Internet Engineering Task Force                                  G. Chen
Internet-Draft                                              China Mobile
Intended status: Informational                               C. Williams
Expires: May 17, 2017                                         Consultant
                                                                 D. Wing
                                                          A. Yourtchenko
                                                     Cisco Systems, Inc.
                                                       November 13, 2016

            Happy Eyeballs Extension for Multiple Interfaces


   This memo proposes extensions to the Happy Eyeball's algorithm
   requirements defined in RFC6555 for use with the multiple
   provisioning domain architecture.  The Happy Eyeballs in MIF would
   make the selection process smoother by using connectivity tests over
   pre-filtered interfaces according to defined policy.  This would
   choose the best interface with an automatic fallback mechanism.

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

   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 May 17, 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
   ( in effect on the date of
   publication of this document.  Please review these documents

Chen, et al.              Expires May 17, 2017                  [Page 1]

Internet-Draft             happy-eyeballs-mif              November 2016

   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  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Use Cases . . . . . . . . . . . . . . . . . . . . . . . . . .   3
     3.1.  WiFi is broken  . . . . . . . . . . . . . . . . . . . . .   3
     3.2.  Policy Conflict . . . . . . . . . . . . . . . . . . . . .   4
   4.  Happiness Parameters  . . . . . . . . . . . . . . . . . . . .   4
     4.1.  Hard Set  . . . . . . . . . . . . . . . . . . . . . . . .   5
       4.1.1.  Operator Policy . . . . . . . . . . . . . . . . . . .   5
       4.1.2.  User Preference . . . . . . . . . . . . . . . . . . .   5
     4.2.  Soft Set  . . . . . . . . . . . . . . . . . . . . . . . .   6
       4.2.1.  Provisioning Domain Identity  . . . . . . . . . . . .   6
       4.2.2.  DNS Selection . . . . . . . . . . . . . . . . . . . .   6
       4.2.3.  Next Hop  . . . . . . . . . . . . . . . . . . . . . .   6
       4.2.4.  Source Address Selection  . . . . . . . . . . . . . .   6
       4.2.5.  Common Practice . . . . . . . . . . . . . . . . . . .   6
   5.  HE-MIF Process Requirements . . . . . . . . . . . . . . . . .   7
     5.1.  First Step, Filter  . . . . . . . . . . . . . . . . . . .   7
     5.2.  Second Step, Sort . . . . . . . . . . . . . . . . . . . .   8
       5.2.1.  Interface Validation  . . . . . . . . . . . . . . . .   8
       5.2.2.  Name Resolution . . . . . . . . . . . . . . . . . . .   8
       5.2.3.  Connection Establishment  . . . . . . . . . . . . . .   8
   6.  Implementation Framework  . . . . . . . . . . . . . . . . . .   9
   7.  Additional Considerations . . . . . . . . . . . . . . . . . .   9
     7.1.  Usage Scope . . . . . . . . . . . . . . . . . . . . . . .   9
     7.2.  Fallback Timeout  . . . . . . . . . . . . . . . . . . . .   9
     7.3.  DNS Selections  . . . . . . . . . . . . . . . . . . . . .  10
     7.4.  Flow Continuity . . . . . . . . . . . . . . . . . . . . .  11
     7.5.  Interworking with Happy Eyeball . . . . . . . . . . . . .  11
     7.6.  Multipath Applicability . . . . . . . . . . . . . . . . .  11
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  11
   9.  Security Considerations . . . . . . . . . . . . . . . . . . .  12
   10. Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  12
   11. References  . . . . . . . . . . . . . . . . . . . . . . . . .  12
     11.1.  Normative References . . . . . . . . . . . . . . . . . .  12
     11.2.  Informative References . . . . . . . . . . . . . . . . .  13
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  14

Chen, et al.              Expires May 17, 2017                  [Page 2]

Internet-Draft             happy-eyeballs-mif              November 2016

1.  Introduction

   The MIF problem statement [RFC6418] describes problems specific for
   nodes attached to multiple provisioning domains.  Specifically, there
   is a issue description that a node has selected an interface and
   obtained a valid IP address from the network, but Internet
   connectivity is not available.  This memo intends to address the
   issue and elaborate more in Section 3.1.

   [RFC7556] describes the multiple provisioning domain architecture.
   It refers to using connectivity tests to validate a Provisioning
   Domain (PvD).  Given a number of implicit/explicit PvDs, plus
   preferences/policy, what is the process to follow to select the best
   PvD to use for any given connection.  In the event that two or more
   are deemed to be best, how are the Happy Eyeballs (HE) techniques
   applied to find the best and deal with resilience.  This memo also
   proposes process requirements using Happy Eyeballs (HE) extensions.

   There are a variety of algorithms that can be envisioned.  This
   document describes additional parameters and processes that need to
   be considered in addition to the HE algorithm requirements defined in
   [RFC6555] necessary to support multiple interfaces, so that a node
   with multiple interfaces can select the best path for a particular
   connection-oriented flow (e.g., TCP, SCTP).

2.  Terminology

   This document makes use of following terms:

   o  Happy Eyeballs (HE): specifies requirements for an algorithm that
      reduces the user-visible connection delay for dual-stack hosts
      with a single interface per-protocol.

   o  Happy Eyeballs - Multi-Interface (HE-MIF): Extends the Happy
      Eyeballs concept to the multiple provisioning domain architecture.
      It describes additional requirements for algorithms that offer
      connectivity tests on PVD-aware or non-PVD-aware nodes [RFC7556]
      to select the best interface for a specific connection request.

3.  Use Cases

   The section describes scenarios the HE-MIF targeted to use.

3.1.  WiFi is broken

   Assuming a MIF node has both a 3GPP mobile network interface and a
   WiFi interface, a common practice would be to always prefer the WiFi
   connection when the node enters an area with WiFi available.  In this

Chen, et al.              Expires May 17, 2017                  [Page 3]

Internet-Draft             happy-eyeballs-mif              November 2016

   situation, a node might assume that because a valid IP address has
   been allocated, the WiFi link provides connectivity to destinations
   through the Internet.  However, this might not be the case for
   several reasons:

   o  WiFi access-point authentication requirements

   o  WiFi has no global Internet connectivity

   o  Instability at layer 2

   In order to resolve this problem, the user would need to disable the
   device's interface preferences, e.g. by disabling the WiFi interface.
   HE-MIF offers users the possibility of configuring their preferences
   for the choice of the most suitable network interface to use, such as
   via setting on their mobile phone.

   In this case, users may prefer to wait an appropriate time period for
   connections to be established over a WiFi path.  If no connection can
   be made it will fall back to attempting the connection over a 3GPP
   mobile network path.

3.2.  Policy Conflict

   A node has network access via both WiFi and 3GPP networks.  In a
   mobile network, IPv6-only may be preferable since IPv6 has the
   potential to be simpler than dual-stack.  The WiFi access offers IPv4
   only.  In this scenario, the combination of source address selection
   [RFC6724] and preferring the WiFi interface may cause a problem.  The
   transition to IPv6 may mean that IPv6 is the preferred protocol, so
   the 3GPP interface should be chosen even though it could be
   considered a suboptimal selection e.g. the WiFi interface likely is
   less expensive.

4.  Happiness Parameters

   This section provides input parameter proposal that HE-MIF should
   catch.  Two sets of "Happiness" parameters have been defined.  It
   serves applications and initiates HE-MIF connection tests
   subsequently.  By following the process described below, MIF nodes
   can select an appropriate interface that best meets the configuration
   parameters defined by the user.  The two sets of "Happiness"
   parameters are called Hard Set and Soft Set respectively.

Chen, et al.              Expires May 17, 2017                  [Page 4]

Internet-Draft             happy-eyeballs-mif              November 2016

4.1.  Hard Set

   Hard set contains parameters which should be complied with.  It helps
   to select candidate interfaces through which a particular flow should
   be directed.  These should be seen as constraints on the choice, such
   as provider policies, support for IPv4 or IPv6, and other parameters
   which would prevent a particular interface and transport from being
   used by a particular flow.  Parameters in the hard set should be easy
   to use and understand.  When several parameters in the hard set are
   in conflict, the user's preference should be prioritized.

4.1.1.  Operator Policy

   Operators may deliver the customized policies for a particular
   network environment because of geo-location or service regulation
   considerations.  One example relevant for 3GPP networks is an
   operator delivering policies from an Access Network Discovery and
   Selection function (ANDSF) [TS23.402].

   The ANDSF provides a node with policies and network selection
   information to influence the selection between different access
   technologies, such as 3GPP mobile networks, WiFi access.  The ANDSF
   can provide the node with three types of information[TS24.302].

   o  Access network discovery and selection information: it includes a
      list of access networks available in the vicinity of the node.
      The information may include the access technology types (e.g.
      WiFi), network identifiers (e.g.  SSID in the case of WiFi) as
      well as validity conditions (e.g. where and when).

   o  Inter-System Mobility Policies (ISMPs): they are a set of
      operator-defined rules and preferences that affect the inter-
      system mobility decisions, e.g. decisions about whether to use
      3GPP mobile network or a WiFi network.

   o  Inter-System Routing Policies (ISRPs): the node uses ISRPs when it
      can route IP traffic simultaneously over multiple radio access
      networks.  It could provide routing policies in an IP flow

4.1.2.  User Preference

   User's preference: users may express preferences which likely not
   have a formally technical language , like "No 3/4G while roaming",
   "Only download applications larger than 20Mb over WiFi", etc.  Those
   information are normally input from User Interface (UI).

Chen, et al.              Expires May 17, 2017                  [Page 5]

Internet-Draft             happy-eyeballs-mif              November 2016

4.2.  Soft Set

   Soft set contains factors which impact the selection of the path
   across which a particular flow should be transmitted among the
   available interfaces and transports which meet the hard set
   requirements described above.

4.2.1.  Provisioning Domain Identity

   A PVD-aware node uses PvD Identity(PvD-ID) to select a PvD with a
   matching ID for special-purpose connection requests.  The PvD-ID may
   be generated by the node implicitly or received from the network
   explicitly. for explicit PvDs, the node could take the parameter from
   PvD ID Option [I-D.ietf-mif-mpvd-id] via the configuration protocols
   ([I-D.ietf-mif-mpvd-dhcp-support] or
   [I-D.ietf-mif-mpvd-ndp-support]).  A PVD-aware node may decide to use
   one preferred PVD or allow the use of multiple PVDs simultaneously
   for applications.  The node behavior should be consistent with MPVD
   architecture [RFC7556].

4.2.2.  DNS Selection

   At the name service lookup step, the node has to choose a recursive
   DNS server to use.  A HE-MIF node should take the parameter of RDNSS
   Selection DHCP Option [RFC6731] to select an interface for a
   particular namespace.

4.2.3.  Next Hop

   [RFC4191] allows the configuration of specific routes to a
   destination.  A HE-MIF node should take the parameters of router
   preference and route information to identify the next hop.

4.2.4.  Source Address Selection

   For each destination, once the best next hop is found, the node
   should consider IP prefix and precedence parameter in policy table to
   select the best source address according to the rule defined in

4.2.5.  Common Practice

   There is relevant common practice related to interface selection,
   e.g.  Prefer WiFi over a 3GPP interface, if available.  Such
   conventions should also be considered.

Chen, et al.              Expires May 17, 2017                  [Page 6]

Internet-Draft             happy-eyeballs-mif              November 2016

5.  HE-MIF Process Requirements

   An HE-MIF node may use the two sets of parameters as two steps in the
   interface selection process.  The first step is to use the Hard Set
   to synthesize policies from different actors (e.g., users or network
   operators).  These hard set parameters will provide a filter which
   will exclude not qualifying interfaces from any further

   The second step is to influence how a node makes a connection when
   multiple interfaces still remain in the candidate list after first
   step.  This is essentially sorting behavior.  In the multiple
   provisioning domain architecture, a PVD aware node makes connectivity
   tests as described in Section 5.3 of [RFC7556].  A PVD agnostic node
   take other parameters apart from PVD-ID in the Soft Set to proceed
   the sort process.

   The two steps are described in more details in the following sub-
   sections.  It should be noted that HE-MIF does not prescribe such
   two-step model.  It will be very specific to particular cases and
   implementations.  The two step model mainly describes requirements
   for how to use the hard/soft set.

5.1.  First Step, Filter

   One goal of the filter is to reconcile multiple selection policies
   from users or operators.  Afterwards, merged demands would be mapped
   to a set of candidate interfaces, which are judged as qualified.

   Decision on the reconciliation of different policies will depend very
   much on the deployment scenario.  An implementation may not be able
   to determine priority for each policies without explicit
   configuration provided by users or administrator.  For example, an
   implementation may by default always prefer the WiFi because of cost
   saving consideration.  Whereas, other users may turn off a device's
   WiFi interface to guarantee use of a 3GPP network interface to assure
   higher reliability or security.

   The decision on mergence of policies may be made by implementations,
   or by node administrators.  However, it's worth to note that a demand
   from users should be normally considered higher priority than from
   other actors.

   The merged policies serve as a filter which is iterated across the
   list of available interfaces.  Qualified interfaces are selected and
   the proceed to the second step.

Chen, et al.              Expires May 17, 2017                  [Page 7]

Internet-Draft             happy-eyeballs-mif              November 2016

5.2.  Second Step, Sort

5.2.1.  Interface Validation

   The Sort process aims to select the best interface and provide
   fallback capacities.  As stated in [RFC7556], a PVD-aware node shall
   perform connectivity tests and, only after validation of the PVD,
   consider using it to serve application connections requests.  In
   current implementations, some nodes already implement this, e.g., by
   trying to reach a dedicated web server (see Section 3.1.2 [RFC6419]
   ).  If anything is abnormal, it assumes there is a proxy on the path.
   This status detection is recommended to be used in HE-MIF to detect
   DNS interception or an HTTP proxy that forces a login or a click-
   through.  Unexamined PVDs or interfaces should be accounted as
   "unconnected".  It should not join the sort process.

5.2.2.  Name Resolution

   Name resolution is executed on the validated interfaces.  Before the
   requests are initiated, it should check if there is a matching PVD ID
   for the destination name.  A PVD agnostic node may request DNS server
   selection DHCP option [RFC6731] for interface selection guidance.
   Those information may weight a particular interface to be preferred
   to others sending resolving requests.  If the node can't find useful
   information in the Soft Set, DNS queries would be sent out on
   multiple interfaces in parallel to maximize chances for connectivity.
   Some additional discussions of DNS selection consideration of HE-MIF
   are described in Section 7.3.

5.2.3.  Connection Establishment

   Once a destination address was resolved, a connection is to be setup.
   For the given destination address, a PVD-aware node selects a next-
   hop and source address associated with that PVD in the name
   resolution process.  A PVD agnostic node may receive certain next hop
   in a RA message [RFC4191], the node selects best source address
   according to the rules [RFC6724].

   The interface identified by the source address should be treated to
   initiate the connection prior to others.  This could avoid thrashing
   the network, by not making simultaneous connection attempts on
   multiple interfaces.  After making a connection attempt on the
   preferred pairs and failing to establish a connection within a
   certain time period (see Section 7.2), a HE-MIF implementation will
   decide to initiate connection attempt using rest of interfaces in
   parallel.  This fallback consideration will make subsequent
   connection attempts successful on non-preferable interfaces.

Chen, et al.              Expires May 17, 2017                  [Page 8]

Internet-Draft             happy-eyeballs-mif              November 2016

   The node would cache information regarding the outcome of each
   connection attempt.  Cache entries would be flushed periodically.  A
   system-defined timeout may take place to age the state.  Maximum on
   the order of 10 minutes defined in [RFC6555] is recommended to keep
   the interface state changes synchronizing with IP family states.

   If there is no specific Soft Set provided, all selected interfaces
   should be treated equally. for a node implementing multipath
   transports (for example, Multipath TCP (MPTCP) [RFC6182]), the
   interfaces could be treated as valid to perform subsequent multipath
   process, such as starting subflow.  A node only supporting single
   physical transport would initiate on several interface
   simultaneously.  The goal here is to provide the most fast connection
   for users, by quickly attempting to connect using each candidate
   interface.  Afterwards, the node would do the same caching and
   flushing process as described above.

6.  Implementation Framework

   The simplest way to implement the processes described in this
   document is within the application itself.  This would not require
   any specific support from the operating system beyond the commonly
   available APIs that provide transport service.  It could also be
   implemented using a high-level API approach, linking to the MIF-API

7.  Additional Considerations

7.1.  Usage Scope

   Connection-oriented transports (e.g., TCP, SCTP) are directly applied
   as scoped in [RFC6555].  For connectionless transport protocols
   (e.g., UDP), a similar mechanism can be used if the application has
   request/response semantics.  Further investigations are out of the
   document scope.

7.2.  Fallback Timeout

   When the preferred interface was failed, HE-MIF would trigger a
   fallback process to start connection initiation on several candidate
   interfaces.  A period of time should be set to invalidate the
   interface and fallback to others.  Aggressive timeouts may achieve
   quick interface handover, but at the cost of traffic that may be
   chargeable on certain networks, e.g. the handover from WiFi to 3GPP
   networks brings a charge to customers.  Considering the reasons, it
   is recommended to prioritize the input from users (e.g., real
   customers or applications) through user interface.  For default-
   setting on a system, a hard error [RFC1122] in replied ICMP could

Chen, et al.              Expires May 17, 2017                  [Page 9]

Internet-Draft             happy-eyeballs-mif              November 2016

   serve as a trigger for the fallback process.  When the ICMP soft
   error is present or non-response was received, it's recommended that
   the timeout should be large enough to allow connection
   retransmission.  [RFC1122] states that such timer must be at least 3
   minutes to provide TCP retransmission.  However, several minutes
   delay may not inappropriate for user experiences.  A widespread
   practice [RFC5461] sets 75 seconds to optimize connection process.

   More optimal timer may be expected.  The particular setting will be
   very specific to implementations and cases.  The memo didn't try to
   provide a concrete value because of following concerns.

   o  RTT (Round-Trip Time) on different interfaces may vary quite a
      lot.  A particular value of timeout may not accurately help to
      make a decision that this interface doesn't work at all.  On the
      contrary, it may cause a misjudgment on a interface, which is not
      very fast.  In order to compensate the issues, the timeout setting
      based on past experiences of a particular interface may help to
      make a fair decision.  Whereas, it's going beyond the capability
      of Happy Eyeballs [RFC6555].  Therefore, it leaves a particular

   o  In some cases, fast interface may not be treated as "best".  For
      example, a interface could be evaluated in the principle of
      bandwidth-delay, termed "Bandwidth-Delay-Product ".  Happy
      Eyeballs measures only connection speed.  That is, how quickly a
      TCP connection is established . It does not measure bandwidth.  If
      the fallback has to take various factors into account and make
      balanced decision, it's better to resort to a specific context and

7.3.  DNS Selections

   During the Sort process, HE-MIF prioritizes PVD-ID match or [RFC6731]
   inputs to select a proper server.  It could help to address following
   two cases.

   o  A DNS answer may be only valid for a specific provisioning domain,
      but the DNS resolver may not be aware of that because the DNS
      reply is not kept with the provisioning from which the answer
      comes.  The situation may become worse if asking internal name
      with public address response or asking public name with private
      address answers.

   o  Some FQDNs can be resolvable only by sending queries to the right
      server (e.g., intranet services).  Otherwise, a response with
      NXDOMAIN is replied.  Fast response is treated as optimal only if

Chen, et al.              Expires May 17, 2017                 [Page 10]

Internet-Draft             happy-eyeballs-mif              November 2016

      the record is valid.  That may cause messy for data connections,
      since NXDOMAIN doesn't provide useful information.

   HE-MIF can help to solve the issues of DNS interception with captive
   portal.  The DNS server modified and replied the answer with the IP
   address of captive portal rather than the intended destination
   address.  In those cases, TCP connection may succeed, but Internet
   connectivity is not available.  It results in lack of service unless
   user has authenticated.  HE-MIF recommended using network
   connectivity status probes to examine a pre-configured URL for
   detecting DNS interception on the path (see more in Section 5.2).
   The node will be able to automatically rely upon other interfaces to
   select right DNS servers by excluding the unexamined interfaces.

7.4.  Flow Continuity

   [I-D.deng-mif-api-session-continuity-guide] describes session
   continuity guidance for application developers.  The flow continuity
   topic is beyond this document scope.

7.5.  Interworking with Happy Eyeball

   HE-MIF process could cooperate with HE [RFC6555].  HE is executed on
   an interface which is selected to make connection establishment (see
   Section 5.2.3).  for example, a node following PvD policy to pick a
   interface and make both IPv4/IPv6 connection attempts in consistent
   with HE requirements.  The interface state management in HE-MIF is
   designed to synchronize with IP family states.  It could facilitate
   the HE executions.

7.6.  Multipath Applicability

   Some nodes may support transports that provide an abstraction of a
   single connection, aggregating multiple underlying connections.
   Multipath TCP (MPTCP) [RFC6182] is an example of such a transport
   protocol.  For connections provided by such transports, a node may
   leverage the "happiness" parameters and process on the underlying
   connections.  Following the HE-MIF requirements, each connection
   could be performed consistently with user/operator's preference and
   corresponding provisioning domain information.

8.  IANA Considerations

   This memo does not include any IANA requests.

Chen, et al.              Expires May 17, 2017                 [Page 11]

Internet-Draft             happy-eyeballs-mif              November 2016

9.  Security Considerations

   The security consideration is following the statement in [RFC6555]
   and [RFC6418].

10.  Acknowledgements

   The authors would like to thank Margaret Wasserman, Hui Deng, Erik
   Kline, Stuart Cheshire, Teemu Savolainen, Jonne Soininen, Simon
   Perreault, Zhen Cao, Dmitry Anipko, Ted Lemon, Daniel Migault, Russ
   White and Bing Liu for their helpful comments.

   Many thanks to Ralph Droms, Ian Farrer, Jouni Korhonen, Mirja
   Khlewind and Suresh Krishnan for their detailed reviews.

11.  References

11.1.  Normative References

   [RFC1122]  Braden, R., Ed., "Requirements for Internet Hosts -
              Communication Layers", STD 3, RFC 1122,
              DOI 10.17487/RFC1122, October 1989,

   [RFC4191]  Draves, R. and D. Thaler, "Default Router Preferences and
              More-Specific Routes", RFC 4191, DOI 10.17487/RFC4191,
              November 2005, <>.

   [RFC6555]  Wing, D. and A. Yourtchenko, "Happy Eyeballs: Success with
              Dual-Stack Hosts", RFC 6555, DOI 10.17487/RFC6555, April
              2012, <>.

   [RFC6724]  Thaler, D., Ed., Draves, R., Matsumoto, A., and T. Chown,
              "Default Address Selection for Internet Protocol Version 6
              (IPv6)", RFC 6724, DOI 10.17487/RFC6724, September 2012,

   [RFC6731]  Savolainen, T., Kato, J., and T. Lemon, "Improved
              Recursive DNS Server Selection for Multi-Interfaced
              Nodes", RFC 6731, DOI 10.17487/RFC6731, December 2012,

              3rd Generation Partnership Project, 3GPP., "Architecture
              enhancements for non-3GPP accesses v8.8.0", December 2009.

Chen, et al.              Expires May 17, 2017                 [Page 12]

Internet-Draft             happy-eyeballs-mif              November 2016

              3rd Generation Partnership Project, 3GPP., "Access to the
              3GPP Evolved Packet Core (EPC) via non-3GPP access
              networks v14.0.0", June 2016.

11.2.  Informative References

              Deng, H., Krishnan, S., Lemon, T., and M. Wasserman,
              "Guide for application developers on session continuity by
              using MIF API", draft-deng-mif-api-session-continuity-
              guide-04 (work in progress), July 2014.

              Liu, D., Lemon, T., Ismailov, Y., and Z. Cao, "MIF API
              consideration", draft-ietf-mif-api-extension-05 (work in
              progress), February 2014.

              Krishnan, S., Korhonen, J., and S. Bhandari, "Support for
              multiple provisioning domains in DHCPv6", draft-ietf-mif-
              mpvd-dhcp-support-02 (work in progress), October 2015.

              Krishnan, S., Korhonen, J., Bhandari, S., and S.
              Gundavelli, "Identification of provisioning domains",
              draft-ietf-mif-mpvd-id-02 (work in progress), October

              Korhonen, J., Krishnan, S., and S. Gundavelli, "Support
              for multiple provisioning domains in IPv6 Neighbor
              Discovery Protocol", draft-ietf-mif-mpvd-ndp-support-03
              (work in progress), February 2016.

   [RFC5461]  Gont, F., "TCP's Reaction to Soft Errors", RFC 5461,
              DOI 10.17487/RFC5461, February 2009,

   [RFC6182]  Ford, A., Raiciu, C., Handley, M., Barre, S., and J.
              Iyengar, "Architectural Guidelines for Multipath TCP
              Development", RFC 6182, DOI 10.17487/RFC6182, March 2011,

   [RFC6418]  Blanchet, M. and P. Seite, "Multiple Interfaces and
              Provisioning Domains Problem Statement", RFC 6418,
              DOI 10.17487/RFC6418, November 2011,

Chen, et al.              Expires May 17, 2017                 [Page 13]

Internet-Draft             happy-eyeballs-mif              November 2016

   [RFC6419]  Wasserman, M. and P. Seite, "Current Practices for
              Multiple-Interface Hosts", RFC 6419, DOI 10.17487/RFC6419,
              November 2011, <>.

   [RFC7556]  Anipko, D., Ed., "Multiple Provisioning Domain
              Architecture", RFC 7556, DOI 10.17487/RFC7556, June 2015,

Authors' Addresses

   Gang Chen
   China Mobile
   29, Jinrong Avenue
   Xicheng District,
   Beijing  100033


   Carl Williams
   El Camino Real
   Palo Alto, CA  94306


   Dan Wing
   Cisco Systems, Inc.
   170 West Tasman Drive
   San Jose, CA  95134


   Andrew Yourtchenko
   Cisco Systems, Inc.
   De Kleetlaan, 7
   Diegem  B-1831


Chen, et al.              Expires May 17, 2017                 [Page 14]