--- 1/draft-ietf-dmm-ondemand-mobility-14.txt 2018-07-26 09:13:13.953523585 -0700 +++ 2/draft-ietf-dmm-ondemand-mobility-15.txt 2018-07-26 09:13:13.989524453 -0700 @@ -1,52 +1,52 @@ DMM Working Group A. Yegin Internet-Draft Actility Intended status: Informational D. Moses -Expires: September 20, 2018 Intel +Expires: January 27, 2019 Intel K. Kweon J. Lee J. Park Samsung S. Jeon Sungkyunkwan University - March 19, 2018 + July 26, 2018 On Demand Mobility Management - draft-ietf-dmm-ondemand-mobility-14 + draft-ietf-dmm-ondemand-mobility-15 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 same type of service to any mobile host and any application running on the host yields inefficiencies. This document describes a 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. Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at https://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference 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 (c) 2018 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents @@ -55,107 +55,111 @@ include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Notational Conventions . . . . . . . . . . . . . . . . . . . 4 3. Solution . . . . . . . . . . . . . . . . . . . . . . . . . . 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 3.4. Conveying the Desired Address Type . . . . . . . . . . . 7 4. Usage example . . . . . . . . . . . . . . . . . . . . . . . . 8 - 5. Backwards Compatibility Considerations . . . . . . . . . . . 10 - 5.1. Applications . . . . . . . . . . . . . . . . . . . . . . 10 - 5.2. IP Stack in the Mobile Host . . . . . . . . . . . . . . . 10 - 5.3. Network Infrastructure . . . . . . . . . . . . . . . . . 10 - 5.4. Merging this work with RFC5014 . . . . . . . . . . . . . 11 - 6. Summary of New Definitions . . . . . . . . . . . . . . . . . 11 - 6.1. New APIs . . . . . . . . . . . . . . . . . . . . . . . . 11 - 6.2. New Flags . . . . . . . . . . . . . . . . . . . . . . . . 12 - 7. Security Considerations . . . . . . . . . . . . . . . . . . . 13 - 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13 - 9. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 13 - 10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 13 - 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 13 - 11.1. Normative References . . . . . . . . . . . . . . . . . . 13 - 11.2. Informative References . . . . . . . . . . . . . . . . . 14 - Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 15 + 4.1. Pseudo-code example . . . . . . . . . . . . . . . . . . . 8 + 4.2. Message Flow example . . . . . . . . . . . . . . . . . . 10 + 5. Backwards Compatibility Considerations . . . . . . . . . . . 11 + 5.1. Applications . . . . . . . . . . . . . . . . . . . . . . 11 + 5.2. IP Stack in the Mobile Host . . . . . . . . . . . . . . . 12 + 5.3. Network Infrastructure . . . . . . . . . . . . . . . . . 12 + 5.4. Merging this work with RFC5014 . . . . . . . . . . . . . 12 + 6. Summary of New Definitions . . . . . . . . . . . . . . . . . 13 + 6.1. New APIs . . . . . . . . . . . . . . . . . . . . . . . . 13 + 6.2. New Flags . . . . . . . . . . . . . . . . . . . . . . . . 13 + 7. Security Considerations . . . . . . . . . . . . . . . . . . . 14 + 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14 + 9. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 14 + 10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 14 + 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 14 + 11.1. Normative References . . . . . . . . . . . . . . . . . . 15 + 11.2. Informative References . . . . . . . . . . . . . . . . . 15 + Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 16 1. Introduction In the context of Mobile IP [RFC5563][RFC6275][RFC5213][RFC5944], the following two attributes are defined for IP service provided to mobile hosts: - IP session continuity: The ability to maintain an ongoing IP session - by keeping the same local end-point IP address throughout the session - despite the mobile host changing its point of attachment within the - IP network topology. The IP address of the host may change between - two independent IP sessions, but that does not jeopardize its IP - session continuity. IP session continuity is essential for mobile - hosts to maintain ongoing flows without any interruption. + Session continuity: The ability to maintain an ongoing transport + interaction by keeping the same local end-point IP address throughout + the life-time of the IP socket despite the mobile host changing its + point of attachment within the IP network topology. The IP address + of the host may change after closing the IP socket and before opening + a new one, but that does not jeopardize the ability of applications + 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 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. - The IP address may be published in a long-term registry (e.g., DNS), - and is made available for serving incoming (e.g., TCP) connections. - IP address reachability is essential for mobile hosts to use - specific/published IP addresses. + independent sessions, and even in the absence of any session. The IP + address may be published in a long-term registry (e.g., DNS), and is + made available for serving incoming (e.g., TCP) connections. IP + address reachability is essential for mobile hosts to use specific/ + 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 protocols (e.g., 3GPP, 3GPP2, WIMAX) ensure that any mobile host attached to the compliant networks can enjoy these benefits. Any 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. It should be noted that in reality not every application may need these benefits. IP address reachability is required for applications running as servers (e.g., a web server running on the mobile host). 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. 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 - Mobile IP incurs some cost. Mobile IP protocol forces the mobile - host's IP traffic to traverse a centrally-located router (Home Agent, - HA), which incurs additional transmission latency and use of - additional network resources, adds to the network CAPEX and OPEX, and - decreases the reliability of the network due to the introduction of a - single point of failure [RFC7333]. Therefore, IP session continuity - and IP address reachability SHOULD be provided only when necessary. + Achieving session continuity and IP address reachability with Mobile + IP incurs some cost. Mobile IP protocol forces the mobile host's IP + traffic to traverse a centrally-located router (Home Agent, HA), + which incurs additional transmission latency and use of additional + network resources, adds to the network CAPEX and OPEX, and decreases + the reliability of the network due to the introduction of a single + point of failure [RFC7333]. Therefore, session continuity and IP + address reachability SHOULD be provided only when necessary. Furthermore, when an application needs session continuity, it may be able to satisfy that need by using a solution above the IP layer, such as MPTCP [RFC6824], SIP mobility [RFC3261], or an application- layer mobility solution. These higher-layer solutions are not 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. But, if Mobile IP is being applied to the mobile host, the higher- layer protocols are rendered useless because their operation is 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), the higher-layer protocols never detect the IP- layer change and never engage in mobility management. This document proposes a solution for applications running on mobile - hosts to indicate whether they need IP session continuity or IP - address reachability. The network protocol stack on the mobile host, - in conjunction with the network infrastructure, provides the required - type of IP service. It is for the benefit of both the users and the + hosts to indicate whether they need session continuity or IP address + reachability. The network protocol stack on the mobile host, in + conjunction with the network infrastructure, provides the required + 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 is absolutely necessary. It is expected that applications and networks compliant with this specification will utilize this solution to use network resources more efficiently. 2. Notational Conventions The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119]. @@ -169,66 +173,69 @@ - Fixed IP Address 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 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- attachment to another (with a different IP prefix) while it is 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-lasting IP Address 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 - guaranteed to be valid even after the mobile host had moved from one - point-of-attachment to another (with a different IP prefix). + valid throughout the life-time of the socket(s) for which it was + requested. It is guaranteed to be valid even after the mobile host + had moved from one point-of-attachment to another (with a different + IP prefix). 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 - This type of IP address does not provide IP session continuity nor IP - address reachability. The IP address is created from an IP prefix - that is obtained from the serving IP gateway and is not maintained - across gateway changes. In other words, the IP prefix may be - released and replaced by a new one 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. + This type of IP address has no guarantee to exist after a mobile host + moves from one point-of-attachment to another, and therefore, no + session continuity nor IP address reachability are provided. The IP + address is created from an IP prefix that is obtained from the + serving IP gateway and is not maintained across gateway changes. In + other words, the IP prefix may be released and replaced by a new one + 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 In some cases, the network cannot guarantee the validity of the - provided IP prefix throughout the duration of the IP session, but can - provide a limited graceful period of time in which both the original - IP prefix and a new one are valid. This enables the application some - flexibility in the transition from the existing source IP address to - the new one. + provided IP prefix throughout the duration of the opened socket, but + can provide a limited graceful period of time in which both the + original IP prefix and a new one are valid. This enables the + application some flexibility in the transition from the existing + source IP address to the new one. This gracefulness is still better than the non-persistence type of address for applications that can handle a change in their source IP address but require that extra flexibility. Applications running as servers at a published IP address require a Fixed IP Address. Long-standing applications (e.g., an SSH session) may also require this type of address. Enterprise applications that connect to an enterprise network via virtual LAN require a Fixed IP 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. - 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 though they could very well use Fixed or Session-lasting IP Addresses, the transmission latency would be minimized when a Non- persistent IP Addresses are used. Applications that can tolerate a short interruption in connectivity can use the Graceful-replacement IP addresses. For example, a streaming client that has buffering capabilities. 3.2. Granularity of Selection @@ -257,24 +264,24 @@ the operation fails, the IP stack SHALL fail the associated socket request and return an error. If successful, a Session-lasting IP Address gets configured on the mobile host. If another socket 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 using the same configured IP address is closed, the IP address may be released or kept for future applications that may be launched and require a Session-lasting IP address. 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 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 request new ones. It supports both alternatives (and any combination). 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 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 host itself, the network operator, or the system architecture @@ -296,31 +303,31 @@ source address selection with the IPV6_ADDR_PREFERENCE option at the IPPROTO_IPV6 level. This option is used with setsockopt() and getsockopt() calls to set/get address selection preferences. 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 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 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 service. The new getsc() API will return an IPv6 address that is associated with the desired session continuity service and with status information indicating whether or not the desired service was provided. An application that wishes to secure a desired service will call getsc() with the service type definition and a place to contain the 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 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 the host does not already have an IPv6 prefix of that specific type, it MUST request one from the network. 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 configuration). On the other hand, acquiring a new IP prefix from @@ -331,28 +338,30 @@ preconfigured source IP address (if exists) or to request a new IPv6 prefix from the current serving network and configure a new IP address. This new flag is added to the set of flags in the IPV6_ADDR_PREFERENCES option at the IPPROTO_IPV6 level. It is used in setsockopt() to set the desired behavior. 4. Usage example +4.1. Pseudo-code example + The following example shows pseudo-code for creating a Stream socket (TCP) with a Session-Lasting source IP address: #include #include // Socket information - int s ; // Socket id + int s ; // socket id // Source information (for secsc() and bind()) sockaddr_in6 sourceInfo // my address and port for bind() in6_addr sourceAddress // will contain the provisioned // source IP address uint8_t sc_type = IPV6_REQUIRE_SESSION_LASTING_IP ; // For requesting a Session-Lasting // source IP address // Destination information (for connect()) @@ -414,20 +422,93 @@ // application code that does not use Session-lasting IP // address. The application may either connect without // the desired Session-lasting service, or close the // socket... } // if setsc() failed } // if socket was created successfully // 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 Backwards compatibility support is REQUIRED by the following 3 types of entities: - The Applications on the mobile host - The IP stack in the mobile host - The network infrastructure