1. RFC 7086
Internet Engineering Task Force (IETF)                        A. Keranen
Request for Comments: 7086                                  G. Camarillo
Category: Experimental                                        J. Maenpaa
ISSN: 2070-1721                                                 Ericsson
                                                            January 2014

 Host Identity Protocol-Based Overlay Networking Environment (HIP BONE)
  Instance Specification for REsource LOcation And Discovery (RELOAD)


   This document is the HIP-Based Overlay Networking Environment (HIP
   BONE) instance specification for the REsource LOcation And Discovery
   (RELOAD) protocol.  The document provides the details needed to build
   a RELOAD-based overlay that uses HIP.

Status of This Memo

   This document is not an Internet Standards Track specification; it is
   published for examination, experimental implementation, and

   This document defines an Experimental Protocol for the Internet
   community.  This document is a product of the Internet Engineering
   Task Force (IETF).  It represents the consensus of the IETF
   community.  It has received public review and has been approved for
   publication by the Internet Engineering Steering Group (IESG).  Not
   all documents approved by the IESG are a candidate for any level of
   Internet Standard; see Section 2 of RFC 5741.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at

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Copyright Notice

   Copyright (c) 2014 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
   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
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Peer Protocol . . . . . . . . . . . . . . . . . . . . . . . .   3
   4.  Node ID Generation  . . . . . . . . . . . . . . . . . . . . .   3
   5.  Mapping between Protocol Primitives and HIP Messages  . . . .   3
     5.1.  Forwarding Header . . . . . . . . . . . . . . . . . . . .   4
     5.2.  Security Block  . . . . . . . . . . . . . . . . . . . . .   4
     5.3.  Replaced RELOAD Messages  . . . . . . . . . . . . . . . .   5
   6.  Securing Communication  . . . . . . . . . . . . . . . . . . .   5
   7.  Routing HIP Messages via the Overlay  . . . . . . . . . . . .   5
   8.  Enrollment and Bootstrapping  . . . . . . . . . . . . . . . .   6
   9.  NAT Traversal . . . . . . . . . . . . . . . . . . . . . . . .   7
   10. RELOAD Overlay Configuration Document Extension . . . . . . .   7
   11. Security Considerations . . . . . . . . . . . . . . . . . . .   8
   12. IANA Considerations . . . . . . . . . . . . . . . . . . . . .   8
   13. Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   8
   14. References  . . . . . . . . . . . . . . . . . . . . . . . . .   8
     14.1.  Normative References . . . . . . . . . . . . . . . . . .   8
     14.2.  Informative References . . . . . . . . . . . . . . . . .   9

1.  Introduction

   The HIP-Based Overlay Networking Environment (HIP BONE) specification
   [RFC6079] provides a high-level framework for building HIP-based
   [RFC5201] overlays.  The HIP BONE framework does not address the
   specification of the details on how to combine a particular peer
   protocol with HIP to build an overlay.  It leaves this up to
   documents referred to as HIP BONE instance specifications.  As
   discussed in [RFC6079], a HIP BONE instance specification needs to
   define, minimally:

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   o  the peer protocol to be used.

   o  what kind of Node IDs are used and how they are derived.

   o  which peer protocol primitives trigger HIP messages.

   o  how the overlay identifier is generated.

   This document addresses all the previous items and provides
   additional details needed to build RELOAD-based HIP BONEs, referred
   to here as RELOAD HIP BONEs.  The details on how different RELOAD
   modules would be integrated to a HIP implementation and what kind of
   APIs are used between them are left as implementation details or to
   be defined by other documents.

2.  Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   document are to be interpreted as described in [RFC2119].  In
   addition, this document uses the terms defined in [RFC5201],
   [RFC6079], [RFC6028], and [RFC6940].

3.  Peer Protocol

   The peer protocol to be used is REsource LOcation And Discovery
   (RELOAD) [RFC6940].  When used with RELOAD, HIP replaces the RELOAD's
   Forwarding and Link Management Layer (described in Section 6.5 of

4.  Node ID Generation

   This document specifies two modes for generating Node and Resource
   IDs.  Which mode is used in an actual overlay is defined by the
   overlay configuration.  Both of the modes are based on 16-byte ID
   mode of RELOAD; hence, only 16-byte RELOAD Node and Resource IDs MUST
   be used in a RELOAD HIP BONE.

   HIP uses 128-bit Overlay Routable Cryptographic Hash Identifiers
   (ORCHIDs) [RFC4843] as identifiers.  In a RELOAD HIP BONE, a peer's
   ORCHID can be used as a RELOAD Node ID (the "ORCHID" mode).  In this
   mode, all the RELOAD IDs, including Resource IDs, are prefixed with
   the ORCHID prefix, and the lower 100 bits of the IDs defined by
   RELOAD usage documents are used after the prefix.

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   In the other Node ID mode, namely "RELOAD", all 128 bits are
   generated as defined in [RFC6940].  This results in a larger usable
   address space than using the ORCHID mode, but the resulting Node IDs
   cannot be used with legacy applications and APIs, as discussed in
   Section 5.1 of [RFC6079].

5.  Mapping between Protocol Primitives and HIP Messages

   RELOAD HIP BONE replaces the RELOAD protocol primitives taking care
   of connection establishment with the HIP base exchange, whereas the
   rest of the RELOAD messages are conveyed within HIP messages.  The
   Forwarding and Link Management Layer functionality of RELOAD,
   including all the NAT traversal functionality, is replaced by HIP,
   existing extensions of HIP, and the extensions defined in this

   The standard RELOAD messages consist of three parts: the forwarding
   header, the message contents, and the security block.  When RELOAD
   messages are sent in a RELOAD HIP BONE overlay, the RELOAD message
   contents are used as such within HIP DATA [RFC6078] messages, but the
   functionality of the forwarding header and security block are
   replaced with the HIP header, HIP Destination and Via lists
   [RFC6028], CERT [RFC6253], TRANSACTION_ID [RFC6078], and the
   OVERLAY_ID and OVERLAY_TTL [RFC6079] parameters, as defined in the
   following sections.

5.1.  Forwarding Header

   The RELOAD forwarding header is used for forwarding messages between
   peers and to their final destination.  The forwarding header's
   overlay field value MUST be used as such in an OVERLAY_ID parameter
   and the transaction_id field in a TRANSACTION_ID parameter.  That is,
   all RELOAD HIP BONE messages MUST contain these parameters; and, the
   length of the OVERLAY_ID parameter's identifier field is 4, and the
   length of the TRANSACTION_ID parameter is 8 octets.  HIP Destination
   and Via lists are used for the same purpose as the destination_list
   and via_list in the forwarding header, with the exception that all
   Resource IDs MUST be of the same length as Node IDs, and compressed
   IDs MUST NOT be used.  The Time to Live (TTL) value in the
   OVERLAY_TTL parameter is used like the ttl field in the forwarding

   The functionality of the fragment and length fields are provided by
   the HIP headers.  The relo_token, version, and max_response_length
   are not needed with HIP.  The forwarding header's options field, if
   needed eventually for some extensions, can be substituted with
   additional HIP parameters.

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5.2.  Security Block

   The RELOAD security block contains certificates and digital
   signatures of the message.  All the HIP DATA messages are digitally
   signed by the originator of the message and contain the HOST_ID
   parameter with the identifier that can be used for verifying the
   signature.  Certificates are delivered in a HIP CERT parameter as
   defined in [RFC6253] or stored to the overlay using the RELOAD
   Certificate Storage Usage.

   Note that when the RELOAD mode for Node ID generation is used, the
   certificate certifying that a host is allowed to use a certain Node
   ID MUST contain the host's Node ID instead of the Host Identity Tag
   (HIT) in the "subjectAltName" field of the certificate as described
   in Section 11.3 of [RFC6940], while the "Subject" field contains the
   HIT calculated from the Host Identity.

5.3.  Replaced RELOAD Messages

   The Attach procedure in RELOAD establishes a connection between two
   peers.  This procedure is performed using the AttachReq and AttachAns
   messages.  When HIP is used, the Attach procedure is performed by
   using a HIP base exchange.  That is, peers send HIP first Initiator
   (I1) messages instead of RELOAD AttachReq messages.  This behavior
   replaces the one described in Section 6.5 of [RFC6940].

   The AppAttach procedure in RELOAD is used for creating a connection
   for other applications than RELOAD.  Also, the AppAttach procedure is
   replaced with the HIP base exchange, and after the base exchange,
   peers can exchange any application layer data using the normal
   transport layer ports over the NAT traversing IPsec connection.

   This specification does not support flooding of configuration files,
   so ConfigUpdate requests and responses (Section 6.5.4 of [RFC6940])
   MUST NOT be sent in the overlay.  RELOAD Ping messages (Section 6.5.3
   of [RFC6940]) MAY be used.

   For all other RELOAD messages, the message contents are used as such
   within HIP DATA messages.

6.  Securing Communication

   RELOAD uses Transport Layer Security (TLS) [RFC5246] connections for
   securing the hop-by-hop messaging and certificates and signatures for
   providing integrity protection for the overlay messages and for the
   data stored in the overlay.

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   With a RELOAD HIP BONE, instead of using TLS connections as defined
   in [RFC6940], all HIP overlay messages MUST be sent using encrypted
   connections [RFC6261].

   The data objects stored in the RELOAD HIP BONE overlay are signed,
   and the signatures are stored as defined in [RFC6940] with the
   exception that SignerIdentity is carried in the HIP DATA message's
   HOST_ID parameter instead of using the RELOAD security block.  Where
   certificates are needed, they are sent using the HIP CERT parameter.

7.  Routing HIP Messages via the Overlay

   If a host has no valid locator for the receiver of a new HIP packet,
   and the receiver is part of a RELOAD HIP BONE overlay the host is
   participating in, the host can send the HIP packet to the receiver
   using the overlay routing.

   When sending a HIP packet via the overlay, the host MUST add an empty
   ROUTE_VIA parameter [RFC6028] to the packet with the SYMMETRIC and
   MUST_FOLLOW flags set and an OVERLAY_ID parameter containing the
   identifier of the right overlay network.  The host consults the
   RELOAD Topology Plugin for the next hop and sends the HIP packet to
   that host.

   An intermediate host receiving a HIP packet with the OVERLAY_ID
   parameter checks if it is participating in that overlay and SHOULD
   drop packets sent to unknown overlays.  If the host is not the final
   destination of the packet (i.e., the Receiver HIT in the HIP header
   does not match to any of its HITs), it checks if the packet contains
   a ROUTE_DST parameter.  Such packets are forwarded to the next hop as
   specified in [RFC6028].  If the packet does not contain a ROUTE_DST
   parameter, the host finds the next hop from the RELOAD Topology
   Plugin and forwards the packet there.  As specified in [RFC6028], the
   host adds the HIT it uses on the HIP association with the next-hop
   host to the end of the ROUTE_VIA parameter, if present.

   When the final destination host receives the HIP packet, the host
   processes it as specified in [RFC5201]; and, if the packet is a HIP
   DATA packet, the contents are processed as specified in [RFC6940].
   If the HIP packet generates a response, the response is routed back
   on the same path using the ROUTE_DST parameter as specified in

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8.  Enrollment and Bootstrapping

   The RELOAD HIP BONE instance uses the enrollment and bootstrap
   procedure defined by RELOAD [RFC6940] with the exceptions listed

   o  In RELOAD, a node wishing to enroll in an overlay starts with
      obtaining a configuration document as explained in [RFC6940].
      This specification extends the RELOAD overlay configuration
      document as defined in Section 10.

   o  The X.509 certificates used by the RELOAD HIP BONE instance are
      similar to those of RELOAD except that they contain HITs instead
      of RELOAD URIs.  The HITs are included in the SubjectAltName field
      of the certificate as described in [RFC6253].

   o  When contacting a bootstrap node, instead of forming a Datagram
      Transport Layer Security (DTLS) or TLS connection, the host MUST
      perform a HIP base exchange with the bootstrap node.  The base
      exchange MAY be performed using a HIP rendezvous or relay server.

9.  NAT Traversal

   RELOAD relies on the Forwarding and Link Management Layer providing
   NAT traversal capabilities.  Thus, the RELOAD HIP BONE instance
   implementations MUST implement some reliable NAT traversal mechanism.
   To maximize interoperability, all implementations SHOULD implement at
   least [RFC5770].

   HIP relay servers are not necessarily needed with this HIP BONE
   instance since the overlay network can be used for relaying the base
   exchange, and further HIP signaling can be done directly between the
   peers.  However, if it is possible that a bootstrap peer is behind a
   NAT, it MUST register with a HIP relay so that there is a reliable
   way to connect to it.

10.  RELOAD Overlay Configuration Document Extension

   This document modifies the bootstrap-node element of the RELOAD
   overlay configuration document.  The modified bootstrap-node element
   contains the following attributes:

   address:  The locator of the bootstrap node.

   port:  The HIP port of the bootstrap node.

   hit:  The HIT of the bootstrap node.

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   If the bootstrap-node element does not contain a HIT, the
   opportunistic mode (as specified in [RFC5201]) SHOULD be used for
   contacting the bootstrap node.  If the element does not contain a
   port number, the bootstrap node SHOULD be contacted by starting the
   base exchange as defined in [RFC5201].  Otherwise, the base exchange
   MUST be started with UDP encapsulation, as defined in [RFC5770],
   using the given port as the destination port number.

   A RELOAD HIP BONE overlay MUST use the Overlay Link Protocol type
   "HIP" in the configuration document's overlay-link-protocol element.
   The enrolling node MUST check the overlay-link-protocol element and
   proceed with procedures defined in this document only if the "HIP"
   link type is found.

   This document also adds a new element inside the configuration
   element that defines which mode (see Section 4) is used for
   generating the Node and Resource IDs.  The name of the element is
   "hipbone-id-mode" and the content is the identifier of the mode:
   "ORCHID" for the ORCHID prefixed IDs and "RELOAD" for the IDs that
   use the whole 128 bits as defined by the RELOAD specification.  The
   NodeIdLength MUST be set to 16 in the configuration document, and the
   16 bytes are used, depending on the generation mode, as defined in
   Section 4.

11.  Security Considerations

   The security considerations of RELOAD (Section 13 of [RFC6940]), with
   the exception of TLS-specific features, also apply to RELOAD HIP BONE

   Limiting the Node ID and Resource ID space into 128 bits (or 100 bits
   with ORCHID prefixes) results in a higher probability for ID
   collisions, both unintentional and intentional, than using larger
   address spaces.

12.  IANA Considerations

   This section is to be interpreted according to [RFC5226].

   IANA has updated the "RELOAD Overlay Link Protocol Registry"
   [RFC6940] by assigning the new Overlay Link Protocol type "HIP" (see
   Section 10).

13.  Acknowledgements

   Tom Henderson, Spencer Dawkins, and Christer Holmberg have provided
   valuable reviews and comments on the document.

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14.  References

14.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC4843]  Nikander, P., Laganier, J., and F. Dupont, "An IPv6 Prefix
              for Overlay Routable Cryptographic Hash Identifiers
              (ORCHID)", RFC 4843, April 2007.

   [RFC5201]  Moskowitz, R., Nikander, P., Jokela, P., and T. Henderson,
              "Host Identity Protocol", RFC 5201, April 2008.

   [RFC5226]  Narten, T. and H. Alvestrand, "Guidelines for Writing an
              IANA Considerations Section in RFCs", BCP 26, RFC 5226,
              May 2008.

   [RFC5770]  Komu, M., Henderson, T., Tschofenig, H., Melen, J., and A.
              Keranen, "Basic Host Identity Protocol (HIP) Extensions
              for Traversal of Network Address Translators", RFC 5770,
              April 2010.

   [RFC6028]  Camarillo, G. and A. Keranen, "Host Identity Protocol
              (HIP) Multi-Hop Routing Extension", RFC 6028, October

   [RFC6078]  Camarillo, G. and J. Melen, "Host Identity Protocol (HIP)
              Immediate Carriage and Conveyance of Upper-Layer Protocol
              Signaling (HICCUPS)", RFC 6078, January 2011.

   [RFC6079]  Camarillo, G., Nikander, P., Hautakorpi, J., Keranen, A.,
              and A. Johnston, "HIP BONE: Host Identity Protocol (HIP)
              Based Overlay Networking Environment (BONE)", RFC 6079,
              January 2011.

   [RFC6253]  Heer, T. and S. Varjonen, "Host Identity Protocol
              Certificates", RFC 6253, May 2011.

   [RFC6261]  Keranen, A., "Encrypted Signaling Transport Modes for the
              Host Identity Protocol", RFC 6261, May 2011.

   [RFC6940]  Jennings, C., Lowekamp, B., Rescorla, E., Baset, S., and
              H. Schulzrinne, "REsource LOcation And Discovery (RELOAD)
              Base Protocol", January 2014.

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14.2.  Informative References

   [RFC5246]  Dierks, T. and E. Rescorla, "The Transport Layer Security
              (TLS) Protocol Version 1.2", RFC 5246, August 2008.

Authors' Addresses

   Ari Keranen
   Hirsalantie 11
   02420 Jorvas

   EMail: Ari.Keranen@ericsson.com

   Gonzalo Camarillo
   Hirsalantie 11
   Jorvas  02420

   EMail: Gonzalo.Camarillo@ericsson.com

   Jouni Maenpaa
   Hirsalantie 11
   Jorvas  02420

   EMail: Jouni.Maenpaa@ericsson.com

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  1. RFC 7086