--- 1/draft-ietf-dmm-ondemand-mobility-08.txt 2016-12-12 06:13:14.659787021 -0800 +++ 2/draft-ietf-dmm-ondemand-mobility-09.txt 2016-12-12 06:13:14.687787703 -0800 @@ -1,25 +1,25 @@ DMM Working Group A. Yegin Internet-Draft Actility Intended status: Informational D. Moses -Expires: June 1, 2017 Intel +Expires: June 15, 2017 Intel K. Kweon J. Lee J. Park Samsung S. Jeon Sungkyunkwan University - November 28, 2016 + December 12, 2016 On Demand Mobility Management - draft-ietf-dmm-ondemand-mobility-08 + draft-ietf-dmm-ondemand-mobility-09 Abstract Applications differ with respect to whether they need IP 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 in selectively providing IP session continuity and IP address reachability on a per- socket basis. @@ -32,21 +32,21 @@ 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 http://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 June 1, 2017. + This Internet-Draft will expire on June 15, 2017. Copyright Notice Copyright (c) 2016 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 (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents @@ -65,21 +65,21 @@ 3.2. Granularity of Selection . . . . . . . . . . . . . . . . 5 3.3. On Demand Nature . . . . . . . . . . . . . . . . . . . . 5 3.4. Conveying the Selection . . . . . . . . . . . . . . . . . 6 4. Backwards Compatibility Considerations . . . . . . . . . . . 9 4.1. Applications . . . . . . . . . . . . . . . . . . . . . . 9 4.2. IP Stack in the Mobile Host . . . . . . . . . . . . . . . 9 4.3. Network Infrastructure . . . . . . . . . . . . . . . . . 10 5. Summary of New Definitions . . . . . . . . . . . . . . . . . 10 6. Security Considerations . . . . . . . . . . . . . . . . . . . 10 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10 - 8. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 10 + 8. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 11 9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 11 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 11 10.1. Normative References . . . . . . . . . . . . . . . . . . 11 10.2. Informative References . . . . . . . . . . . . . . . . . 11 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 12 1. Introduction In the context of Mobile IP [RFC5563][RFC6275][RFC5213][RFC5944], following two attributes are defined for the IP service provided to @@ -128,24 +128,24 @@ and IP address reachability should be be provided only when needed. 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. Those 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, those higher- layer protocols are rendered useless because their operation is - inhibited by the Mobile IP. Since Mobile IP ensures 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. + inhibited by the 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 the applications running on the mobile host 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, would provide the required type of IP 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. So it is expected that applications and networks compliant with this specification would utilize this solution to use network resources more efficiently. @@ -165,29 +165,29 @@ - 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 subnet or IP prefix) while it is connected. - Fixed IP address are required by applications that need both IP + Fixed IP addresses are required by applications that need both IP session continuity and IP address reachability. - Session-lasting IP Address A session-lasting IP address is an address with a guarantee to be - valid through-out 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 subnet or IP + 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 subnet or IP prefix). Session-lasting IP addresses are required by applications that need IP session continuity but do not need IP address reachability. - Non-persistent IP Address This type of IP address provides neither IP session continuity nor IP address reachability. The IP address is obtained from the serving IP gateway and it is not maintained across gateway changes. In other words, the IP address may be released and replaced by a new IP @@ -196,185 +196,192 @@ 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- lasting IP Addresses. For example: Web browsers. - Applications with very short IP sessions, such as DNS client and + Applications with very short IP sessions, such as DNS clients and instant messengers, can utilize Non-persistent IP Addresses. Even - though they could very well use a Fixed of Session-lasting IP + though they could very well use Fixed or Session-lasting IP Addresses, the transmission latency would be minimized when a Non- - persistent IP Address is used. + persistent IP Addresses are used. The network creates the desired guarantee (Fixed, Session-lasting or - Non-persistent) by either assigning an IP address (as part of a - stateful IP address generation), or by assigning the address prefix - (as part of a stateless address generation process). + Non-persistent) by either assigning the address prefix (as part of a + stateless address generation process), or by assigning an IP address + (as part of a stateful IP address generation). + + The exact mechanism of prefix or address assignment is outside the + scope of this specification. 3.2. Granularity of Selection The IP address type selection is made on a per-socket granularity. Different parts of the same application may have different needs. For example, control-plane of an application may require a Fixed IP Address in order to stay reachable, whereas data-plane of the same application may be satisfied with a Session-lasting IP Address. 3.3. 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, and zero or more Fixed IP addresses may be configured on 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 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. In case an application - requests one, the IP stack shall make an attempt to configure one by - issuing a request to the network. If the operation fails, the IP - stack shall fail the associated socket request. 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 requested 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. + 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. If the operation fails, the IP stack shall + fail the associated socket request. 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 (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 out of the scope of this specification to define + session). It is outside the scope of this specification to define criteria for selecting to use available addresses or choose to request new ones. It supports both alternatives (and any combination). - It is outside of the scope of this specification to define how the - host requests a specific type of address (Fixed, Session-lasting or - Non-persistent) and how the network indicates the type of address in - its advertisement of addresses (or in its reply to an address + It is outside the scope of this specification to define how the host + requests a specific type of address (Fixed, Session-lasting or Non- + persistent) and how the network indicates the type of address in its + advertisement of IP prefixes or addresses (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 the boot + - 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 Selection The selection of the address type is conveyed from the applications - to the IP stack in a way to influence the source address selection + to the IP stack in oredr to influence the source address selection algorithm [RFC6724]. The current source address selection algorithm operates on the - available set of IP addresses when selecting an address. According - to the proposed solution, if the requested type IP address is not + available set of IP addresses, when selecting an address. According + to the proposed solution, if the requested IP address type is not available at the time of the request, the IP stack shall make an attempt to configure one such IP address. The selected IP address shall be compliant with the requested IP address type, whether it is selected among available addresses or dynamically configured. In the absence of a matching type (because it is not available and not configurable on demand), the source address selection algorithm shall return an empty set. A Socket API-based interface for enabling applications to influence the source address selection algorithm is described in [RFC5014]. That specification defines IPV6_ADDR_PREFERENCES option at the IPPROTO_IPV6 level. That option can be used with setsockopt() and getsockopt() calls to set and get address selection preferences. Furthermore, that RFC also specifies two flags that relate to IP mobility management: IPV6_PREFER_SRC_HOME and IPV6_PREFER_SRC_COA. These flags are used for influencing the source address selection to prefer either a Home Address or a Care-of Address. Unfortunately, these flags do not satisfy the aforementioned needs - due to the following reasons, therefore new flags are proposed in - this document: + due to the following reasons: - Current flags indicate a "preference" whereas there is a need for indicating "requirement". Source address selection algorithm does not have to produce an IP address compliant with the "preference" , but it has to produce an IP address compliant with the "requirement". - Current flags influence the selection made among available IP addresses. The new flags force the IP stack to configure a compliant IP address if none is available at the time of the request. - The Home vs. Care-of Address distinction is not sufficient to capture the three different types of IP addresses described in Section 2.1. The following new flags are defined in this document and they shall - be used with Socket API in compliance with the [RFC5014]: + be used with Socket API in compliance with [RFC5014]: IPV6_REQUIRE_FIXED_IP /* Require a Fixed IP address as source */ IPV6_REQUIRE_SESSION_LASTING_IP /* Require a Session-lasting IP address as source */ IPV6_REQUIRE_NON-PERSISTENT_IP /* Require a Non-persistent IP address as source */ Only one of these flags may be set on the same socket. If an application attempts to set more than one flag, the most recent setting will be the one in effect. - When any of these new flags is used, then the IPV6_PREFER_SRC_HOME - and IPV6_PREFER_SRC_COA flags, if used, shall be ignored. + When any of these new flags is used, the IPV6_PREFER_SRC_HOME and + IPV6_PREFER_SRC_COA flags, if used, shall be ignored. These new flags are used with setsockopt()/getsockopt(), getaddrinfo(), and inet6_is_srcaddr() functions [RFC5014]. Similar - with the setsockopt()/getsockopt() calls, getaddrinfo() call shall - also trigger configuration of the required type IP address, if one is + to the setsockopt()/getsockopt() calls, the getaddrinfo() call shall + also trigger configuration of the required IP address type, if one is not already available. When the new flags are used with getaddrinfo() and the triggered configuration fails, the getaddrinfo() call shall ignore that failure (i.e., not return an error code to indicate that failure). Only the setsockopt() shall - return an error when configuration of the requested type IP address + return an error when configuration of the requested IP address type fails. - When the IP stack is required to assign a source IP address of a - specified type, it can perform one of the following: It can assigned - a preconfigured address (if one exists) or request a new one from the - network. Using an existing address is instantaneous but might yield - a less optimal route (if a hand-off event occurred since its - configuration), on the other hand, acquiring a new IP address from - the network may take some time (due to signaling exchange with the - network). + When the IP stack is required to use a source IP address of a + specified type, it can perform one of the following: It can use an + existing address (if it has one), or it can create a new one from an + existing prefix of the desired type. If the host does not already + have an IPv6 prefix of the specific type, it can 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 since its + configuration), on the other hand, acquiring a new IP prefix from the + network may take some time (due to signaling exchange with the + network) and may fail due to network policies. An additional new flag - ON_NET flag - enables the application to direct the IP stack whether to use a preconfigured source IP address - (if exists) or to request a new one from the current serving network: + (if exists) or to request a new IPv6 prefix from the current serving + network and configure a new IP address: IPV6_REQUIRE_SRC_ON_NET /* Set IP stack address allocation behavior */ - If set, the IP stack will request a new IP address of the desired - type from the current serving network. If reset, the IP stack will - use a preconfigured one if exists. If there is no preconfigured IP - address of the desired type, the IP stack will request a new one from - the current serving network (regardless of whether this flag is set - or reset). + If set, the IP stack will request a new IPv6 prefix of the desired + type from the current serving network and configure a new source IP + address. If reset, the IP stack will use a preconfigured one if + exists. If there is no preconfigured IP address of the desired type, + the IP stack will request a IPv6 prefix from the current serving + network (regardless of whether this flag is set or not). The ON_NET flag must be used together with one of the 3 flags defined above. If ON_NET flag is used without any of these flags, it must be ignored. If the ON_NET flag is not used, the IP stack is free to either use an existing IP address (if preconfigured) or access the network to configure a new one (the decision is left to implementation). The following new error codes are also defined in the document and will be used in the Socket API in compliance with [RFC5014]. @@ -396,39 +403,40 @@ - The network infrastructure 4.1. Applications Legacy applications that do not support the new flags will use the legacy API to the IP stack and will not enjoy On-Demand Mobility feature. Applications using the new flags must be aware that they may be - executed in environments that do not support On-Demand Mobility + executed in environments that do not support the On-Demand Mobility feature. Such environments may include legacy IP stack in the mobile host, legacy network infrastructure, or both. In either case, the API will return an error code and the invoking applications must - respond with using legacy calls without On-Demand Mobility feature. + respond with using legacy calls without the On-Demand Mobility + feature. 4.2. IP Stack in the Mobile Host New IP stacks must continue to support all legacy operations. If an application does not use On-Demand Mobility feature, the IP stack must respond in a legacy manner. If the network infrastructure supports On-Demand Mobility feature, the IP stack should follow the application request: If the application requests a specific address type, the stack should forward this request to the network. If the application does not request an address type, the IP stack must not request an address type and leave it to the network's default behavior to choose the - type of the allocated IP address. If an IP address was already + type of the allocated IP prefix. If an IP prefix was already allocated to the host, the IP stack uses it and may not request a new one from the network. 4.3. Network Infrastructure The network infrastructure may or may not support the On-Demand Mobility feature. How the IP stack on the host and the network infrastructure behave in case of a compatibility issue is outside the scope of this API specification. @@ -476,22 +484,23 @@ Younghan Kim Soongsil University, Korea Email: younghak@ssu.ac.kr John Kaippallimalil Huawei, USA Email: john.kaippallimalil@huawei.com 9. Acknowledgements - We would like to thank Alexandru Petrescu, Jouni Korhonen, and Sri - Gundavelli for their valuable comments and suggestions on this work. + We would like to thank Alexandru Petrescu, Jouni Korhonen, Sri + Gundavelli, and Lorenzo Colitti for their valuable comments and + suggestions on this work. 10. References 10.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, .