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Checking references for intended status: Informational ---------------------------------------------------------------------------- -- Obsolete informational reference (is this intentional?): RFC 6824 (Obsoleted by RFC 8684) Summary: 1 error (**), 0 flaws (~~), 2 warnings (==), 3 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 DMM Working Group A. Yegin 3 Internet-Draft Actility 4 Intended status: Informational D. Moses 5 Expires: August 12, 2019 Intel 6 K. Kweon 7 J. Lee 8 J. Park 9 Samsung 10 S. Jeon 11 Sungkyunkwan University 12 February 8, 2019 14 On Demand Mobility Management 15 draft-ietf-dmm-ondemand-mobility-16 17 Abstract 19 Applications differ with respect to whether they need session 20 continuity and/or IP address reachability. The network providing the 21 same type of service to any mobile host and any application running 22 on the host yields inefficiencies, as described in section 4 of 23 [RFC7333]. This document defines a new concep of enabling 24 applications to influence the network's mobility services (session 25 continuity and/or IP address reachability) on a per-Socket basis, and 26 suggests extensions to the networking stack's API to accomodate this 27 concept. 29 Status of This Memo 31 This Internet-Draft is submitted in full conformance with the 32 provisions of BCP 78 and BCP 79. 34 Internet-Drafts are working documents of the Internet Engineering 35 Task Force (IETF). Note that other groups may also distribute 36 working documents as Internet-Drafts. The list of current Internet- 37 Drafts is at https://datatracker.ietf.org/drafts/current/. 39 Internet-Drafts are draft documents valid for a maximum of six months 40 and may be updated, replaced, or obsoleted by other documents at any 41 time. It is inappropriate to use Internet-Drafts as reference 42 material or to cite them other than as "work in progress." 44 This Internet-Draft will expire on August 12, 2019. 46 Copyright Notice 48 Copyright (c) 2019 IETF Trust and the persons identified as the 49 document authors. All rights reserved. 51 This document is subject to BCP 78 and the IETF Trust's Legal 52 Provisions Relating to IETF Documents 53 (https://trustee.ietf.org/license-info) in effect on the date of 54 publication of this document. Please review these documents 55 carefully, as they describe your rights and restrictions with respect 56 to this document. Code Components extracted from this document must 57 include Simplified BSD License text as described in Section 4.e of 58 the Trust Legal Provisions and are provided without warranty as 59 described in the Simplified BSD License. 61 Table of Contents 63 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 64 2. Notational Conventions . . . . . . . . . . . . . . . . . . . 4 65 3. Solution . . . . . . . . . . . . . . . . . . . . . . . . . . 4 66 3.1. High-level Description . . . . . . . . . . . . . . . . . 4 67 3.2. Types of IP Addresses . . . . . . . . . . . . . . . . . . 5 68 3.3. Granularity of Selection . . . . . . . . . . . . . . . . 7 69 3.4. On Demand Nature . . . . . . . . . . . . . . . . . . . . 7 70 3.5. Conveying the Desired Address Type . . . . . . . . . . . 8 71 4. Usage example . . . . . . . . . . . . . . . . . . . . . . . . 9 72 4.1. Pseudo-code example . . . . . . . . . . . . . . . . . . . 9 73 4.2. Message Flow example . . . . . . . . . . . . . . . . . . 11 74 5. Backwards Compatibility Considerations . . . . . . . . . . . 12 75 5.1. Applications . . . . . . . . . . . . . . . . . . . . . . 12 76 5.2. IP Stack in the Mobile Host . . . . . . . . . . . . . . . 13 77 5.3. Network Infrastructure . . . . . . . . . . . . . . . . . 13 78 5.4. Merging this work with RFC5014 . . . . . . . . . . . . . 13 79 6. Summary of New Definitions . . . . . . . . . . . . . . . . . 14 80 6.1. New APIs . . . . . . . . . . . . . . . . . . . . . . . . 14 81 6.2. New Flags . . . . . . . . . . . . . . . . . . . . . . . . 14 82 7. Security Considerations . . . . . . . . . . . . . . . . . . . 15 83 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15 84 9. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 15 85 10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 15 86 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 15 87 11.1. Normative References . . . . . . . . . . . . . . . . . . 16 88 11.2. Informative References . . . . . . . . . . . . . . . . . 16 89 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 17 91 1. Introduction 93 In the context of Mobile IP [RFC5563][RFC6275][RFC5213][RFC5944], the 94 following two attributes are defined for IP service provided to 95 mobile hosts: 97 - Session Continuity 99 The ability to maintain an ongoing transport interaction by keeping 100 the same local end-point IP address throughout the life-time of the 101 IP socket despite the mobile host changing its point of attachment 102 within the IP network topology. The IP address of the host may 103 change after closing the IP socket and before opening a new one, but 104 that does not jeopardize the ability of applications using these IP 105 sockets to work flawlessly. Session continuity is essential for 106 mobile hosts to maintain ongoing flows without any interruption. 108 - IP Address Reachability 110 The ability to maintain the same IP address for an extended period of 111 time. The IP address stays the same across independent sessions, and 112 even in the absence of any session. The IP address may be published 113 in a long-term registry (e.g., DNS), and is made available for 114 serving incoming (e.g., TCP) connections. IP address reachability is 115 essential for mobile hosts to use specific/published IP addresses. 117 Mobile IP is designed to provide both session continuity and IP 118 address reachability to mobile hosts. Architectures utilizing these 119 protocols (e.g., 3GPP, 3GPP2, WIMAX) ensure that any mobile host 120 attached to the compliant networks can enjoy these benefits. Any 121 application running on these mobile hosts is subjected to the same 122 treatment with respect to session continuity and IP address 123 reachability. 125 In reality not every application may need these benefits. IP address 126 reachability is required for applications running as servers (e.g., a 127 web server running on the mobile host). But, a typical client 128 application (e.g., web browser) does not necessarily require IP 129 address reachability. Similarly, session continuity is not required 130 for all types of applications either. Applications performing brief 131 communication (e.g., text messaging) can survive without having 132 session continuity support. 134 Achieving session continuity and IP address reachability with Mobile 135 IP incurs some cost. Mobile IP protocol forces the mobile host's IP 136 traffic to traverse a centrally-located router (Home Agent, HA), 137 which incurs additional transmission latency and use of additional 138 network resources, adds to the network CAPEX and OPEX, and decreases 139 the reliability of the network due to the introduction of a single 140 point of failure [RFC7333]. Therefore, session continuity and IP 141 address reachability SHOULD be provided only when necessary. 143 Furthermore, when an application needs session continuity, it may be 144 able to satisfy that need by using a solution above the IP layer, 145 such as MPTCP [RFC6824], SIP mobility [RFC3261], or an application- 146 layer mobility solution. These higher-layer solutions are not 147 subject to the same issues that arise with the use of Mobile IP since 148 they can utilize the most direct data path between the end-points. 149 But, if Mobile IP is being applied to the mobile host, the higher- 150 layer protocols are rendered useless because their operation is 151 inhibited by Mobile IP. Since Mobile IP ensures that the IP address 152 of the mobile host remains fixed (despite the location and movement 153 of the mobile host), the higher-layer protocols never detect the IP- 154 layer change and never engage in mobility management. 156 This document proposes a solution for applications running on mobile 157 hosts to indicate when establishing the network connection ('on 158 demand') whether they need session continuity or IP address 159 reachability. The network protocol stack on the mobile host, in 160 conjunction with the network infrastructure, provides the required 161 type of service. It is for the benefit of both the users and the 162 network operators not to engage an extra level of service unless it 163 is absolutely necessary. It is expected that applications and 164 networks compliant with this specification will utilize this solution 165 to use network resources more efficiently. 167 2. Notational Conventions 169 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 170 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 171 "OPTIONAL" in this document are to be interpreted as described in BCP 172 14 , [RFC2119] [RFC8174] when, they appear in all capitals, as shown 173 here. 175 3. Solution 177 3.1. High-level Description 179 Enabling applications to indicate their mobility service requirements 180 e.g. session continuity and/or IP address reachability, comprises the 181 following steps: 183 - The application indicates to the network stack (local to the mobile 184 host) the desired mobility service. 186 - The network stack assigns a source IP address based on an IP prefix 187 with the desired services that was previously provided by the 188 network. If such an IP prefix is not available, the network stack 189 performs the additional steps below. 191 - The network stack sends a request to the network for a new source 192 IP prefix that is associated with the desired mobility service. 194 - The network responds with the suitable allocated source IP prefix 195 (or responds with a failure indication). 197 - If the suitable source IP prefix was allocates, the network stack 198 constructs a source IP address and provides it to the application. 200 This document specifies the new address types (associated with 201 mobility services) and details the interaction between the 202 applications and the network stack steps. It uses the Socket 203 interface as an example for an API between applications and the 204 network stack. Other steps are outside the scope of this document. 206 3.2. Types of IP Addresses 208 Four types of IP addresses are defined with respect to mobility 209 management. 211 - Fixed IP Address 213 A Fixed IP address is an address with a guarantee to be valid for a 214 very long time, regardless of whether it is being used in any packet 215 to/from the mobile host, or whether or not the mobile host is 216 connected to the network, or whether it moves from one point-of- 217 attachment to another (with a different IP prefix) while it is 218 connected. 220 Fixed IP addresses are required by applications that need both 221 session continuity and IP address reachability. 223 - Session-lasting IP Address 225 A session-lasting IP address is an address with a guarantee to be 226 valid throughout the life-time of the socket(s) for which it was 227 requested. It is guaranteed to be valid even after the mobile host 228 had moved from one point-of-attachment to another (with a different 229 IP prefix). 231 Session-lasting IP addresses are required by applications that need 232 session continuity but do not need IP address reachability. 234 - Non-persistent IP Address 236 This type of IP address has no guarantee to exist after a mobile host 237 moves from one point-of-attachment to another, and therefore, no 238 session continuity nor IP address reachability are provided. The IP 239 address is created from an IP prefix that is obtained from the 240 serving IP gateway and is not maintained across gateway changes. In 241 other words, the IP prefix may be released and replaced by a new one 242 when the IP gateway changes due to the movement of the mobile host 243 forcing the creation of a new source IP address with the updated 244 allocated IP prefix. 246 - Graceful Replacement IP Address 248 In some cases, the network cannot guarantee the validity of the 249 provided IP prefix throughout the duration of the opened socket, but 250 can provide a limited graceful period of time in which both the 251 original IP prefix and a new one are valid. This enables the 252 application some flexibility in the transition from the existing 253 source IP address to the new one. 255 This gracefulness is still better than the non-persistence type of 256 address for applications that can handle a change in their source IP 257 address but require that extra flexibility. 259 Applications running as servers at a published IP address require a 260 Fixed IP Address. Long-standing applications (e.g., an SSH session) 261 may also require this type of address. Enterprise applications that 262 connect to an enterprise network via virtual LAN require a Fixed IP 263 Address. 265 Applications with short-lived transient sessions can use Session- 266 lasting IP Addresses. For example: Web browsers. 268 Applications with very short sessions, such as DNS clients and 269 instant messengers, can utilize Non-persistent IP Addresses. Even 270 though they could very well use Fixed or Session-lasting IP 271 Addresses, the transmission latency would be minimized when a Non- 272 persistent IP Addresses are used. 274 Applications that can tolerate a short interruption in connectivity 275 can use the Graceful-replacement IP addresses. For example, a 276 streaming client that has buffering capabilities. 278 3.3. Granularity of Selection 280 IP address type selection is made on a per-socket granularity. 281 Different parts of the same application may have different needs. 282 For example, the control-plane of an application may require a Fixed 283 IP Address in order to stay reachable, whereas the data-plane of the 284 same application may be satisfied with a Session-lasting IP Address. 286 3.4. On Demand Nature 288 At any point in time, a mobile host may have a combination of IP 289 addresses configured. Zero or more Fixed, zero or more Session- 290 lasting, zero or more Non-persistent and zero or more Graceful- 291 Replacement IP addresses may be configured by the IP stack of the 292 host. The combination may be as a result of the host policy, 293 application demand, or a mix of the two. 295 When an application requires a specific type of IP address and such 296 an address is not already configured on the host, the IP stack SHALL 297 attempt to configure one. For example, a host may not always have a 298 Session-lasting IP address available. When an application requests 299 one, the IP stack SHALL make an attempt to configure one by issuing a 300 request to the network (see Section 3.5 below for more details). If 301 the operation fails, the IP stack SHALL fail the associated socket 302 request and return an error. If successful, a Session-lasting IP 303 Address gets configured on the mobile host. If another socket 304 requests a Session-lasting IP address at a later time, the same IP 305 address may be served to that socket as well. When the last socket 306 using the same configured IP address is closed, the IP address may be 307 released or kept for future applications that may be launched and 308 require a Session-lasting IP address. 310 In some cases it might be preferable for the mobile host to request a 311 new Session-lasting IP address for a new opening of an IP socket 312 (even though one was already assigned to the mobile host by the 313 network and might be in use in a different, already active IP 314 sockets). It is outside the scope of this specification to define 315 criteria for choosing to use available addresses or choosing to 316 request new ones. It supports both alternatives (and any 317 combination). 319 It is outside the scope of this specification to define how the host 320 requests a specific type of prefix and how the network indicates the 321 type of prefix in its advertisement or in its reply to a request. 323 The following are matters of policy, which may be dictated by the 324 host itself, the network operator, or the system architecture 325 standard: 327 - The initial set of IP addresses configured on the host at boot 328 time. 330 - Permission to grant various types of IP addresses to a requesting 331 application. 333 - Determination of a default address type when an application does 334 not make any explicit indication, whether it already supports the 335 required API or it is just a legacy application. 337 3.5. Conveying the Desired Address Type 339 [RFC5014] introduced the ability of applications to influence the 340 source address selection with the IPV6_ADDR_PREFERENCE option at the 341 IPPROTO_IPV6 level. This option is used with setsockopt() and 342 getsockopt() calls to set/get address selection preferences. 344 Extending this further by adding more flags does not work when a 345 request for an address of a certain type results in requiring the IP 346 stack to wait for the network to provide the desired source IP prefix 347 and hence causing the setsockopt() call to block until the prefix is 348 allocated (or an error indication from the network is received). 350 Alternatively a new socket API is defined - setsc() which allows 351 applications to express their desired type of session continuity 352 service. The new setsc() API will return an IPv6 address that is 353 associated with the desired session continuity service and with 354 status information indicating whether or not the desired service was 355 provided. 357 An application that wishes to secure a desired service will call 358 setsc() with the service type definition and a place to contain the 359 provided IP address, and call bind() to associate that IP address 360 with the socket (See pseudo-code example in Section 4 below). 362 When the IP stack is required to use a source IP address of a 363 specified type, it can use an existing address, or request a new IP 364 prefix (of the same type) from the network and create a new one. If 365 the host does not already have an IPv6 prefix of that specific type, 366 it MUST request one from the network. 368 Using an existing address from an existing prefix is faster but might 369 yield a less optimal route (if a hand-off event occurred after its 370 configuration). On the other hand, acquiring a new IP prefix from 371 the network may be slower due to signaling exchange with the network. 373 Applications can control the stack's operation by setting a new flag 374 - ON_NET flag - which directs the IP stack whether to use a 375 preconfigured source IP address (if exists) or to request a new IPv6 376 prefix from the current serving network and configure a new IP 377 address. 379 This new flag is added to the set of flags in the 380 IPV6_ADDR_PREFERENCES option at the IPPROTO_IPV6 level. It is used 381 in setsockopt() to set the desired behavior. 383 4. Usage example 385 4.1. Pseudo-code example 387 The following example shows pseudo-code for creating a Stream socket 388 (TCP) with a Session-Lasting source IP address: 390 #include 391 #include 393 // Socket information 394 int s ; // socket id 396 // Source information (for setsc() and bind()) 397 sockaddr_in6 sourceInfo // my address and port for bind() 398 in6_addr sourceAddress // will contain the provisioned 399 // source IP address 400 uint8_t sc_type = IPV6_REQUIRE_SESSION_LASTING_IP ; 401 // For requesting a Session-Lasting 402 // source IP address 404 // Destination information (for connect()) 405 sockaddr_in6 serverInfo ; // server info for connect() 407 // Create an IPv6 TCP socket 408 s = socket(AF_INET6, SOCK_STREAM, 0) ; 409 if (s!=0) { 410 // Handle socket creation error 411 // ... 412 } // if socket creation failed 413 else { 414 // Socket creation is successful 415 // The application cannot connect yet, since it wants to use 416 // a Session-Lasting source IP address It needs to request 417 // the Session-Lasting source IP before connecting 418 if (setsc(s, &sourceAddress, &sc_type)) == 0){ 419 // setting session continuity to Session Lasting is 420 // Successful. sourceAddress now contains the Session- 421 // LAsting source IP address 422 // Bind to that source IP address 423 sourceInfo.sin6_family = AF_INET6 ; 424 sourceInfo.sin6_port = 0 // let the stack choose the port 425 sourceInfo.sin6_address = sourceAddress ; 426 // Use the source address that was 427 // generated by the setsc() call 428 if (bind(s, &sourceInfo, sizeof(sourceInfo))==0){ 429 // Set the desired server's information for connect() 430 serverInfo.sin6_family = AF_INET6 ; 431 serverInfo.sin6_port = SERVER_PORT_NUM ; 432 serverAddress.sin6_addr = SERVER_IPV6_ADDRESS ; 434 // Connect to the server 435 if (connect(s, &serverInfo, sizeof(serverInfo))==0) { 436 // connect successful (3-way handshake has been 437 // completed with Session-Lasting source address. 438 // Continue application functionality 439 // ... 440 } // if connect() is successful 441 else { 442 // connect failed 443 // ... 444 // Application code that handles connect failure and 445 // closes the socket 446 // ... 447 } // if connect() failed 448 } // if bind() successful 449 else { 450 // bind() failed 451 // ... 452 // Application code that handles bind failure and 453 // closes the socket 454 // ... 455 } // if bind() failed 456 } // if setsc() was successful and of a Session-Lasting 457 // source IP address was provided 458 else { 459 // application code that does not use Session-lasting IP 460 // address. The application may either connect without 461 // the desired Session-lasting service, or close the 462 // socket... 463 } // if setsc() failed 464 } // if socket was created successfully 466 // The rest of the application's code 467 // ... 469 4.2. Message Flow example 471 The following message flow illustrates a possible interaction for 472 achieving On-Demand functionality. It is an example of one scenario 473 and should not be regarded as the only scenario or the preferred one. 475 This flow describes the interaction between the following entities: 477 - Applications requiring different types of On-Demand service. 479 - The mobile host's IP stack. 481 - The network infrastructure providing the services. 483 In this example, the network infrastructure provides 2 IPv6 prefixes 484 upon attachment of the mobile host to the network: A Session-lasting 485 IPv6 prefix and a Non-persistent IPv6 prefix. Whenever the mobile 486 host moves to a different point-of-attachment, the network 487 infrastructure provides a new Non-persistent IPv6 address. 489 In this example, the network infrastructure does not support Fixed IP 490 addresses nor Graceful-replacement IP addresses. 492 Whenever an application opens an IP socket and requests a specific 493 IPv6 address type, the IP stack will provide one from its available 494 IPv6 prefixes or return an error message if the request cannot be 495 fulfilled. 497 Message Flow: 499 - The mobile device attaches to the network. 501 - The Network provides two IPv6 prefixes: PREFsl1 - a Session-lasting 502 IPv6 prefix and PREFnp1 - a Non-persistent IPv6 prefix. 504 - An application on the mobile host is launched. It opens an IP 505 socket and requests a Non-persistent IPv6 address. 507 - The IP stack provides IPnp1 which is generated from PREFnp1. 509 - Another application is launched, requesting a Non-persistent IPv6 510 address. 512 - The IP stack provides IPnp1 again. 514 - A third application is launched. This time, it requires a Session- 515 lasting IPv6 address. 517 - The IP stack provides IPsl1 which is generated from PREFsl1. 519 - The mobile hosts moves to a new point-of-attachment. 521 - The network provides a new Non-persistent IPv6 prefix - PREFnp2. 522 PREFnp1 is no longer valid. 524 - The applications that were given IPnp1 re-establish the socket and 525 receive a new IPv6 address - IPnp2 which is generated from PREFnp2 527 - The application that is using IPsl1 can still use it since the 528 network guaranteed that PREFsl1 will be valid even after moving to a 529 new point-of-attachment. 531 - A new application is launched, this time requiring a Graceful- 532 replacement IPv6 address. 534 - The IP stack returns setsc() with an error since the network does 535 not support this service. 537 - The application re-attempts to open a socket, this time requesting 538 a Session-lasting IPv6 address. 540 - The IP stack provides IPsl1. 542 5. Backwards Compatibility Considerations 544 Backwards compatibility support is REQUIRED by the following 3 types 545 of entities: 547 - The Applications on the mobile host 549 - The IP stack in the mobile host 551 - The network infrastructure 553 5.1. Applications 555 Legacy applications that do not support the On-Demand functionality 556 will use the legacy API and will not be able to take advantage of the 557 On-Demand Mobility feature. 559 Applications using the new On-Demand functionality MUST be aware that 560 they may be executed in legacy environments that do not support it. 561 Such environments may include a legacy IP stack on the mobile host, 562 legacy network infrastructure, or both. In either case, the API will 563 return an error code and the invoking applications may just give up 564 and use legacy calls. 566 5.2. IP Stack in the Mobile Host 568 New IP stacks MUST continue to support all legacy operations. If an 569 application does not use On-Demand functionality, the IP stack MUST 570 respond in a legacy manner. 572 If the network infrastructure supports On-Demand functionality, the 573 IP stack SHOULD follow the application request: If the application 574 requests a specific address type, the stack SHOULD forward this 575 request to the network. If the application does not request an 576 address type, the IP stack MUST NOT request an address type and leave 577 it to the network's default behavior to choose the type of the 578 allocated IP prefix. If an IP prefix was already allocated to the 579 host, the IP stack uses it and may not request a new one from the 580 network. 582 5.3. Network Infrastructure 584 The network infrastructure may or may not support the On-Demand 585 functionality. How the IP stack on the host and the network 586 infrastructure behave in case of a compatibility issue is outside the 587 scope of this API specification. 589 5.4. Merging this work with RFC5014 591 [RFC5014] defines new flags that may be used with setsockopt() to 592 influence source IP address selection for a socket. The list of 593 flags include: source home address, care-of address, temporary 594 address, public address CGA (Cryptographically Created Address) and 595 non-CGA. When applications require session continuity service and 596 use setsc() and bind(), they SHOULD NOT set the flags specified in 597 [RFC5014]. 599 However, if an application erroneously performs a combination of (1) 600 Use setsockopt() to set a specific option (using one of the flags 601 specified in [RFC5014]) and (2) Selects a source IP address type 602 using setsc() and bind(), the IP stack will fulfill the request 603 specified by (2) and ignore the flags set by (1). 605 If bind() was not invoked after setsc() by the application, the IP 606 address generated by setsc() will not be used and traffic generated 607 by the socket will use a source IP address that complies with the 608 options selected by setsockopt(). 610 6. Summary of New Definitions 612 6.1. New APIs 614 setsc() enables applications to request a specific type of source IP 615 address in terms of session continuity. Its definition is: 617 int setsc(int sockfd, in6_addr *sourceAddress, sc_type addressType); 619 Where: 620 - sockfd - is the socket descriptor of the socket with which 621 a specific address type is associated 622 - sourceAddress - is a pointer to an area allocated for setsc() to 623 place the generated source IP address of the 624 desired session continuity type 625 - addressType - Is the desired type of session continuity service. 626 It is a 3-bit field containing one of the 627 following values: 628 0 - Reserved 629 1 - FIXED_IPV6_ADDRESS 630 2 - SESSION_LASTING_IPV6_ADDRESS 631 3 - NON_PERSISTENT_IPV6_ADDRESS 632 4 - GRACEFUL_REPLACEMENT_IPV6_ADDRESS 633 5-7 - Reserved 635 setsc() returns the status of the operation: 636 - 0 - Address was successfully generated 637 - EAI_REQUIREDIPNOTSUPPORTED - the required service type is not 638 supported 639 - EAI_REQUIREDIPFAILED - the network could not fulfill the desired 640 request 642 setsc() MAY block the invoking thread if it triggers the TCP/IP stack 643 to request a new IP prefix from the network to construct the desired 644 source IP address. If an IP prefix with the desired session 645 continuity features already exists (was previously allocated to the 646 mobile host) and the stack is not required to request a new one as a 647 result of setting the IPV6_REQUIRE_SRC_ON_NET flag (defined below), 648 setsc() MAY return immediately with the constructed IP address and 649 will not block the thread. 651 6.2. New Flags 653 The following flag is added to the list of flags in the 654 IPV6_ADDR_PREFERENCE option at the IPPROTO6 level: 656 IPV6_REQUIRE_SRC_ON_NET - set IP stack address allocation behavior 657 If set, the IP stack will request a new IPv6 prefix of the desired 658 type from the current serving network and configure a new source IP 659 address. If reset, the IP stack will use a preconfigured one if it 660 exists. If there is no preconfigured IP address of the desired type, 661 a new prefix will be requested and used for creating the IP address. 663 7. Security Considerations 665 The setting of certain IP address type on a given socket may be 666 restricted to privileged applications. For example, a Fixed IP 667 Address may be provided as a premium service and only certain 668 applications may be allowed to use them. Setting and enforcement of 669 such privileges are outside the scope of this document. 671 8. IANA Considerations 673 This document has no IANA considerations. 675 9. Contributors 677 This document was merged with [I-D.sijeon-dmm-use-cases-api-source]. 678 We would like to acknowledge the contribution of the following people 679 to that document as well: 681 Sergio Figueiredo 682 Altran Research, France 683 Email: sergio.figueiredo@altran.com 685 Younghan Kim 686 Soongsil University, Korea 687 Email: younghak@ssu.ac.kr 689 John Kaippallimalil 690 Huawei, USA 691 Email: john.kaippallimalil@huawei.com 693 10. Acknowledgements 695 We would like to thank Wu-chi Feng, Alexandru Petrescu, Jouni 696 Korhonen, Sri Gundavelli, Dave Dolson and Lorenzo Colitti for their 697 valuable comments and suggestions on this work. 699 11. References 700 11.1. Normative References 702 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 703 Requirement Levels", BCP 14, RFC 2119, 704 DOI 10.17487/RFC2119, March 1997, 705 . 707 [RFC5014] Nordmark, E., Chakrabarti, S., and J. Laganier, "IPv6 708 Socket API for Source Address Selection", RFC 5014, 709 DOI 10.17487/RFC5014, September 2007, 710 . 712 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 713 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 714 May 2017, . 716 11.2. Informative References 718 [I-D.sijeon-dmm-use-cases-api-source] 719 Jeon, S., Figueiredo, S., Kim, Y., and J. Kaippallimalil, 720 "Use Cases and API Extension for Source IP Address 721 Selection", draft-sijeon-dmm-use-cases-api-source-07 (work 722 in progress), September 2017. 724 [RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, 725 A., Peterson, J., Sparks, R., Handley, M., and E. 726 Schooler, "SIP: Session Initiation Protocol", RFC 3261, 727 DOI 10.17487/RFC3261, June 2002, 728 . 730 [RFC5213] Gundavelli, S., Ed., Leung, K., Devarapalli, V., 731 Chowdhury, K., and B. Patil, "Proxy Mobile IPv6", 732 RFC 5213, DOI 10.17487/RFC5213, August 2008, 733 . 735 [RFC5563] Leung, K., Dommety, G., Yegani, P., and K. Chowdhury, 736 "WiMAX Forum / 3GPP2 Proxy Mobile IPv4", RFC 5563, 737 DOI 10.17487/RFC5563, February 2010, 738 . 740 [RFC5944] Perkins, C., Ed., "IP Mobility Support for IPv4, Revised", 741 RFC 5944, DOI 10.17487/RFC5944, November 2010, 742 . 744 [RFC6275] Perkins, C., Ed., Johnson, D., and J. Arkko, "Mobility 745 Support in IPv6", RFC 6275, DOI 10.17487/RFC6275, July 746 2011, . 748 [RFC6824] Ford, A., Raiciu, C., Handley, M., and O. Bonaventure, 749 "TCP Extensions for Multipath Operation with Multiple 750 Addresses", RFC 6824, DOI 10.17487/RFC6824, January 2013, 751 . 753 [RFC7333] Chan, H., Ed., Liu, D., Seite, P., Yokota, H., and J. 754 Korhonen, "Requirements for Distributed Mobility 755 Management", RFC 7333, DOI 10.17487/RFC7333, August 2014, 756 . 758 Authors' Addresses 760 Alper Yegin 761 Actility 762 Istanbul 763 Turkey 765 Email: alper.yegin@actility.com 767 Danny Moses 768 Intel Corporation 769 Petah Tikva 770 Israel 772 Email: danny.moses@intel.com 774 Kisuk Kweon 775 Samsung 776 Suwon 777 South Korea 779 Email: kisuk.kweon@samsung.com 781 Jinsung Lee 782 Samsung 783 Suwon 784 South Korea 786 Email: js81.lee@samsung.com 787 Jungshin Park 788 Samsung 789 Suwon 790 South Korea 792 Email: shin02.park@samsung.com 794 Seil Jeon 795 Sungkyunkwan University 796 Suwon 797 South Korea 799 Email: seiljeon@skku.edu