--- 1/draft-ietf-dmm-ondemand-mobility-15.txt 2019-02-08 04:13:23.501090635 -0800 +++ 2/draft-ietf-dmm-ondemand-mobility-16.txt 2019-02-08 04:13:23.537091492 -0800 @@ -1,137 +1,142 @@ DMM Working Group A. Yegin Internet-Draft Actility Intended status: Informational D. Moses -Expires: January 27, 2019 Intel +Expires: August 12, 2019 Intel K. Kweon J. Lee J. Park Samsung S. Jeon Sungkyunkwan University - July 26, 2018 + February 8, 2019 On Demand Mobility Management - draft-ietf-dmm-ondemand-mobility-15 + draft-ietf-dmm-ondemand-mobility-16 Abstract 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 session continuity and IP address reachability on a per- - socket basis. + on the host yields inefficiencies, as described in section 4 of + [RFC7333]. This document defines a new concep of enabling + applications to influence the network's mobility services (session + continuity and/or IP address reachability) on a per-Socket basis, and + suggests extensions to the networking stack's API to accomodate this + concept. 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 January 27, 2019. + This Internet-Draft will expire on August 12, 2019. Copyright Notice - Copyright (c) 2018 IETF Trust and the persons identified as the + Copyright (c) 2019 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 carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must 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 + 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Notational Conventions . . . . . . . . . . . . . . . . . . . 4 3. Solution . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 3.1. Types of IP Addresses . . . . . . . . . . . . . . . . . . 4 - 3.2. Granularity of Selection . . . . . . . . . . . . . . . . 6 - 3.3. On Demand Nature . . . . . . . . . . . . . . . . . . . . 6 - 3.4. Conveying the Desired Address Type . . . . . . . . . . . 7 - 4. Usage example . . . . . . . . . . . . . . . . . . . . . . . . 8 - 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 + 3.1. High-level Description . . . . . . . . . . . . . . . . . 4 + 3.2. Types of IP Addresses . . . . . . . . . . . . . . . . . . 5 + 3.3. Granularity of Selection . . . . . . . . . . . . . . . . 7 + 3.4. On Demand Nature . . . . . . . . . . . . . . . . . . . . 7 + 3.5. Conveying the Desired Address Type . . . . . . . . . . . 8 + 4. Usage example . . . . . . . . . . . . . . . . . . . . . . . . 9 + 4.1. Pseudo-code example . . . . . . . . . . . . . . . . . . . 9 + 4.2. Message Flow example . . . . . . . . . . . . . . . . . . 11 + 5. Backwards Compatibility Considerations . . . . . . . . . . . 12 + 5.1. Applications . . . . . . . . . . . . . . . . . . . . . . 12 + 5.2. IP Stack in the Mobile Host . . . . . . . . . . . . . . . 13 + 5.3. Network Infrastructure . . . . . . . . . . . . . . . . . 13 + 5.4. Merging this work with RFC5014 . . . . . . . . . . . . . 13 + 6. Summary of New Definitions . . . . . . . . . . . . . . . . . 14 + 6.1. New APIs . . . . . . . . . . . . . . . . . . . . . . . . 14 + 6.2. New Flags . . . . . . . . . . . . . . . . . . . . . . . . 14 + 7. Security Considerations . . . . . . . . . . . . . . . . . . . 15 + 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15 + 9. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 15 + 10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 15 + 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 15 + 11.1. Normative References . . . . . . . . . . . . . . . . . . 16 + 11.2. Informative References . . . . . . . . . . . . . . . . . 16 + Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 17 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: - 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. + - Session Continuity - 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 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. + 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 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 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 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, session - continuity is not required for all types of applications either. - Applications performing brief communication (e.g., ping) can survive - without having session continuity support. + 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, session continuity is not required + for all types of applications either. Applications performing brief + communication (e.g., text messaging) can survive without having + session continuity support. 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. @@ -142,38 +147,70 @@ 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 session continuity or IP address + hosts to indicate when establishing the network connection ('on + demand') 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]. + "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and + "OPTIONAL" in this document are to be interpreted as described in BCP + 14 , [RFC2119] [RFC8174] when, they appear in all capitals, as shown + here. 3. Solution -3.1. Types of IP Addresses +3.1. High-level Description + + Enabling applications to indicate their mobility service requirements + e.g. session continuity and/or IP address reachability, comprises the + following steps: + + - The application indicates to the network stack (local to the mobile + host) the desired mobility service. + + - The network stack assigns a source IP address based on an IP prefix + with the desired services that was previously provided by the + network. If such an IP prefix is not available, the network stack + performs the additional steps below. + + - The network stack sends a request to the network for a new source + IP prefix that is associated with the desired mobility service. + + - The network responds with the suitable allocated source IP prefix + (or responds with a failure indication). + + - If the suitable source IP prefix was allocates, the network stack + constructs a source IP address and provides it to the application. + + This document specifies the new address types (associated with + mobility services) and details the interaction between the + applications and the network stack steps. It uses the Socket + interface as an example for an API between applications and the + network stack. Other steps are outside the scope of this document. + +3.2. Types of IP Addresses Four types of IP addresses are defined with respect to mobility management. - 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- @@ -231,101 +268,101 @@ 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 +3.3. Granularity of Selection IP address type selection is made on a per-socket granularity. Different parts of the same application may have different needs. For example, the control-plane of an application may require a Fixed IP Address in order to stay reachable, whereas the data-plane of the same application may be satisfied with a Session-lasting IP Address. -3.3. On Demand Nature +3.4. On Demand Nature At any point in time, a mobile host may have a combination of IP - addresses configured. Zero or more Non-persistent, zero or more - Session-lasting, zero or more Fixed and zero or more Graceful- + addresses configured. Zero or more Fixed, zero or more Session- + lasting, zero or more Non-persistent and zero or more Graceful- Replacement IP addresses may be configured by the IP stack of the host. The combination may be as a result of the host policy, application demand, or a mix of the two. When an application requires a specific type of IP address and such an address is not already configured on the host, the IP stack SHALL attempt to configure one. For example, a host may not always have a Session-lasting IP address available. When an application requests one, the IP stack SHALL make an attempt to configure one by issuing a - request to the network (see Section 3.4 below for more details). If + request to the network (see Section 3.5 below for more details). If 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 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 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). + 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 standard: - The initial set of IP addresses configured on the host at boot time. - Permission to grant various types of IP addresses to a requesting application. - Determination of a default address type when an application does not make any explicit indication, whether it already supports the required API or it is just a legacy application. -3.4. Conveying the Desired Address Type +3.5. Conveying the Desired Address Type [RFC5014] introduced the ability of applications to influence the 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 - setsc() which allows applications to express their desired type of session continuity - service. The new getsc() API will return an IPv6 address that is + service. The new setsc() 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 + setsc() 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). 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 @@ -349,21 +386,21 @@ 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 - // Source information (for secsc() and bind()) + // Source information (for setsc() 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()) sockaddr_in6 serverInfo ; // server info for connect() @@ -425,26 +462,26 @@ // 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 + achieving On-Demand 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. + - Applications requiring different types of On-Demand 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. @@ -508,25 +545,25 @@ of entities: - The Applications on the mobile host - The IP stack in the mobile host - The network infrastructure 5.1. Applications - Legacy applications that do not support the OnDemand functionality + Legacy applications that do not support the On-Demand functionality will use the legacy API and will not be able to take advantage of the On-Demand Mobility feature. - Applications using the new OnDemand functionality MUST be aware that + Applications using the new On-Demand functionality MUST be aware that they may be executed in legacy environments that do not support it. Such environments may include a legacy IP stack on the mobile host, legacy network infrastructure, or both. In either case, the API will return an error code and the invoking applications may just give up and use legacy calls. 5.2. IP Stack in the Mobile Host New IP stacks MUST continue to support all legacy operations. If an application does not use On-Demand functionality, the IP stack MUST @@ -552,26 +589,25 @@ 5.4. Merging this work with RFC5014 [RFC5014] defines new flags that may be used with setsockopt() to influence source IP address selection for a socket. The list of flags include: source home address, care-of address, temporary address, public address CGA (Cryptographically Created Address) and non-CGA. When applications require session continuity service and use setsc() and bind(), they SHOULD NOT set the flags specified in [RFC5014]. - However, if an application sets a specific option using setsockopt() - with one of the flags specified in [RFC5014] and also selects a - source IP address using setsc() and bind() the IP address that was - generated by setsc() and bound using bind() will be the one used by - traffic generated using that socket and options set by setsockopt() - will be ignored. + However, if an application erroneously performs a combination of (1) + Use setsockopt() to set a specific option (using one of the flags + specified in [RFC5014]) and (2) Selects a source IP address type + using setsc() and bind(), the IP stack will fulfill the request + specified by (2) and ignore the flags set by (1). If bind() was not invoked after setsc() by the application, the IP address generated by setsc() will not be used and traffic generated by the socket will use a source IP address that complies with the options selected by setsockopt(). 6. Summary of New Definitions 6.1. New APIs @@ -666,20 +702,24 @@ [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC5014] Nordmark, E., Chakrabarti, S., and J. Laganier, "IPv6 Socket API for Source Address Selection", RFC 5014, DOI 10.17487/RFC5014, September 2007, . + [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC + 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, + May 2017, . + 11.2. Informative References [I-D.sijeon-dmm-use-cases-api-source] Jeon, S., Figueiredo, S., Kim, Y., and J. Kaippallimalil, "Use Cases and API Extension for Source IP Address Selection", draft-sijeon-dmm-use-cases-api-source-07 (work in progress), September 2017. [RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, A., Peterson, J., Sparks, R., Handley, M., and E.