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IDR                                                      G. Van de Velde
Internet-Draft
Intended status: Standards Track                                K. Patel
Expires: September 10, 2015                                       D. Rao
                                                           Cisco Systems
                                                               R. Raszuk
                                                            NTT MCL Inc.
                                                                 R. Bush
                                               Internet Initiative Japan
                                                           March 9, 2015


                          BGP Remote-Next-Hop
                draft-vandevelde-idr-remote-next-hop-09

Abstract

   The BGP Remote-Next-Hop attribute is an optional transitive attribute
   intended to facilitate automatic tunnelling across an AS for an NLRI
   in a given address family.  The attribute carries one or more tunnel
   end-points and associated tunnel encapsulation information for a
   NLRI.

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 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 September 10, 2015.

Copyright Notice

   Copyright (c) 2015 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



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   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  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Requirements Language . . . . . . . . . . . . . . . . . . . .   3
   3.  Remote-Next-Hop Attribute . . . . . . . . . . . . . . . . . .   3
     3.1.  Tunnel Encapsulation attribute versus BGP Remote-Next-Hop
           attribute . . . . . . . . . . . . . . . . . . . . . . . .   4
   4.   BGP Remote-Next-Hop attribute TLV Format . . . . . . . . . .   4
   5.  Encapsulation sub-TLVs for virtual network overlays . . . . .   5
     5.1.  Encapsulation sub-TLV for VXLAN . . . . . . . . . . . . .   6
     5.2.  Encapsulation sub-TLV for NVGRE . . . . . . . . . . . . .   7
     5.3.  Encapsulation sub-TLV for GTP . . . . . . . . . . . . . .   8
     5.4.  Encapsulation for MPLS-in-GRE . . . . . . . . . . . . . .   8
   6.  Remote-Next-Hop Bestpath Considerations . . . . . . . . . . .   9
   7.  Securing Remote-Next-Hop  . . . . . . . . . . . . . . . . . .   9
     7.1.  Restrictions on Announcing of Remote-Next-Hop Attribute .  10
     7.2.  Restrictions on Originating of Remote-Next-Hop Attribute   10
   8.  Multiple tunnel endpoint addresses  . . . . . . . . . . . . .  11
   9.  Attribute error handling  . . . . . . . . . . . . . . . . . .  11
   10. BGP speakers that do not support BGP Remote-Next-Hop
       attribute . . . . . . . . . . . . . . . . . . . . . . . . . .  11
   11. Use Case scenarios  . . . . . . . . . . . . . . . . . . . . .  11
     11.1.  Stateless user-plane architecture for virtualized EPC
            (vEPC) . . . . . . . . . . . . . . . . . . . . . . . . .  12
     11.2.  Stateless User-plane Architecture for virtual Packet
            Edge . . . . . . . . . . . . . . . . . . . . . . . . . .  12
     11.3.  Dynamic Network Overlay Infrastructure . . . . . . . . .  12
     11.4.  Simple VPN solution using Multi-point Security
            Association  . . . . . . . . . . . . . . . . . . . . . .  12
   12. IANA Considerations . . . . . . . . . . . . . . . . . . . . .  13
   13. Security Considerations . . . . . . . . . . . . . . . . . . .  13
   14. Privacy Considerations  . . . . . . . . . . . . . . . . . . .  14
   15. Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  14
   16. Change Log  . . . . . . . . . . . . . . . . . . . . . . . . .  14
   17. References  . . . . . . . . . . . . . . . . . . . . . . . . .  14
     17.1.  Normative References . . . . . . . . . . . . . . . . . .  14
     17.2.  Informative References . . . . . . . . . . . . . . . . .  15
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  16






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1.  Introduction

   [RFC5512] defines an attribute attached to an NLRI to signal tunnel
   end-point encapsulation information between two BGP speakers for a
   single tunnel.  [RFC5512] requires that a new address-family needs to
   be enabled between the two BGP speakers.  It also assumes that the
   exchanged tunnel endpoint is the NLRI.

   This document defines a new BGP transitive attribute known as a
   Remote-Next-Hop BGP attribute for Intra-AS and Inter-AS usage, and
   simplifies the exchange and operations involved with tunnel end-point
   information propagation between two BGP speakers.

   The tunnel endpoint information and the tunnel encapsulation
   information is carried within a Remote-Next-Hop BGP attribute.  This
   attribute can be added to any BGP NLRI.  This way the Address Family
   (AF) of the NLRI exchanged is decoupled from the tunnel SAFI address-
   family defined in [RFC5512].  Multiple Remote-Next-Hop attribute TLVs
   can be added to a single NLRI.

   Security measures SHOULD be taken to protect against accidental or
   malicious tampering of the Remote-Next-Hop attribute.

2.  Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" are to
   be interpreted as described in [RFC2119] only when they appear in all
   upper case.  They may also appear in lower or mixed case as English
   words, without any normative meaning.

3.  Remote-Next-Hop Attribute

   There are an increasing number of use cases where the exchange of
   multiple unique tunnel endpoints and associated tunnel data is
   desired for a prefix using segments of an existing infrastructure,
   where requiring a new address-family to be enabled would add
   operational complexity.

   The BGP Remote-Next-Hop attribute is defined to be attached to each
   originated BGP NLRI in any applicable address-family.  Multiple
   Remote-Next-Hop attribute TLVs can be applied to a single originated
   BGP NLRI.  Each TLV can contain one or more sub-TLVs that carry
   encapsulation information.  Thus, it enables a simple mechanism to
   signal multiple, unique tunnel endpoints for a given prefix; as well
   as multiple encapsulation parameters for prefixes with the same
   remote tunnel end-point.




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   BGP Remote-Next-Hop attribute is a Transitive Optional BGP attribute,
   allowing to signal next-hop encapsulation parameters in a transitive
   manner without the requirement to enable a new address-family.

   This document specifies the tunnel types that can be used with this
   attribute.  The sub-TLVs from [RFC5512] and BGP IPsec tunnel
   encapsulation [RFC5566] are reused for the BGP Next-Hop-Attribute.

3.1.  Tunnel Encapsulation attribute versus BGP Remote-Next-Hop
      attribute

   The use of Tunnel Encapsulation attribute [RFC5512] is based on the
   principle that the tunnel end-point is carried as part of BGP NLRI in
   an Encapsulation SAFI.

   This requires enabling of the Encapsulation SAFI within a BGP enabled
   network.  It also sets up an interdependency between BGP routes in
   different SAFIs and the BGP Tunnel SAFI for resolving tunnel next-
   hops.

   The Encapsulation SAFI [RFC5512] assumes that the tunnel endpoint is
   the NLRI exchanged in the Encaps SAFI, while Remote-Next-Hop
   decouples the exchanged NLRI from the tunnel end-point information,
   thereby requiring mutual exclusive usage of the two mechanisms.

   While [RFC5512] allows multiple tunnel endpoints and multiple tunnel
   types to be carried within a BGP Encaps SAFI, the correlation of
   Tunnel information with other SAFIs is done using the color extended
   community which is also non-trivial.

4.  BGP Remote-Next-Hop attribute TLV Format

   This attribute is an optional transitive attribute [RFC1771].

   The BGP Remote-Next-Hop attribute is composed of a set of Type-
   Length-Value (TLV) encodings.  The type code of the attribute is
   (IANA to assign).  Each TLV contains information corresponding to a
   particular tunnel end-point address.

   0                   1                   2                   3
   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   Tunnel Type (2 Octets)    |              Length             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | Addr len    |     Tunnel Address (IPv4 or IPv6)               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                          AS Number                            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+



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   |                   Tunnel Parameters                           |
   ~                                                               ~
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


   Tunnel Type (2 octets): identifies the type of tunneling technology
   being signaled.  This document specifies the following types:

   - L2TPv3 over IP [RFC3931]: Tunnel Type = 1
   - GRE [RFC2784]: Tunnel Type = 2
   - Transmit tunnel endpoint [RFC5566]: Tunnel Type = 3
   - IPsec in Tunnel-mode [RFC5566]: Tunnel Type = 4
   - IP in IP tunnel
           with IPsec Transport Mode [RFC5566]: Tunnel Type = 5
   - MPLS-in-IP tunnel
           with IPsec Transport Mode [RFC5566]: Tunnel Type = 6
   - IP in IP [RFC2003] [RFC4213]: Tunnel Type = 7

   This document defines the following types:
   - VXLAN: Tunnel Type = 8
   - NVGRE: Tunnel Type = 9
   - GTP: Tunnel Type = 10
   - MPLS-in-GRE: Tunnel Type = 11
   - MPLS-in-UDP: Tunnel Type = 12
   - MPLS-in-UDP-with-DTLS: Tunnel Type = 13

   Unknown types MUST be ignored and skipped upon receipt.

   Length (2 octets): the total number of octets of the value field.

   Tunnel Address Length (1 octet): Length of Tunnel
   Address. Set to 4 bytes for an IPv4 address and 16 bytes for an
   IPv6 address.

   AS Number (4 octets): The AS number originating the BGP Remote-Next-Hop
   attribute and is either a 2-byte AS or 4-Byte AS number

   Tunnel Parameter (variable): comprised of multiple sub-TLVs.
   Each sub-TLV consists of three fields: a 1-octet type, 1-octet
   length, and zero or more octets of value.

5.  Encapsulation sub-TLVs for virtual network overlays

   A VN-ID may need to be signaled along with the encapsulation types
   for DC overlay encapsulations such as [VXLAN] and [NVGRE].  The VN-ID
   when present in the encapsulation sub-TLV for an overlay
   encapsulation, MUST be processed by a receiving device if it is
   capable of understanding it.  The details regarding how such a



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   signaled VN-ID is processed and used is defined in specifications
   such as [IPVPN-overlay] and [EVPN-overlay].

5.1.  Encapsulation sub-TLV for VXLAN

   This document defines a new encapsulation sub-TLV format, defined in
   [RFC5512], for VXLAN tunnels.  When the tunnel type is VXLAN, the
   following is the structure of the value field in the encapsulation
   sub-TLV:


   0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |V|M|R|R|R|R|R|R|          VN-ID (3 Octets)                   |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                 MAC Address (4 Octets)                      |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |  MAC Address (2 Octets)     |   Reserved                    |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


    V: When set to 1, it indicates that a valid VN-ID is present in the
    encapsulation sub-TLV.
    M: When set to 1, it indicates that a valid MAC Address is present
    in the encapsulation sub-TLV.
    R: The remaining bits in the 8-bit flags field are reserved for
    further use. They MUST be set to 0 on transmit and MUST be ignored
    on receipt.

    VN-ID: Contains a 3 octets VN-ID value, if the 'V' flag bit is set.
    If the 'V' flag is not set, it SHOULD be set to zero and MUST be
    ignored on receipt.

    The VN-ID value is filled in the VNI field in the VXLAN packet
    header as defined in [VXLAN].

    MAC Address: Contains a 6 octets of an Ethernet MAC address if the 'M' flag bit
    is set. If the 'M' flag is not set, it SHOULD set to all zeroes and
    MUST be ignored on receipt.

    The MAC address is local to the device advertising the route, and
    should be included as the destination MAC address in the inner
    Ethernet header immediately following the outer VXLAN header, in
    the packets destined to the advertiser.






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5.2.  Encapsulation sub-TLV for NVGRE

   This document defines a new encapsulation sub-TLV format, defined in
   [RFC5512], for NVGRE tunnels.  When the tunnel type is NVGRE, the
   following is the structure of the value field in the encapsulation
   sub-TLV:


   0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |V|M|R|R|R|R|R|R|          VN-ID (3 Octets)                   |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                 MAC Address (4 Octets)                      |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |  MAC Address (2 Octets)     |   Reserved                    |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

    V: When set to 1, it indicates that a valid VN-ID is present in the
    encapsulation sub-TLV.
    M: When set to 1, it indicates that a valid MAC Address is present
    in the encapsulation sub-TLV.
    R: The remaining bits in the 8-bit flags field are reserved for
    further use. They MUST be set to 0 on transmit and MUST be ignored
    on receipt.

    VN-ID: Contains a 3 octets VN-ID value, if the 'V' flag bit is set.
    If the 'V' flag is not set, it SHOULD be set to zero and MUST be
    ignored on receipt.

    The VN-ID value is filled in the VSID field in the NVGRE packet
    header as defined in [NVGRE].

    MAC Address: Contains a 6 octets of an Ethernet MAC address if the 'M' flag bit is
    set. If the 'M' flag is not set, it SHOULD set to all zeroes and
    MUST be ignored on receipt.

    The MAC address is local to the device advertising the route, and
    should be included as the destination MAC address in the inner
    Ethernet header immediately following the outer NVGRE header, in
    the packets destined to
    the advertiser.









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5.3.  Encapsulation sub-TLV for GTP

   This document defines a new encapsulation sub-TLV format, defined in
   [RFC5512], for GTP tunnels.  When the tunnel type is GTP, the
   following is the structure of the value field in the encapsulation
   sub-TLV:


      0                   1                   2                   3
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                    Local TEID (4 Octets)                    |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |       Local Endpoint Address (4/16 Octets (IPv4/IPv6))      |
       .                                                             .
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


       Local TEID: Contains a 32-bit Tunnel Endpoint Identifier of a
       GTP tunnel assigned by EPC that is used to distinguish different
       connections in received packets within the tunnel.

       Local Endpoint Address: Indicates a 4-octets IPv4 address or
       16-octets IPv6 address as a local endpoint address of GTP tunnel.

       Local Endpoint Address element makes a tunnel endpoint router
       allow to have multiple Local TEID spaces. Received GTP packets
       are identified which tunnel connection by combination of Local
       Endpoint Address and Local TEID.


5.4.  Encapsulation for MPLS-in-GRE

   This document defines a new encapsulation sub-TLV format, defined in
   [RFC5512], for MPLS-in-GRE tunnels.  When the tunnel type is MPLS-in-
   GRE, the following is the structure of the value field in an optional
   encapsulation sub-TLV:














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   0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                     GRE-Key (4 Octets)                      |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


    GRE-Key: 4-octet field [RFC2890] that is generated by the
    advertising router.  The actual method by which the key is obtained
    is beyond the scope of this document.  The key is inserted into the
    GRE encapsulation header of the payload packets sent by ingress
    routers to the advertising router.  It is intended to be used for
    identifying extra context information about the received payload.
    Note that the key is optional. Unless a key value is being
    advertised, the MPLS-in-GRE encapsulation sub-TLV MUST NOT be
        present.

        Note that signaling a GRE tunnel-type with routes in a labeled SAFI
        may be sufficient to indicate to the receiver that it needs to send
        MPLS packets with that GRE encapsulation. However, a specific
        tunnel-type for MPLS-in-GRE is being defined in order to make
        this indication explicit to a receiver.

6.  Remote-Next-Hop Bestpath Considerations

   A BGP speaker SHOULD support a policy to enable the support for using
   BGP Remote Nexthop attribute.  An implementation that supports the
   BGP Remote-Next-Hop MUST use BGP Nexthop attribute information
   whenever BGP Remote-Next-Hop is not enabled.

   Traditionally a BGP speaker uses the IGP cost towards the BGP Next-
   Hop as a BGP path selection criteria.  However, when a BGP speaker is
   configured to use the BGP Remote-Next-Hop value, then it SHOULD use
   the IGP cost towards the IP address selected from the Remote-Next-Hop
   attribute.  When there are multiple such IP addresses that may be
   installed, it SHOULD use the worst IGP cost among them.

   Similarly, the speaker SHOULD also check that the IP address is
   reachable before considering that path eligible for bestpath.

7.  Securing Remote-Next-Hop

   The Remote-Next-Hop attribute provides a set of tunnel parameters.
   While the Remote-Next-Hop attribute has as goal to inform an intended
   recipient with these tunnel parameters, it is important to make sure
   that the attributes have not been tampered with and that they are
   restricted to the intended scope of distribution for secure
   operation.



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7.1.  Restrictions on Announcing of Remote-Next-Hop Attribute

   The Remote-Next-Hop attribute is used to carry an additional
   information (tunnel end-point, encapsulation type, etc).  It has a
   security value to contain the distribution of the Remote-Next-Hop
   attribute within its planned scope of distribution.  This scope could
   be, but is not limited to, a particular department, site,
   organization, across ASes within a same administration control or a
   global scope.

   To contain distribution of the Remote-Next-Hop attribute beyond its
   intended scope of applicability, attribute filtering MAY be deployed.
   The BGP speaker communicating to a speaker beyond the intended scope
   of the Remote-Next-Hop attribute SHOULD filter the attribute during
   the route announcements.

   To facilitate attribute filtering, an implementation that supports
   the BGP Remote-Next-Hop attribute MUST support a policy to (1) ignore
   the received attribute and (2) filter the attribute.

7.2.  Restrictions on Originating of Remote-Next-Hop Attribute

   A BGP Remote-Next-Hop attribute may be added to routes that belong to
   same Autonomous system as the tunnel endpoint address.
   Implementations SHOULD validate the following to ensure the validity
   of Remote-Next-Hop Attribute:

   (1) BGP Remote-Next-Hops Tunnel Endpoint and AS number association
   SHOULD be validated using BGP Origin Validation.

   (2) BGP Remote-Next-Hop Tunnel Endpoints underlay routes origin AS
   SHOULD be validated using BGP Origin Validation.  This AS number MUST
   be the same as the AS number carried within BGP Remote-Next-Hop
   attribute.

   (3) The origin AS of BGP Routes that carry BGP Remote-Next-Hop
   attribute SHOULD be validated using BGP Origin Validation.  This AS
   number MUST be same as the AS number carried within BGP Remote-Next-
   Hop attribute.

   If the above validation fails, the tunnel type SHOULD be considered
   as invalid.  This does not affect the validity of the others tunnels
   types carried within the Remote-Next-Hop Attribute.








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8.  Multiple tunnel endpoint addresses

   In some cases, a device may need to accept incoming traffic for a
   prefix via multiple different encapsulations, to support interactions
   with remote devices with disjoint capabilities.  Certain device
   implementations cannot support the use of the same IP address as
   local tunnel endpoint for multiple encapsulations.

   In certain cases, a device may need to signal an additional,
   alternate tunnel endpoint address, to be used by other devices only
   as a backup in certain failure conditions.

9.  Attribute error handling

   When receiving a BGP Update message containing a malformed Remote-
   Next-Hop attribute, the attribute MUST be quietly ignored and not
   passed along to other BGP peers. (see [draft-ietf-idr-error-
   handling], Section 7).  This is equivalent to the -attribute discard-
   action specified in [draft-ietf-idr-error-handling].  An
   implementation MAY log an error for further analysis.

   Note that a BGP Remote-Next-Hop attribute MUST NOT be considered to
   be malformed because it contains more than one TLV of a given type or
   because it contains TLVs of unknown types.

   If a BGP path attribute is received that has the Remote-Next-Hop
   attribute codepoint but does not have the transitive bit set, the
   attribute MUST be considered to be a malformed Remote-Next-Hop
   attribute and MUST be discarded as specified in this section.

10.  BGP speakers that do not support BGP Remote-Next-Hop attribute

   If a BGP Speaker does not support this attribute, and receives this
   attribute, then it follows the normal NLRI processing and BGP best
   path selection, and the resulting forwarding decision is used, as the
   attribute is optional.

11.  Use Case scenarios

   This section provides a brief overview of some use-cases for the BGP
   Remote-Next-Hop attribute.  Use of the BGP Remote-Next-Hop is not
   limited to the examples in this section.  Details regarding how the
   attribute is used are described in the respective solution drafts
   that are referenced where necessary.







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11.1.  Stateless user-plane architecture for virtualized EPC (vEPC)

   The full usage case of BGP Remote-Next-Hop regarding vEPC can be
   found in [vEPC], while [RFC6459] documents IPv6 in 3GPP EPS.

   3GPP introduces Evolved Packet Core (EPC) that is fully IP based
   mobile system for LTE and -advanced in their Release-8 specification
   and beyond.  Operators are now deploying EPC for LTE services and
   encounter rapid LTE traffic growth.  There are various activities to
   offload mobile traffic in 3GPP and IETF such as LIPA, SIPTO and DMM.
   The concept is similar that traffic of OTT (Over The Top) application
   is offloaded at entity that is closer to the mobile node (ex. eNodeB
   or closer anchor).

11.2.  Stateless User-plane Architecture for virtual Packet Edge

   With the emergence of the NfV technologies, different architectures
   are proposed for virtualized services.  These functions will normally
   run in the datacenter.  BGP remote-next-hop can be used to inject
   traffic into the virtualized services running in the datacenter using
   tunnels.  These tunnels can be signalled using BGP remote-next-hop.
   This facilitates a dynamic, simple and clean routing architecture.
   BGP Remote Next Hop can simplify the orchestration or provisioning
   layer by signalling the tunnel endpoint (virtual provider edge
   router) in combination with the encapsulation protocol.

   If this is used together with orchestrated traffic steering
   mechanisms (i.e.  BGP Flowspec) , it is possible to differentiate at
   application level, and forward each different traffic types towards
   the desired destination.

11.3.  Dynamic Network Overlay Infrastructure

   The BGP Remote-Next-Hop extension allows consistent signalling of
   tunnel encapsulations as needed by virtual network overlay solutions
   such as [I-D.drao-bgp-l3vpn-virtual-network-overlays] and
   [I-D.sd-l2vpn-evpn-overlay]

11.4.  Simple VPN solution using Multi-point Security Association

   [draft-yamaya-ipsecme-mpsa] describes the overlay network solution by
   utilizing dynamically established IPsec multi-point Security
   Association (SA) without individual connection.

   Multi-point SA technology provides the simplified mechanism of the
   Auto Discovery and Configuration function.  This is applicable for
   any IPsec tunnels such as IPv4 over IPv4, IPv4 over IPv6, IPv6 over
   IPv4 and IPv6 over IPv6.



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   MPSA does not provide peer discovery function by itself.  However,
   other mechanism, such as BGP, can be employed with MPSA for automatic
   peer discovery.  BGP Remote-Next-Hop can be used to learn peer
   information as next-hops.

12.  IANA Considerations

   This document defines a new BGP attribute known as a BGP Remote-Next-
   Hop attribute.  We request IANA to allocate a new attribute code from
   the -BGP Path Attributes- registry with a symbolic name -Remote-Next-
   Hop- attribute.

   We also request IANA to allocate four new BGP Tunnel Types from the
   -BGP Tunnel Encapsulation Attribute Tunnel Types- registry with the
   following symbolic names: -VXLAN- with Tunnel type 8, -NVGRE- with
   Tunnel type 9, -GTP- with Tunnel type 10, -MPLS-in-GRE with Tunnel
   type 11, -MPLS-in-UDP- with Tunnel type 12 and -MPLS-in-UDP-with-DTLS
   with Tunnel type 13.

13.  Security Considerations

   This technology could be used as technology as man in the middle
   attack, however with existing RPKI validation for BGP that risk is
   reduced.

   The distribution of Tunnel end-point address information can result
   in potential DoS attacks.  Therefore is it strongly recommended to
   install traffic filters, IDSs and IPSs at the perimeter of the
   tunneled network infrastructure.

   measures SHOULD be taken to protect the validity of the BGP Remote-
   Next-Hop attribute.  It is possible to inject a rogue BGP Remote-
   Next-Hop attribute to an NLRI resulting in Monkey-In-The-Middle
   attack (MITM).  To avoid this type of MITM attack, it is strongly
   recommended to use a technology mechanism to verify that for NLRI it
   is the expected BGP Remote-Next-Hop. We anticipate that this can be
   done with an expansion of RPKI-Based origin validation, see
   [I-D.ietf-sidr-pfx-validate].

   This does not avoid the fact that rogue AS numbers may be inserted or
   injected into the AS-Path.  To achieve protection against that threat
   BGP Path Validation should be used, see
   [I-D.ietf-sidr-bgpsec-overview].








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14.  Privacy Considerations

   This proposal may introduce privacy issues, however with BGP security
   mechanisms in place they should be prevented.

15.  Acknowledgements

   The authors would like to thanks Satoru Matsushima, Bruno Decraene,
   Ryuji Wakikawa and Miya Kohno for their usefull vEPC discussions.
   Istvan Kakonyi provided insight in the vPE use case scenario.

   Satoshi Usui provided datapoints around Simple VPN solution using
   Multi-point Security Association.

16.  Change Log

   Initial Version:  16 May 2012

   Hacked for -01:  17 July 2012

   Hacked for -05:  07 January 2014

   Hacked for -07:  15 September 2014

17.  References

17.1.  Normative References

   [I-D.ietf-mpls-in-udp]
              Xu, X., Sheth, N., Yong, L., Callon, R., and D. Black,
              "Encapsulating MPLS in UDP", draft-ietf-mpls-in-udp-11
              (work in progress), January 2015.

   [RFC1771]  Rekhter, Y. and T. Li, "A Border Gateway Protocol 4 (BGP-
              4)", RFC 1771, March 1995.

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

   [RFC2784]  Farinacci, D., Li, T., Hanks, S., Meyer, D., and P.
              Traina, "Generic Routing Encapsulation (GRE)", RFC 2784,
              March 2000.

   [RFC3484]  Draves, R., "Default Address Selection for Internet
              Protocol version 6 (IPv6)", RFC 3484, February 2003.

   [RFC3931]  Lau, J., Townsley, M., and I. Goyret, "Layer Two Tunneling
              Protocol - Version 3 (L2TPv3)", RFC 3931, March 2005.



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   [RFC4213]  Nordmark, E. and R. Gilligan, "Basic Transition Mechanisms
              for IPv6 Hosts and Routers", RFC 4213, October 2005.

   [RFC4271]  Rekhter, Y., Li, T., and S. Hares, "A Border Gateway
              Protocol 4 (BGP-4)", RFC 4271, January 2006.

   [RFC5512]  Mohapatra, P. and E. Rosen, "The BGP Encapsulation
              Subsequent Address Family Identifier (SAFI) and the BGP
              Tunnel Encapsulation Attribute", RFC 5512, April 2009.

   [RFC5566]  Berger, L., White, R., and E. Rosen, "BGP IPsec Tunnel
              Encapsulation Attribute", RFC 5566, June 2009.

   [RFC6459]  Korhonen, J., Soininen, J., Patil, B., Savolainen, T.,
              Bajko, G., and K. Iisakkila, "IPv6 in 3rd Generation
              Partnership Project (3GPP) Evolved Packet System (EPS)",
              RFC 6459, January 2012.

   [RFC7348]  Mahalingam, M., Dutt, D., Duda, K., Agarwal, P., Kreeger,
              L., Sridhar, T., Bursell, M., and C. Wright, "Virtual
              eXtensible Local Area Network (VXLAN): A Framework for
              Overlaying Virtualized Layer 2 Networks over Layer 3
              Networks", RFC 7348, August 2014.

17.2.  Informative References

   [I-D.drao-bgp-l3vpn-virtual-network-overlays]
              Rao, D., Mullooly, J., and R. Fernando, "Layer-3 virtual
              network overlays based on BGP Layer-3 VPNs", draft-drao-
              bgp-l3vpn-virtual-network-overlays-03 (work in progress),
              July 2014.

   [I-D.ietf-idr-error-handling]
              Chen, E., Scudder, J., Mohapatra, P., and K. Patel,
              "Revised Error Handling for BGP UPDATE Messages", draft-
              ietf-idr-error-handling-13 (work in progress), June 2014.

   [I-D.ietf-sidr-bgpsec-overview]
              Lepinski, M., "An Overview of BGPsec", draft-ietf-sidr-
              bgpsec-overview-06 (work in progress), January 2015.

   [I-D.ietf-sidr-pfx-validate]
              Mohapatra, P., Scudder, J., Ward, D., Bush, R., and R.
              Austein, "BGP Prefix Origin Validation", draft-ietf-sidr-
              pfx-validate-10 (work in progress), October 2012.






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   [I-D.matsushima-stateless-uplane-vepc]
              Matsushima, S. and R. Wakikawa, "Stateless user-plane
              architecture for virtualized EPC (vEPC)", draft-
              matsushima-stateless-uplane-vepc-01 (work in progress),
              July 2013.

   [I-D.sd-l2vpn-evpn-overlay]
              Sajassi, A., Drake, J., Bitar, N., Isaac, A., Uttaro, J.,
              and W. Henderickx, "A Network Virtualization Overlay
              Solution using EVPN", draft-sd-l2vpn-evpn-overlay-03 (work
              in progress), June 2014.

   [I-D.sridharan-virtualization-nvgre]
              Sridharan, M., Greenberg, A., Wang, Y., Garg, P.,
              Venkataramiah, N., Duda, K., Ganga, I., Lin, G., Pearson,
              M., Thaler, P., and C. Tumuluri, "NVGRE: Network
              Virtualization using Generic Routing Encapsulation",
              draft-sridharan-virtualization-nvgre-05 (work in
              progress), July 2014.

   [I-D.yamaya-ipsecme-mpsa]
              Yamaya, A., Ohya, T., Yamagata, T., and S. Matsushima,
              "Simple VPN solution using Multi-point Security
              Association", draft-yamaya-ipsecme-mpsa-04 (work in
              progress), July 2014.

Authors' Addresses

   Gunter Van de Velde

   Email: gunter@vandevelde.cc


   Keyur Patel
   Cisco Systems
   170 W. Tasman Drive
   San Jose, CA 95124  95134
   USA

   Email: keyupate@cisco.com











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   Dhananjaya Rao
   Cisco Systems
   170 W. Tasman Drive
   San Jose, CA 95124  95134
   USA

   Email: dhrao@cisco.com


   Robert Raszuk
   NTT MCL Inc.
   101 S Ellsworth Avenue Suite 350
   San Mateo, CA  94401
   US

   Email: robert@raszuk.net


   Randy Bush
   Internet Initiative Japan
   5147 Crystal Springs
   Bainbridge Island, Washington  98110
   US

   Email: randy@psg.com


























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