draft-ietf-softwire-stateless-4v6-motivation-04.txt   draft-ietf-softwire-stateless-4v6-motivation-05.txt 
Softwires Working Group M. Boucadair, Ed. Softwires Working Group M. Boucadair, Ed.
Internet-Draft France Telecom Internet-Draft France Telecom
Intended status: Informational S. Matsushima Intended status: Informational S. Matsushima
Expires: March 3, 2013 Softbank Telecom Expires: May 17, 2013 Softbank Telecom
Y. Lee Y. Lee
Comcast Comcast
O. Bonness O. Bonness
Deutsche Telekom Deutsche Telekom
I. Borges I. Borges
Portugal Telecom Portugal Telecom
G. Chen G. Chen
China Mobile China Mobile
August 30, 2012 November 13, 2012
Motivations for Carrier-side Stateless IPv4 over IPv6 Migration Motivations for Carrier-side Stateless IPv4 over IPv6 Migration
Solutions Solutions
draft-ietf-softwire-stateless-4v6-motivation-04 draft-ietf-softwire-stateless-4v6-motivation-05
Abstract Abstract
IPv4 service continuity is one of the most pressing problems that IPv4 service continuity is one of the most pressing problems that
must be resolved by Service Providers during the IPv6 transition must be resolved by Service Providers during the IPv6 transition
period - especially after the exhaustion of the public IPv4 address period - especially after the exhaustion of the public IPv4 address
space. Current standardization effort that addresses IPv4 service space. Current standardization effort that addresses IPv4 service
continuity focuses on stateful mechanisms. This document elaborates continuity focuses on stateful mechanisms. This document elaborates
on the motivations for the need to undertake a companion effort to on the motivations for the need to undertake a companion effort to
specify stateless IPv4 over IPv6 approaches. specify stateless IPv4 over IPv6 approaches.
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on March 3, 2013. This Internet-Draft will expire on May 17, 2013.
Copyright Notice Copyright Notice
Copyright (c) 2012 IETF Trust and the persons identified as the Copyright (c) 2012 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Why Stateless IPv4 over IPv6 Solutions are Needed? . . . . . . 4 3. Why Stateless IPv4 over IPv6 Solutions are Needed? . . . . . . 4
3.1. Network Architecture Simplification . . . . . . . . . . . 5 3.1. Network Architecture Simplification . . . . . . . . . . . 4
3.1.1. Network Dimensioning . . . . . . . . . . . . . . . . . 5 3.1.1. Network Dimensioning . . . . . . . . . . . . . . . . . 4
3.1.2. No Intra-domain Constraint . . . . . . . . . . . . . . 5 3.1.2. No Intra-domain Constraint . . . . . . . . . . . . . . 5
3.1.3. Logging - No Need for Dynamic Binding Notifications . 6 3.1.3. Logging - No Need for Dynamic Binding Notifications . 5
3.1.4. No Additional Protocol for Port Control is Required . 6 3.1.4. No Additional Protocol for Port Control is Required . 5
3.2. Operational Tasks and Network Maintenance Efficiency . . . 6 3.2. Operational Tasks and Network Maintenance Efficiency . . . 6
3.2.1. Preserve Current Practices . . . . . . . . . . . . . . 6 3.2.1. Preserve Current Practices . . . . . . . . . . . . . . 6
3.2.2. Planned Maintenance Operations . . . . . . . . . . . . 7 3.2.2. Planned Maintenance Operations . . . . . . . . . . . . 6
3.2.3. Reliability and Robustness . . . . . . . . . . . . . . 7 3.2.3. Reliability and Robustness . . . . . . . . . . . . . . 6
3.2.4. Support of Multi-Vendor Redundancy . . . . . . . . . . 7 3.2.4. Support of Multi-Vendor Redundancy . . . . . . . . . . 6
3.2.5. Simplification of Qualification Procedures . . . . . . 7 3.2.5. Simplification of Qualification Procedures . . . . . . 7
3.3. Facilitating Service Evolution . . . . . . . . . . . . . . 8 3.3. Facilitating Service Evolution . . . . . . . . . . . . . . 7
3.3.1. Implicit Host Identification . . . . . . . . . . . . . 8 3.3.1. Implicit Host Identification . . . . . . . . . . . . . 7
3.3.2. No Organizational Impact . . . . . . . . . . . . . . . 9 3.3.2. No Organizational Impact . . . . . . . . . . . . . . . 8
3.4. Cost Minimization Opportunities . . . . . . . . . . . . . 9 3.4. Cost Minimization Opportunities . . . . . . . . . . . . . 8
4. Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . 10 4. Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . 9
4.1. Dependency Between IPv4 and IPv6 Address Assignments . . . 10 4.1. Dependency Between IPv4 and IPv6 Address Assignments . . . 10
4.2. IPv4 Port Utilisation Efficiency . . . . . . . . . . . . . 11 4.2. IPv4 Port Utilisation Efficiency . . . . . . . . . . . . . 10
4.3. IPv4 Port Randomization . . . . . . . . . . . . . . . . . 11 4.3. IPv4 Port Randomization . . . . . . . . . . . . . . . . . 11
5. Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . 12 5. Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . 11
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11
7. Security Considerations . . . . . . . . . . . . . . . . . . . 12 7. Security Considerations . . . . . . . . . . . . . . . . . . . 11
8. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 12 8. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 12
9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 13 9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 12
10. Informative References . . . . . . . . . . . . . . . . . . . . 13 10. Informative References . . . . . . . . . . . . . . . . . . . . 12
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 15 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 14
1. Introduction 1. Introduction
When the global IPv4 address space is exhausted, Service Providers When the global IPv4 address space is exhausted, Service Providers
will be left with an address pool that cannot be increased anymore. will be left with an address pool that cannot be increased anymore.
Many services and network scenarios will be impacted by the lack of Many services and network scenarios will be impacted by the lack of
IPv4 public addresses. Providing access to the (still limited) IPv6 IPv4 public addresses. Providing access to the (still limited) IPv6
Internet only won't be sufficient to address the needs of customers, Internet only won't be sufficient to address the needs of customers,
as most of them will continue to access legacy IPv4-only services. as most of them will continue to access legacy IPv4-only services.
Service Providers must guarantee their customers that they can still Service Providers must guarantee their customers that they can still
access IPv4 contents although they will not be provisioned with a access IPv4 contents although they will not be provisioned with a
global IPv4 address anymore. Means to share IPv4 public addresses global IPv4 address anymore. Means to share IPv4 public addresses
are unavoidable [RFC6269]. are unavoidable [RFC6269].
Identifying the most appropriate solution(s) to the IPv4 address Identifying the most appropriate solution(s) to the IPv4 address
exhaustion as well as IPv4 service continuity problems and deploying exhaustion as well as IPv4 service continuity problems and deploying
them in a real network with real customers is a very challenging and them in a real network with real customers is a very challenging and
complex process for all Service Providers. There is nothing like a complex process for all Service Providers. There is no one size fits
"One size fits all" solution or one target architecture that would all solution. Each Service Provider has to take into account its own
work for all situations. Each Service Provider has to take into context (e.g., service infrastructures), policies and marketing
account its own context (e.g., service infrastructures), policies and strategy (a document that informs Service Providers about the impact
marketing strategy (a document that informs Service Providers about of the IPv4 address shortage, and provides some recommendations and
the impact of the IPv4 address shortage, and provides some guidelines, is available at [EURESCOM]).
recommendations and guidelines, is available at [EURESCOM]).
Current standardization effort that is meant to address this IPv4 Current standardization efforts to address the IPv4 service
service continuity issue focuses mainly on stateful mechanisms that continuity issue focuses on stateful mechanisms that share global
sharing of global IPv4 addresses between Customers is based upon the IPv4 addresses between customers with NAT (Network Address
deployment of NAT (Network Address Translation) capabilities in the Translation) capabilities in the network. Because of some caveats of
network. Because of some caveats of such stateful approaches the such stateful approaches, the Service Provider community feels that a
Service Provider community feels that a companion effort is required companion effort is required to specify stateless IPv4 over IPv6
to specify stateless IPv4 over IPv6 approaches. Note that the approaches. In the context of address sharing, states should be
stateless solution elaborated in this document focuses on the maintained in other equipments, e.g. customer premises equipment or
carrier-side stateless IPv4 over IPv6 solution. In the context of host.
address sharing, states should be maintained in other equipments,
e.g. customer premises equipment or host.
This document provides elaboration on the need for carrier-side This document focuses on carrier-side stateless IPv4 over IPv6.
stateless IPv4 over IPv6 solution.
More discussions about stateless vs. stateful can be found at More discussions about stateless vs. stateful can be found at
[RFC6144]. [RFC6144].
2. Terminology 2. Terminology
This document makes use of the following terms: This document makes use of the following terms:
State: as used in [RFC1958]. State: as used in [RFC1958].
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are routed to the right node. Note, TCP/UDP sessions are are routed to the right node. Note, TCP/UDP sessions are
uniquely identified by the tuple of (source IP address, source uniquely identified by the tuple of (source IP address, source
TCP/UDP port, target IP address, target TCP/UDP port) while ICMP TCP/UDP port, target IP address, target TCP/UDP port) while ICMP
query sessions are identified by the tuple of (source IP query sessions are identified by the tuple of (source IP
address, ICMP query ID, target IP address). address, ICMP query ID, target IP address).
User-session state: refers to session state belonging to a given User-session state: refers to session state belonging to a given
user. user.
Stateful 4/6 solution (or stateful solution in short): denotes a Stateful 4/6 solution (or stateful solution in short): denotes a
solution where the network maintains user-session states relying solution where a NAT in the Service Provider's network maintains
on the activation of a NAT function in the Service Providers' user-session states [I-D.ietf-behave-lsn-requirements]. The NAT
network [I-D.ietf-behave-lsn-requirements]. The NAT function is function is responsible for sharing the same IPv4 address among
responsible for sharing the same IPv4 address among several several subscribers and for maintaining user-session state.
subscribers and to maintain user-session state.
Stateless 4/6 solution (or stateless solution in short): denotes a Stateless 4/6 solution (or stateless solution in short): denotes a
solution which does not require any per-user state (see Section solution which does not require any per-user state (see Section
2.3 of [RFC1958]) to be maintained by any IP address sharing 2.3 of [RFC1958]) to be maintained by any IP address sharing
function in the Service Provider's network. This category of function in the Service Provider's network. A dependency
solutions assumes a dependency between an IPv6 prefix and IPv4 between an IPv6 prefix and IPv4 address is assumed. In an IPv4
address. In an IPv4 address sharing context, dedicated address sharing context, dedicated functions are enabled in the
functions are required to be enabled in the CPE router to CPE router to restrict the source IPv4 port numbers. Within
restrict the source IPv4 port numbers. Within this document, this document, "port set" and "port range" terms are used
"port set" and "port range" terms are used interchangeably. interchangeably.
3. Why Stateless IPv4 over IPv6 Solutions are Needed? 3. Why Stateless IPv4 over IPv6 Solutions are Needed?
Below is provided a list of motivations which justify the need for a The following sub-sections discuss different aspects that motivate
stateless solution (in no particular order): this effort.
(1) Minimizes impact on OSS and logging systems. Ideally, it does
not require OSS & logging systems that wouldn't be there in a
pure IPv6 network.
(2) Does not require maintaining per-subscriber configuration on
active data plane network elements.
(3) Scales in terms of IP forwarding capacity, rather than amount
of dynamic state, or new session creation rate.
(4) Supports a single architecture that allows 1:1 or N:1 (port
range) NAT44 usage without additional extensions.
(5) Preserves current engineering practices (e.g., anycast-based
load-balancing).
(6) Relies on IPv6 and supports transition to an IPv6-only network.
(7) Supports asymmetric routing to/from the IPv4 Internet.
(8) Maximizes the ease of deployment and redundancy of nodes.
(9) Readily supports a multi-vendor environment (including
redundancy).
(10) Allows direct user-user traffic flows (i.e., allows for no-
tromboning)
(11) Retains today's user experience (NAT on CPE) and supports
today's operational model.
(12) Does not require deployment of (additional) dynamic signaling
protocols to the end-user CPE beyond those already used.
(13) Minimizes required non-regression testing effort.
(14) Does not require organizational changes.
(15) Assumes a clear separation between the service and the network
layer and therefore there is no interference between delivered
services and underlying network transfer capabilities.
This section elaborates further on the aforementioned motivations.
3.1. Network Architecture Simplification 3.1. Network Architecture Simplification
The activation of the stateless function in the Service Provider's The activation of the stateless function in the Service Provider's
network does not introduce any major constraint on the network network does not introduce any major constraint on the network
architecture and its engineering. The following sub-sections architecture and its engineering. The following sub-sections
elaborate on these aspects. elaborate on these aspects.
3.1.1. Network Dimensioning 3.1.1. Network Dimensioning
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does not need to take into account the maximum number of simultaneous does not need to take into account the maximum number of simultaneous
user-sessions and the maximum number of new user-sessions per second user-sessions and the maximum number of new user-sessions per second
to dimension its networking equipment. Like current network to dimension its networking equipment. Like current network
dimensioning practices, only considerations related to the customers dimensioning practices, only considerations related to the customers
number, traffic trends and the bandwidth usage need be taken into number, traffic trends and the bandwidth usage need be taken into
account. account.
3.1.2. No Intra-domain Constraint 3.1.2. No Intra-domain Constraint
Stateless IPv4/IPv6 interconnection functions can be ideally located Stateless IPv4/IPv6 interconnection functions can be ideally located
at the boundaries of an Autonomous System (e.g., ASBRs that peer with at the boundaries of an Autonomous System (e.g., Autonomous System
external IPv4 domains); in such case intra-domain paths are not Border Routers (ASBRs) that peer with external IPv4 domains); in such
altered: there is no need to force IP packets to cross a given node case intra-domain paths are not altered: there is no need to force IP
for instance; intra-domain routing processes are not tweaked to packets to cross a given node for instance; intra-domain routing
direct the traffic to dedicated nodes. Stateless solutions optimize processes are not tweaked to direct the traffic to dedicated nodes.
CPE-to-CPE communication in that packets don't go through the Stateless solutions optimize CPE-to-CPE communication in that packets
interconnection function. don't go through the interconnection function.
3.1.3. Logging - No Need for Dynamic Binding Notifications 3.1.3. Logging - No Need for Dynamic Binding Notifications
Network abuse reporting requires traceability [RFC6269]. To provide Network abuse reporting requires traceability [RFC6269]. To provide
such traceability, prior to IPv4 address sharing, logging the IPv4 such traceability, prior to IPv4 address sharing, logging the IPv4
address assigned to a user was sufficient and generates relatively address assigned to a user was sufficient and generates relatively
small logs. The advent of stateful IPv4 address allows dynamic port small logs. The advent of stateful IPv4 address allows dynamic port
assignment, which then requires port assignment logging. This assignment, which then requires port assignment logging. This
logging of port assignments can be considerable. logging of port assignments can be considerable.
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If a dynamic port assignment mode is used, dedicated interfaces and If a dynamic port assignment mode is used, dedicated interfaces and
protocols must be supported to forward binding data records towards protocols must be supported to forward binding data records towards
dedicated platforms. The activation of these dynamic notifications dedicated platforms. The activation of these dynamic notifications
may impact the performance of the dedicated device. For stateless may impact the performance of the dedicated device. For stateless
solutions, there is no need for dynamic procedures (e.g., using solutions, there is no need for dynamic procedures (e.g., using
SYSLOG) to notify a mediation platform about assigned bindings. SYSLOG) to notify a mediation platform about assigned bindings.
Some Service Providers have a requirement to use only existing Some Service Providers have a requirement to use only existing
logging systems and to avoid introducing new ones (mainly because of logging systems and to avoid introducing new ones (mainly because of
CAPEX considerations). This requirement is easily met with stateless Capital Expenditure (CAPEX) considerations). This requirement is
solutions. easily met with stateless solutions.
3.1.4. No Additional Protocol for Port Control is Required 3.1.4. No Additional Protocol for Port Control is Required
Stateless solutions do not require activating a new dynamic signaling Stateless solutions do not require activating a new dynamic signaling
protocol in the end-user CPE in addition to those already used. In protocol in the end-user CPE in addition to those already used. In
particular, existing protocols (e.g., UPnP IGD:2 [UPnP-IGD]) can be particular, existing protocols (e.g., UPnP IGD:2 [UPnP-IGD]) can be
used to control the NAT mappings in the CPE. used to control the NAT mappings in the CPE.
Note: To overcome some security concerns, IGD:2 authorization
framework [UPnP-IGD] should be used and security considerations
elaborated in [Sec_DCP] should be taken into account.
3.2. Operational Tasks and Network Maintenance Efficiency 3.2. Operational Tasks and Network Maintenance Efficiency
3.2.1. Preserve Current Practices 3.2.1. Preserve Current Practices
Service Providers require as much as possible to preserve the same
operations as for current IP networking environments.
If stateless solutions are deployed, common practices are preserved. If stateless solutions are deployed, common practices are preserved.
In particular, the maintenance and operation of the network do not In particular, the maintenance and operation of the network do not
require any additional constraints such as: path optimization require any additional constraints such as: path optimization
practices, enforcing traffic engineering policies, issues related to practices, enforcing traffic engineering policies, issues related to
traffic oscillation between stateful devices, load-balancing the traffic oscillation between stateful devices, load-balancing the
traffic or load sharing the traffic among egress/ingress points can traffic or load sharing the traffic among egress/ingress points can
be used, etc. Particularly, be used, etc. Particularly,
o anycast-based schemes can be used for load-balancing and o anycast-based schemes can be used for load-balancing and
redundancy purposes. redundancy purposes between nodes embedding the Stateless IPv4/
IPv6 interconnection function.
o asymmetric routing to/from the IPv4 Internet is natively supported o asymmetric routing to/from the IPv4 Internet is natively supported
and no path-pinning mechanisms have to be additionally and no path-pinning mechanisms have to be additionally
implemented. implemented.
3.2.2. Planned Maintenance Operations 3.2.2. Planned Maintenance Operations
Since no state is maintained by stateless IPv4/IPv6 interconnection Since no state is maintained by stateless IPv4/IPv6 interconnection
nodes, no additional constraint needs to be taken into account when nodes, no additional constraint needs to be taken into account when
upgrading these nodes (e.g., adding a new service card, upgrading upgrading these nodes (e.g., adding a new service card, upgrading
hardware, periodic reboot of the devices, etc.). In particular, hardware, periodic reboot of the devices, etc.). In particular,
current practices that are enforced to (gracefully) reboot or to current practices that are enforced to (gracefully) reboot or to
shutdown routers can be maintained. shutdown routers can be maintained.
3.2.3. Reliability and Robustness 3.2.3. Reliability and Robustness
Compared to current practices (i.e., without a CGN in place), no Compared to current practices (i.e., without a Carrier Grade NAT
additional capabilities are required to ensure reliability and (CGN) in place), no additional capabilities are required to ensure
robustness in the context of stateless solutions. Since no state is reliability and robustness in the context of stateless solutions.
maintained in the Service Provider's network, state synchronization Since no state is maintained in the Service Provider's network, state
procedures are not required. synchronization procedures are not required.
High availability (including failure recovery) is ensured owing to High availability (including failure recovery) is ensured owing to
best current practices in the field. best current practices in the field.
3.2.4. Support of Multi-Vendor Redundancy 3.2.4. Support of Multi-Vendor Redundancy
Deploying stateful techniques, especially when used in the Service Deploying stateful techniques, especially when used in the Service
Providers networks, constrains severely deploying multi-vendor Providers networks, constrains severely deploying multi-vendor
redundancy since very often proprietary vendor-specific protocols are redundancy since very often proprietary vendor-specific protocols are
used to synchronize state. This is not an issue for the stateless used to synchronize state. This is not an issue for the stateless
case. Concretely, the activation of the stateless IPv4/IPv6 case. Concretely, the activation of the stateless IPv4/IPv6
interconnection function does not prevent nor complicate deploying interconnection function does not prevent nor complicate deploying
devices from different vendors. devices from different vendors.
This criterion is very important for Service Providers having a This criterion is very important for Service Providers because they
sourcing policy to avoid mono-vendor deployments and to operate want to avoid being locked into one vendor for their entire network
highly-available networks composed on multi-vendors equipment. and they want to operate multi-vendor-supplied networks.
3.2.5. Simplification of Qualification Procedures 3.2.5. Simplification of Qualification Procedures
The introduction of new functions and nodes into operational networks The introduction of new functions and nodes into operational networks
follows strict procedures elaborated by Service Providers. These follows strict procedures elaborated by Service Providers. These
procedures include in-lab testing and field trials. Because of their procedures include in-lab testing and field trials. Because of their
nature, stateless implementations optimize testing time and nature, stateless implementations optimize testing time and
procedures: procedures:
o The specification of test suites to be conducted should be o The specification of test suites to be conducted should be
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3.3.1. Implicit Host Identification 3.3.1. Implicit Host Identification
Service Providers do not offer only IP connectivity services but also Service Providers do not offer only IP connectivity services but also
added value services (a.k.a., internal services). Upgrading these added value services (a.k.a., internal services). Upgrading these
services to be IPv6-enabled is not sufficient because of legacy services to be IPv6-enabled is not sufficient because of legacy
devices. In some deployments, the delivery of these added-value devices. In some deployments, the delivery of these added-value
services relies on implicit identification mechanism based on the services relies on implicit identification mechanism based on the
source IPv4 address. Due to address sharing, implicit identification source IPv4 address. Due to address sharing, implicit identification
will fail [RFC6269]; replacing implicit identification with explicit will fail [RFC6269]; replacing implicit identification with explicit
authentication will be seen as a non acceptable service regression by authentication will be seen as a non acceptable service regression by
the end users (less Quality of Experience (QoE)). the end users (less Quality of Experience (QoE); refer to Section 4.2
[RFC6462]).
When a stateless solution is deployed, implicit identification for When a stateless solution is deployed, implicit identification for
internal services is likely to be easier to implement: the implicit internal services is likely to be easier to implement: the implicit
identification should be updated to take into account the port range identification should be updated to take into account the port range
and the IPv4 address. Techniques as those analyzed in and the IPv4 address. Techniques as those analyzed in
[I-D.ietf-intarea-nat-reveal-analysis] are not required for the [I-D.ietf-intarea-nat-reveal-analysis] are not required for the
delivery of these internal services if a stateless solution is delivery of these internal services if a stateless solution is
deployed. deployed.
Note stateful approaches configured to assign port ranges allow also Note stateful approaches configured to assign port ranges allow also
to support implicit host identification. to support implicit host identification.
3.3.2. No Organizational Impact 3.3.2. No Organizational Impact
Stateless solutions adopt a clear separation between the IP/transport Stateless solutions adopt a clear separation between the IP/transport
layers and the service layers; no service interference is to be layers and the service layers; no service interference is to be
observed when a stateless solution is deployed. This clear observed when a stateless solution is deployed. This clear
separation: separation:
Facilitates service evolution: Since the payload of IPv4 packets is Facilitates service evolution: Stateless solutions admit
not altered in the path, services can evolve without requiring any applications which can be deployed without enabling any
specific function (e.g., Application Level Gateway (ALG)) in the application-specific function (e.g., Application Level Gateway
Service Provider's network; (ALG)) in the Service Provider's network. Avoiding ALGs is highly
desirable.
Limits vendor dependency: The upgrade of value-added services does Limits vendor dependency: The upgrade of value-added services does
not involve any particular action from vendors that provide not involve any particular action from vendors that provide
devices embedding the stateless IPv4/IPv6 interconnection devices embedding the stateless IPv4/IPv6 interconnection
function. function.
No service-related skills are required for network operators who No service-related skills are required for network operators who
manage devices that embed the IPv4/IPv6 interconnection function: IP manage devices that embed the IPv4/IPv6 interconnection function: IP
teams can be in charge of these devices; there is a priori no need teams can be in charge of these devices; there is a priori no need
to create a dedicated team to manage and to operate devices to create a dedicated team to manage and to operate devices
embedding the stateless IPv4/IPv6 interconnection function. The embedding the stateless IPv4/IPv6 interconnection function. The
introduction of stateless capabilities in the network are unlikely introduction of stateless capabilities in the network are unlikely
to degrade management costs. to degrade management costs.
3.4. Cost Minimization Opportunities 3.4. Cost Minimization Opportunities
To make decision for which solution is to be adopted, Service To make decision for which solution is to be adopted, Service
Providers usually undertake comparative studies about viable Providers usually undertake comparative studies about viable
technical solutions. It is not only about technical aspects but also technical solutions. It is not only about technical aspects but also
economical optimization (both CAPEX and OPEX considerations). From a economical optimization (both CAPEX and Operational Expenditure
Service Provider perspective, stateless solutions are more attractive (OPEX) considerations). From a Service Provider perspective,
because they do less impact the current network operations and stateless solutions may be more attractive because it impacts the
maintenance model that is widely based on stateless approaches. current network operations and maintenance model less than stateful
Table 1 shows the general correspondence between technical benefits solutions. Table 1 shows the general correspondence between
and potential economic reduction opportunities. technical benefits and potential economic reduction opportunities.
While not all Service Providers environments are the same, a detailed While not all Service Providers environments are the same, a detailed
case study from one Service Provider case study from one Service Provider
[I-D.matsushima-v6ops-transition-experience] reports that stateless [I-D.matsushima-v6ops-transition-experience] reports that stateless
transition solutions can be considerably less expensive than stateful transition solutions can be considerably less expensive than stateful
transition solutions. transition solutions.
+---------------+--------------------------------------+------------+ +---------------+--------------------------------------+------------+
| Section | Technical and Operation Benefit | Cost Area | | Section | Technical and Operation Benefit | Cost Area |
+---------------+--------------------------------------+------------+ +---------------+--------------------------------------+------------+
skipping to change at page 13, line 37 skipping to change at page 12, line 41
Many thanks to the following individuals who provided valuable Many thanks to the following individuals who provided valuable
comments: comments:
+---------------+---------------+---------------+---------------+ +---------------+---------------+---------------+---------------+
| X. Deng | W. Dec | D. Wing | A. Baudot | | X. Deng | W. Dec | D. Wing | A. Baudot |
| E. Burgey | L. Cittadini | R. Despres | J. Zorz | | E. Burgey | L. Cittadini | R. Despres | J. Zorz |
| M. Townsley | L. Meillarec | R. Maglione | J. Queiroz | | M. Townsley | L. Meillarec | R. Maglione | J. Queiroz |
| C. Xie | X. Li | O. Troan | J. Qin | | C. Xie | X. Li | O. Troan | J. Qin |
| B. Sarikaya | N. Skoberne | J. Arkko | D. Lui | | B. Sarikaya | N. Skoberne | J. Arkko | D. Lui |
+---------------+---------------+---------------+---------------+ +---------------+---------------+---------------+---------------+
Special thanks to W. Dec who provided a summary of the motivation
items.
10. Informative References 10. Informative References
[EURESCOM] [EURESCOM]
Levis, P., Borges, I., Bonness, O. and L. Dillon L., "IPv4 Levis, P., Borges, I., Bonness, O. and L. Dillon L., "IPv4
address exhaustion: Issues and Solutions for Service address exhaustion: Issues and Solutions for Service
Providers", March 2010, <http://archive.eurescom.eu/~pub/ Providers", March 2010, <http://archive.eurescom.eu/~pub/
deliverables/documents/P1900-series/P1952/D2bis/ deliverables/documents/P1900-series/P1952/D2bis/
P1952-D2bis.pdf>. P1952-D2bis.pdf>.
[I-D.ietf-behave-lsn-requirements] [I-D.ietf-behave-lsn-requirements]
skipping to change at page 15, line 9 skipping to change at page 14, line 9
IPv4/IPv6 Translation", RFC 6144, April 2011. IPv4/IPv6 Translation", RFC 6144, April 2011.
[RFC6269] Ford, M., Boucadair, M., Durand, A., Levis, P., and P. [RFC6269] Ford, M., Boucadair, M., Durand, A., Levis, P., and P.
Roberts, "Issues with IP Address Sharing", RFC 6269, Roberts, "Issues with IP Address Sharing", RFC 6269,
June 2011. June 2011.
[RFC6324] Nakibly, G. and F. Templin, "Routing Loop Attack Using [RFC6324] Nakibly, G. and F. Templin, "Routing Loop Attack Using
IPv6 Automatic Tunnels: Problem Statement and Proposed IPv6 Automatic Tunnels: Problem Statement and Proposed
Mitigations", RFC 6324, August 2011. Mitigations", RFC 6324, August 2011.
[RFC6462] Cooper, A., "Report from the Internet Privacy Workshop",
RFC 6462, January 2012.
[Sec_DCP] UPnP Forum, "Device Protection:1", November 2009.
[UPnP-IGD] [UPnP-IGD]
UPnP Forum, "Universal Plug and Play (UPnP) Internet UPnP Forum, "Universal Plug and Play (UPnP) Internet
Gateway Device (IGD) V 2.0", December 2010, Gateway Device (IGD) V 2.0", December 2010,
<http://upnp.org/specs/gw/igd2/>. <http://upnp.org/specs/gw/igd2/>.
Authors' Addresses Authors' Addresses
Mohamed Boucadair (editor) Mohamed Boucadair (editor)
France Telecom France Telecom
Rennes, 35000 Rennes, 35000
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