortage ICP: lacking of enough motivation to migrate to IPv6 Manufacture: wondering what to do next…
MANAccess
Network
CPEPC
Mobile device
BRAS/
SR/PDSN
Service Platform
AAA
Network Management System
ICP
2
北京研究院 2011
Network Architecture
The placement of AS (Address Sharing) Router has different impacts: Centralized : reduce cost, easy to manage and traffic LAES,
performance bottleneck Distributed : high cost, hard to manage and traffic LAES, less
performance requirement
AS Router would be suitable for centralized placement
3
Backbone
NetworkMetro
Network
Access
Network
CPEPC
Mobile device
BRAS/
SR/PDSN
Service Platform
AAALog server
LAES
DNS
AS Router
Optional
Placement
AS Router
AS Router
AS Router Address
Sharing Router
北京研究院 2011
Communication Scenarios
IPv6 is a final way to solve address shortage; however, there is not much IPv6 content.
IPv4/IPv6 will co-exist for long period.
Two major scenarios: IPv4IPv4 for most current applications and IPv6IPv4 for P2P applications and future IPv6-only ones.
DS-Lite A+P Stateless NAT64 / dIVI
Stateful NAT64
NAT444+IPv6
IPv4IPv4
IPv6IPv6
IPv4IPv4
IPv6IPv6
IPv4IPv4
IPv6IPv4
IPv6IPv6
IPv6IPv4
IPv6IPv6
IPv4IPv4
IPv6IPv6
北京研究院 2011
End-to-End transparency and Scalability
5
DS-Lite A+P Stateless NAT64/dIVI
Stateful NAT64
NAT444+IPv6
CGN problem Better
Core stateless
Better
Core stateless
CGN problem CGN problem
It is important to keep the simplicity in core network and leave the intelligence to end systems.
It should be scalable, easy for new applications to deploy in operational network.
CGN would bring much complexity to the core of Internet, which includes transport-layer port mapping and ALG.
CGN would also bring a lot of cost for ISPs.
北京研究院 2011
Addressing and Routing
6
DS-Lite A+P Stateless NAT64/dIVI
Stateful NAT64
NAT444+IPv6
Address of the tunnel end to be passed
Changes to address allocation related to the address format, address of the tunnel end to be passed
Some changes to address allocation related to the address format
No specific requiremen
t
Private IPv4 addressing
Existing ISPs who adopt PPPoE/PPPoA need to allocate PD-prefix and WAN-interface address, and CPE would re-allocate IPv6 addresses to end systems.
Address allocation system would setup the corresponding routing entries for a given customer.
ISPs may adopt flexible address rules, no extra requirements on address format and address allocation, etc.
北京研究院 2011
Address usage and consumption
7
DS-Lite A+P Stateless NAT64/dIVI
Stateful NAT64
NAT444+IPv6
Dynamic sharing Static sharing Static sharing Dynamic sharing Dynamic sharing
IPv4/IPv6 transition solutions would need address sharing, including dynamic and static ones.
Nowadays, most applications consume many concurrent sessions,
With address multiplexing, IPv4 address shortage problem could already be largely released.
Static sharing is generally sufficient in the near future
北京研究院 2011
User management and logging requirement
8
User type:
IPv6-only
Add IPv6 feature
Logging:
Session-based
User type:
IPv6-only
Add IPv6 feature
Logging:
No binding table
User type:
IPv6-only
Add IPv6 feature
Logging:
No binding table
User type:
IPv6-only
Add IPv6 feature
Logging:
Session-based
User type:
Dual-stack
Add dual stack feature
Logging:
Session-based
User management system, e.g. AAA , etc., to implement accounting and billing.
Transition period would have multiple types of users, e.g. IPv4-only, IPv6-only, or dual stack, etc.
ISPs and ICPs have the requirements of lawful interception and surveillance.
Session-based logging would bring a great burden to existing software-based logging system.
+IPv6+IPv6
北京研究院 2011
CPE issue
9
DS-Lite A+P Stateless NAT64/dIVI
Stateful NAT64
NAT444+IPv6
Tunneling+IPv6 NAT+ Tunneling
+IPv6
dIVI: NAT+ translation+IPv6
IPv6-feature IPv6+NAT44
CPE is more than a technical issue, but rather a business strategy. And different ISPs have their own situations.
CPEs in routed mode have to be upgraded to support IPv6. And cost is extremely huge due to the large number of customers.
Most IPv6 transition solutions would need to take additional modifications to CPE, apart from native IPv6 support.
ISPs sometimes could not fully control customer’s CPEs.
北京研究院 2011
Summary
There is a set of operational requirements related to complexity and as a result of scalability
Existing solutions for IPv4 address sharing is operationally complex
We need more scalable address sharing mechanism to reduce the state, cost and complexity of core network
There are alternatives that make life a lot easier for operators
北京研究院 2011
Summary
We prefer a solution with Good IPv6 support and be helpful for IPv6
development Better scalability
• Stateless ones without address constraint should be our direction
• Keep state as few as possible in core network, only maintain per-subscriber state entries in core network, and state should be stable.
Flexible addressing• Little modification to existing addressing and routing
system• Define flexible addressing plan for different purpose
北京研究院 2011 12
Thank youThank you