draft-ietf-dmm-ondemand-mobility-14.txt   draft-ietf-dmm-ondemand-mobility-15.txt 
DMM Working Group A. Yegin DMM Working Group A. Yegin
Internet-Draft Actility Internet-Draft Actility
Intended status: Informational D. Moses Intended status: Informational D. Moses
Expires: September 20, 2018 Intel Expires: January 27, 2019 Intel
K. Kweon K. Kweon
J. Lee J. Lee
J. Park J. Park
Samsung Samsung
S. Jeon S. Jeon
Sungkyunkwan University Sungkyunkwan University
March 19, 2018 July 26, 2018
On Demand Mobility Management On Demand Mobility Management
draft-ietf-dmm-ondemand-mobility-14 draft-ietf-dmm-ondemand-mobility-15
Abstract Abstract
Applications differ with respect to whether they need IP session Applications differ with respect to whether they need session
continuity and/or IP address reachability. The network providing the continuity and/or IP address reachability. The network providing the
same type of service to any mobile host and any application running same type of service to any mobile host and any application running
on the host yields inefficiencies. This document describes a on the host yields inefficiencies. This document describes a
solution for taking the application needs into account by selectively solution for taking the application needs into account by selectively
providing IP session continuity and IP address reachability on a per- providing session continuity and IP address reachability on a per-
socket basis. socket basis.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
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 https://datatracker.ietf.org/drafts/current/. Drafts is at https://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 September 20, 2018. This Internet-Draft will expire on January 27, 2019.
Copyright Notice Copyright Notice
Copyright (c) 2018 IETF Trust and the persons identified as the Copyright (c) 2018 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of (https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
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include Simplified BSD License text as described in Section 4.e of include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Notational Conventions . . . . . . . . . . . . . . . . . . . 4 2. Notational Conventions . . . . . . . . . . . . . . . . . . . 4
3. Solution . . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Solution . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3.1. Types of IP Addresses . . . . . . . . . . . . . . . . . . 4 3.1. Types of IP Addresses . . . . . . . . . . . . . . . . . . 4
3.2. Granularity of Selection . . . . . . . . . . . . . . . . 5 3.2. Granularity of Selection . . . . . . . . . . . . . . . . 6
3.3. On Demand Nature . . . . . . . . . . . . . . . . . . . . 6 3.3. On Demand Nature . . . . . . . . . . . . . . . . . . . . 6
3.4. Conveying the Desired Address Type . . . . . . . . . . . 7 3.4. Conveying the Desired Address Type . . . . . . . . . . . 7
4. Usage example . . . . . . . . . . . . . . . . . . . . . . . . 8 4. Usage example . . . . . . . . . . . . . . . . . . . . . . . . 8
5. Backwards Compatibility Considerations . . . . . . . . . . . 10 4.1. Pseudo-code example . . . . . . . . . . . . . . . . . . . 8
5.1. Applications . . . . . . . . . . . . . . . . . . . . . . 10 4.2. Message Flow example . . . . . . . . . . . . . . . . . . 10
5.2. IP Stack in the Mobile Host . . . . . . . . . . . . . . . 10 5. Backwards Compatibility Considerations . . . . . . . . . . . 11
5.3. Network Infrastructure . . . . . . . . . . . . . . . . . 10 5.1. Applications . . . . . . . . . . . . . . . . . . . . . . 11
5.4. Merging this work with RFC5014 . . . . . . . . . . . . . 11 5.2. IP Stack in the Mobile Host . . . . . . . . . . . . . . . 12
6. Summary of New Definitions . . . . . . . . . . . . . . . . . 11 5.3. Network Infrastructure . . . . . . . . . . . . . . . . . 12
6.1. New APIs . . . . . . . . . . . . . . . . . . . . . . . . 11 5.4. Merging this work with RFC5014 . . . . . . . . . . . . . 12
6.2. New Flags . . . . . . . . . . . . . . . . . . . . . . . . 12 6. Summary of New Definitions . . . . . . . . . . . . . . . . . 13
7. Security Considerations . . . . . . . . . . . . . . . . . . . 13 6.1. New APIs . . . . . . . . . . . . . . . . . . . . . . . . 13
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13 6.2. New Flags . . . . . . . . . . . . . . . . . . . . . . . . 13
9. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 13 7. Security Considerations . . . . . . . . . . . . . . . . . . . 14
10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 13 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 13 9. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 14
11.1. Normative References . . . . . . . . . . . . . . . . . . 13 10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 14
11.2. Informative References . . . . . . . . . . . . . . . . . 14 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 14
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 15 11.1. Normative References . . . . . . . . . . . . . . . . . . 15
11.2. Informative References . . . . . . . . . . . . . . . . . 15
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 16
1. Introduction 1. Introduction
In the context of Mobile IP [RFC5563][RFC6275][RFC5213][RFC5944], the In the context of Mobile IP [RFC5563][RFC6275][RFC5213][RFC5944], the
following two attributes are defined for IP service provided to following two attributes are defined for IP service provided to
mobile hosts: mobile hosts:
IP session continuity: The ability to maintain an ongoing IP session Session continuity: The ability to maintain an ongoing transport
by keeping the same local end-point IP address throughout the session interaction by keeping the same local end-point IP address throughout
despite the mobile host changing its point of attachment within the the life-time of the IP socket despite the mobile host changing its
IP network topology. The IP address of the host may change between point of attachment within the IP network topology. The IP address
two independent IP sessions, but that does not jeopardize its IP of the host may change after closing the IP socket and before opening
session continuity. IP session continuity is essential for mobile a new one, but that does not jeopardize the ability of applications
hosts to maintain ongoing flows without any interruption. using these IP sockets to work flawlessly. Session continuity is
essential for mobile hosts to maintain ongoing flows without any
interruption.
IP address reachability: The ability to maintain the same IP address IP address reachability: The ability to maintain the same IP address
for an extended period of time. The IP address stays the same across for an extended period of time. The IP address stays the same across
independent IP sessions, and even in the absence of any IP session. independent sessions, and even in the absence of any session. The IP
The IP address may be published in a long-term registry (e.g., DNS), address may be published in a long-term registry (e.g., DNS), and is
and is made available for serving incoming (e.g., TCP) connections. made available for serving incoming (e.g., TCP) connections. IP
IP address reachability is essential for mobile hosts to use address reachability is essential for mobile hosts to use specific/
specific/published IP addresses. published IP addresses.
Mobile IP is designed to provide both IP session continuity and IP Mobile IP is designed to provide both session continuity and IP
address reachability to mobile hosts. Architectures utilizing these address reachability to mobile hosts. Architectures utilizing these
protocols (e.g., 3GPP, 3GPP2, WIMAX) ensure that any mobile host protocols (e.g., 3GPP, 3GPP2, WIMAX) ensure that any mobile host
attached to the compliant networks can enjoy these benefits. Any attached to the compliant networks can enjoy these benefits. Any
application running on these mobile hosts is subjected to the same application running on these mobile hosts is subjected to the same
treatment with respect to IP session continuity and IP address treatment with respect to session continuity and IP address
reachability. reachability.
It should be noted that in reality not every application may need It should be noted that in reality not every application may need
these benefits. IP address reachability is required for applications these benefits. IP address reachability is required for applications
running as servers (e.g., a web server running on the mobile host). running as servers (e.g., a web server running on the mobile host).
But, a typical client application (e.g., web browser) does not But, a typical client application (e.g., web browser) does not
necessarily require IP address reachability. Similarly, IP session necessarily require IP address reachability. Similarly, session
continuity is not required for all types of applications either. continuity is not required for all types of applications either.
Applications performing brief communication (e.g., ping) can survive Applications performing brief communication (e.g., ping) can survive
without having IP session continuity support. without having session continuity support.
Achieving IP session continuity and IP address reachability with Achieving session continuity and IP address reachability with Mobile
Mobile IP incurs some cost. Mobile IP protocol forces the mobile IP incurs some cost. Mobile IP protocol forces the mobile host's IP
host's IP traffic to traverse a centrally-located router (Home Agent, traffic to traverse a centrally-located router (Home Agent, HA),
HA), which incurs additional transmission latency and use of which incurs additional transmission latency and use of additional
additional network resources, adds to the network CAPEX and OPEX, and network resources, adds to the network CAPEX and OPEX, and decreases
decreases the reliability of the network due to the introduction of a the reliability of the network due to the introduction of a single
single point of failure [RFC7333]. Therefore, IP session continuity point of failure [RFC7333]. Therefore, session continuity and IP
and IP address reachability SHOULD be provided only when necessary. address reachability SHOULD be provided only when necessary.
Furthermore, when an application needs session continuity, it may be Furthermore, when an application needs session continuity, it may be
able to satisfy that need by using a solution above the IP layer, able to satisfy that need by using a solution above the IP layer,
such as MPTCP [RFC6824], SIP mobility [RFC3261], or an application- such as MPTCP [RFC6824], SIP mobility [RFC3261], or an application-
layer mobility solution. These higher-layer solutions are not layer mobility solution. These higher-layer solutions are not
subject to the same issues that arise with the use of Mobile IP since subject to the same issues that arise with the use of Mobile IP since
they can utilize the most direct data path between the end-points. they can utilize the most direct data path between the end-points.
But, if Mobile IP is being applied to the mobile host, the higher- But, if Mobile IP is being applied to the mobile host, the higher-
layer protocols are rendered useless because their operation is layer protocols are rendered useless because their operation is
inhibited by Mobile IP. Since Mobile IP ensures that the IP address inhibited by Mobile IP. Since Mobile IP ensures that the IP address
of the mobile host remains fixed (despite the location and movement of the mobile host remains fixed (despite the location and movement
of the mobile host), the higher-layer protocols never detect the IP- of the mobile host), the higher-layer protocols never detect the IP-
layer change and never engage in mobility management. layer change and never engage in mobility management.
This document proposes a solution for applications running on mobile This document proposes a solution for applications running on mobile
hosts to indicate whether they need IP session continuity or IP hosts to indicate whether they need session continuity or IP address
address reachability. The network protocol stack on the mobile host, reachability. The network protocol stack on the mobile host, in
in conjunction with the network infrastructure, provides the required conjunction with the network infrastructure, provides the required
type of IP service. It is for the benefit of both the users and the type of service. It is for the benefit of both the users and the
network operators not to engage an extra level of service unless it network operators not to engage an extra level of service unless it
is absolutely necessary. It is expected that applications and is absolutely necessary. It is expected that applications and
networks compliant with this specification will utilize this solution networks compliant with this specification will utilize this solution
to use network resources more efficiently. to use network resources more efficiently.
2. Notational Conventions 2. Notational Conventions
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119]. document are to be interpreted as described in [RFC2119].
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- Fixed IP Address - Fixed IP Address
A Fixed IP address is an address with a guarantee to be valid for a A Fixed IP address is an address with a guarantee to be valid for a
very long time, regardless of whether it is being used in any packet very long time, regardless of whether it is being used in any packet
to/from the mobile host, or whether or not the mobile host is to/from the mobile host, or whether or not the mobile host is
connected to the network, or whether it moves from one point-of- connected to the network, or whether it moves from one point-of-
attachment to another (with a different IP prefix) while it is attachment to another (with a different IP prefix) while it is
connected. connected.
Fixed IP addresses are required by applications that need both IP Fixed IP addresses are required by applications that need both
session continuity and IP address reachability. session continuity and IP address reachability.
- Session-lasting IP Address - Session-lasting IP Address
A session-lasting IP address is an address with a guarantee to be A session-lasting IP address is an address with a guarantee to be
valid throughout the IP session(s) for which it was requested. It is valid throughout the life-time of the socket(s) for which it was
guaranteed to be valid even after the mobile host had moved from one requested. It is guaranteed to be valid even after the mobile host
point-of-attachment to another (with a different IP prefix). had moved from one point-of-attachment to another (with a different
IP prefix).
Session-lasting IP addresses are required by applications that need Session-lasting IP addresses are required by applications that need
IP session continuity but do not need IP address reachability. session continuity but do not need IP address reachability.
- Non-persistent IP Address - Non-persistent IP Address
This type of IP address does not provide IP session continuity nor IP This type of IP address has no guarantee to exist after a mobile host
address reachability. The IP address is created from an IP prefix moves from one point-of-attachment to another, and therefore, no
that is obtained from the serving IP gateway and is not maintained session continuity nor IP address reachability are provided. The IP
across gateway changes. In other words, the IP prefix may be address is created from an IP prefix that is obtained from the
released and replaced by a new one when the IP gateway changes due to serving IP gateway and is not maintained across gateway changes. In
the movement of the mobile host forcing the creation of a new source other words, the IP prefix may be released and replaced by a new one
IP address with the updated allocated IP prefix. when the IP gateway changes due to the movement of the mobile host
forcing the creation of a new source IP address with the updated
allocated IP prefix.
- Graceful Replacement IP Address - Graceful Replacement IP Address
In some cases, the network cannot guarantee the validity of the In some cases, the network cannot guarantee the validity of the
provided IP prefix throughout the duration of the IP session, but can provided IP prefix throughout the duration of the opened socket, but
provide a limited graceful period of time in which both the original can provide a limited graceful period of time in which both the
IP prefix and a new one are valid. This enables the application some original IP prefix and a new one are valid. This enables the
flexibility in the transition from the existing source IP address to application some flexibility in the transition from the existing
the new one. source IP address to the new one.
This gracefulness is still better than the non-persistence type of This gracefulness is still better than the non-persistence type of
address for applications that can handle a change in their source IP address for applications that can handle a change in their source IP
address but require that extra flexibility. address but require that extra flexibility.
Applications running as servers at a published IP address require a Applications running as servers at a published IP address require a
Fixed IP Address. Long-standing applications (e.g., an SSH session) Fixed IP Address. Long-standing applications (e.g., an SSH session)
may also require this type of address. Enterprise applications that may also require this type of address. Enterprise applications that
connect to an enterprise network via virtual LAN require a Fixed IP connect to an enterprise network via virtual LAN require a Fixed IP
Address. Address.
Applications with short-lived transient IP sessions can use Session- Applications with short-lived transient sessions can use Session-
lasting IP Addresses. For example: Web browsers. lasting IP Addresses. For example: Web browsers.
Applications with very short IP sessions, such as DNS clients and Applications with very short sessions, such as DNS clients and
instant messengers, can utilize Non-persistent IP Addresses. Even instant messengers, can utilize Non-persistent IP Addresses. Even
though they could very well use Fixed or Session-lasting IP though they could very well use Fixed or Session-lasting IP
Addresses, the transmission latency would be minimized when a Non- Addresses, the transmission latency would be minimized when a Non-
persistent IP Addresses are used. persistent IP Addresses are used.
Applications that can tolerate a short interruption in connectivity Applications that can tolerate a short interruption in connectivity
can use the Graceful-replacement IP addresses. For example, a can use the Graceful-replacement IP addresses. For example, a
streaming client that has buffering capabilities. streaming client that has buffering capabilities.
3.2. Granularity of Selection 3.2. Granularity of Selection
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the operation fails, the IP stack SHALL fail the associated socket the operation fails, the IP stack SHALL fail the associated socket
request and return an error. If successful, a Session-lasting IP request and return an error. If successful, a Session-lasting IP
Address gets configured on the mobile host. If another socket Address gets configured on the mobile host. If another socket
requests a Session-lasting IP address at a later time, the same IP requests a Session-lasting IP address at a later time, the same IP
address may be served to that socket as well. When the last socket address may be served to that socket as well. When the last socket
using the same configured IP address is closed, the IP address may be using the same configured IP address is closed, the IP address may be
released or kept for future applications that may be launched and released or kept for future applications that may be launched and
require a Session-lasting IP address. require a Session-lasting IP address.
In some cases it might be preferable for the mobile host to request a In some cases it might be preferable for the mobile host to request a
new Session-lasting IP address for a new opening of an IP session new Session-lasting IP address for a new opening of an IP socket
(even though one was already assigned to the mobile host by the (even though one was already assigned to the mobile host by the
network and might be in use in a different, already active IP network and might be in use in a different, already active IP
session). It is outside the scope of this specification to define sockets). It is outside the scope of this specification to define
criteria for choosing to use available addresses or choosing to criteria for choosing to use available addresses or choosing to
request new ones. It supports both alternatives (and any request new ones. It supports both alternatives (and any
combination). combination).
It is outside the scope of this specification to define how the host It is outside the scope of this specification to define how the host
requests a specific type of prefix and how the network indicates the requests a specific type of prefix and how the network indicates the
type of prefix in its advertisement or in its reply to a request). type of prefix in its advertisement or in its reply to a request).
The following are matters of policy, which may be dictated by the The following are matters of policy, which may be dictated by the
host itself, the network operator, or the system architecture host itself, the network operator, or the system architecture
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source address selection with the IPV6_ADDR_PREFERENCE option at the source address selection with the IPV6_ADDR_PREFERENCE option at the
IPPROTO_IPV6 level. This option is used with setsockopt() and IPPROTO_IPV6 level. This option is used with setsockopt() and
getsockopt() calls to set/get address selection preferences. getsockopt() calls to set/get address selection preferences.
Extending this further by adding more flags does not work when a Extending this further by adding more flags does not work when a
request for an address of a certain type results in requiring the IP request for an address of a certain type results in requiring the IP
stack to wait for the network to provide the desired source IP prefix stack to wait for the network to provide the desired source IP prefix
and hence causing the setsockopt() call to block until the prefix is and hence causing the setsockopt() call to block until the prefix is
allocated (or an error indication from the network is received). allocated (or an error indication from the network is received).
Alternatively a new Socket API is defined - getsc() which allows Alternatively a new socket API is defined - getsc() which allows
applications to express their desired type of session continuity applications to express their desired type of session continuity
service. The new getsc() API will return an IPv6 address that is service. The new getsc() API will return an IPv6 address that is
associated with the desired session continuity service and with associated with the desired session continuity service and with
status information indicating whether or not the desired service was status information indicating whether or not the desired service was
provided. provided.
An application that wishes to secure a desired service will call An application that wishes to secure a desired service will call
getsc() with the service type definition and a place to contain the getsc() with the service type definition and a place to contain the
provided IP address, and call bind() to associate that IP address provided IP address, and call bind() to associate that IP address
with the Socket (See pseudo-code example in Section 4 below). with the socket (See pseudo-code example in Section 4 below).
When the IP stack is required to use a source IP address of a When the IP stack is required to use a source IP address of a
specified type, it can use an existing address, or request a new IP specified type, it can use an existing address, or request a new IP
prefix (of the same type) from the network and create a new one. If prefix (of the same type) from the network and create a new one. If
the host does not already have an IPv6 prefix of that specific type, the host does not already have an IPv6 prefix of that specific type,
it MUST request one from the network. it MUST request one from the network.
Using an existing address from an existing prefix is faster but might Using an existing address from an existing prefix is faster but might
yield a less optimal route (if a hand-off event occurred after its yield a less optimal route (if a hand-off event occurred after its
configuration). On the other hand, acquiring a new IP prefix from configuration). On the other hand, acquiring a new IP prefix from
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preconfigured source IP address (if exists) or to request a new IPv6 preconfigured source IP address (if exists) or to request a new IPv6
prefix from the current serving network and configure a new IP prefix from the current serving network and configure a new IP
address. address.
This new flag is added to the set of flags in the This new flag is added to the set of flags in the
IPV6_ADDR_PREFERENCES option at the IPPROTO_IPV6 level. It is used IPV6_ADDR_PREFERENCES option at the IPPROTO_IPV6 level. It is used
in setsockopt() to set the desired behavior. in setsockopt() to set the desired behavior.
4. Usage example 4. Usage example
4.1. Pseudo-code example
The following example shows pseudo-code for creating a Stream socket The following example shows pseudo-code for creating a Stream socket
(TCP) with a Session-Lasting source IP address: (TCP) with a Session-Lasting source IP address:
#include <sys/socket.h> #include <sys/socket.h>
#include <netinnet/in.h> #include <netinnet/in.h>
// Socket information // Socket information
int s ; // Socket id int s ; // socket id
// Source information (for secsc() and bind()) // Source information (for secsc() and bind())
sockaddr_in6 sourceInfo // my address and port for bind() sockaddr_in6 sourceInfo // my address and port for bind()
in6_addr sourceAddress // will contain the provisioned in6_addr sourceAddress // will contain the provisioned
// source IP address // source IP address
uint8_t sc_type = IPV6_REQUIRE_SESSION_LASTING_IP ; uint8_t sc_type = IPV6_REQUIRE_SESSION_LASTING_IP ;
// For requesting a Session-Lasting // For requesting a Session-Lasting
// source IP address // source IP address
// Destination information (for connect()) // Destination information (for connect())
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// application code that does not use Session-lasting IP // application code that does not use Session-lasting IP
// address. The application may either connect without // address. The application may either connect without
// the desired Session-lasting service, or close the // the desired Session-lasting service, or close the
// socket... // socket...
} // if setsc() failed } // if setsc() failed
} // if socket was created successfully } // if socket was created successfully
// The rest of the application's code // The rest of the application's code
// ... // ...
4.2. Message Flow example
The following message flow illustrates a possible interaction for
achieving OnDemand functionality. It is an example of one scenario
and should not be regarded as the only scenario or the preferred one.
This flow describes the interaction between the following entities:
- Applications requiring different types of OnDemand service.
- The mobile host's IP stack.
- The network infrastructure providing the services.
In this example, the network infrastructure provides 2 IPv6 prefixes
upon attachment of the mobile host to the network: A Session-lasting
IPv6 prefix and a Non-persistent IPv6 prefix. Whenever the mobile
host moves to a different point-of-attachment, the network
infrastructure provides a new Non-persistent IPv6 address.
In this example, the network infrastructure does not support Fixed IP
addresses nor Graceful-replacement IP addresses.
Whenever an application opens an IP socket and requests a specific
IPv6 address type, the IP stack will provide one from its available
IPv6 prefixes or return an error message if the request cannot be
fulfilled.
Message Flow:
- The mobile device attaches to the network.
- The Network provides two IPv6 prefixes: PREFsl1 - a Session-lasting
IPv6 prefix and PREFnp1 - a Non-persistent IP v6 prefix.
- An application on the mobile host is launched. It opens an IP
socket and requests a Non-persistent IPv6 address.
- The IP stack provides IPnp1 which is generated from PREFnp1.
- Another application is launched, requesting a Non-persistent IPv6
address.
- The IP stack provides IPnp1 again.
- A third application is launched. This time, it requires a Session-
lasting IPv6 address.
- The IP stack provides IPsl1 which is generated from PREFsl1.
- The mobile hosts moves to a new point-of-attachment.
- The network provides a new Non-persistent IPv6 prefix - PREFnp2.
PREFnp1 is no longer valid.
- The applications that were given IPnp1 re-establish the socket and
receive a new IPv6 address - IPnp2 which is generated from PREFnp2
- The application that is using IPsl1 can still use it since the
network guaranteed that PREFsl1 will be valid even after moving to a
new point-of-attachment.
- A new application is launched, this time requiring a Graceful-
replacement IPv6 address.
- The IP stack returns setsc() with an error since the network does
not support this service.
- The application re-attempts to open a socket, this time requesting
a Session-lasting IPv6 address.
- The IP stack provides IPsl1.
5. Backwards Compatibility Considerations 5. Backwards Compatibility Considerations
Backwards compatibility support is REQUIRED by the following 3 types Backwards compatibility support is REQUIRED by the following 3 types
of entities: of entities:
- The Applications on the mobile host - The Applications on the mobile host
- The IP stack in the mobile host - The IP stack in the mobile host
- The network infrastructure - The network infrastructure
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