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BGP Path Record Attribute
draft-raszuk-idr-bgp-pr-00

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This is an older version of an Internet-Draft whose latest revision state is "Expired".
Author Robert Raszuk
Last updated 2014-07-23
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draft-raszuk-idr-bgp-pr-00
Network Working Group                                          R. Raszuk
Internet-Draft                                                Individual
Intended status: Standards Track                           July 23, 2014
Expires: January 24, 2015

                       BGP Path Record Attribute
                       draft-raszuk-idr-bgp-pr-00

Abstract

   BGP protocol today contains number of build in mechanisms which
   record critical for its loop free operation data along the path of
   BGP message propagation.  Those are encoded in AS_PATH, CLUSTER_LIST
   or ORIGINATOR_ID attributes.  However in the same time there is no
   provisioning to record other useful information along the path which
   can be helpful to the operator in order to enhance end to end
   visibility of BGP control plane.

   In order to solve this problem this document proposes a new single
   BGP attribute designed as an generic and extensible container to
   carry number of new optional information corresponding to the BGP
   speakers given BGP advertisement (or withdraw) message traverses.

Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119 [RFC2119].

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 January 24, 2015.

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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.  Protocol Extensions . . . . . . . . . . . . . . . . . . . . .   3
     2.1.  BGP Path Record Attribute . . . . . . . . . . . . . . . .   3
     2.2.  BGP Hop TLV . . . . . . . . . . . . . . . . . . . . . . .   4
       2.2.1.  Host Name sub-TLV . . . . . . . . . . . . . . . . . .   6
       2.2.2.  Time Stamp sub-TLV  . . . . . . . . . . . . . . . . .   6
       2.2.3.  Next hop record sub-TLV . . . . . . . . . . . . . . .   6
       2.2.4.  Path count sub-TLV  . . . . . . . . . . . . . . . . .   6
       2.2.5.  Origin Validation sub-TLV . . . . . . . . . . . . . .   7
       2.2.6.  Geo-location sub-TLV  . . . . . . . . . . . . . . . .   7
       2.2.7.  BGP System Load sub-TLV . . . . . . . . . . . . . . .   8
   3.  Operation . . . . . . . . . . . . . . . . . . . . . . . . . .   8
   4.  Deployment considerations . . . . . . . . . . . . . . . . . .   9
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   9
   6.  Security considerations . . . . . . . . . . . . . . . . . . .   9
   7.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  10
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  10
     8.1.  Normative References  . . . . . . . . . . . . . . . . . .  10
     8.2.  Informative References  . . . . . . . . . . . . . . . . .  10
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .  10

1.  Introduction

   Ability to record various information from the mid points given
   control plane packets traverses seems as a useful tool in number of
   control plane protocols in use today.  For some protocols such
   information is critical and mandatory for correct operation while in
   other cases can be used as a set of data for further processing on or
   offline.

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   Recently there have been two proposals discussing need to carry
   opaque to BGP operation data in the two new BGP Attributes proposed
   for such purposes.  As it seems that there can be much more types of
   such data it seems much more efficient to define a single TLV based
   placeholder to carry all optional hop parameters along the path given
   BGP prefix traverses in the network.

   To facilitate such transport this document proposed a definition of
   new BGP Attribute called BGP Path Record Attribute which can be used
   to to carry such new optional information.

   Furthermore the new attribute next to set of predefined types of data
   to be carried can also accommodate local to the particular autonomous
   system set of information to be added at each hop per operator's
   local configuration at given set of BGP speakers in the control plane
   path.

2.  Protocol Extensions

   This document describes a new BGP attribute known as BGP Path Record
   Attribute, along with definition of new TLV and number of sub-TLVs
   which can be used to carry new type of information either defined
   below in this document or already identified in other IETF proposals
   which are included here for illustration purposes only.

   The TLV is defined for both easy extensibility of other then BGP
   speaker related data which may be attached to the advertisements, but
   also due to the fact that such grouped information will be added by
   each capable and participating BGP node as one entity.  The TLVs are
   appended by each participating BGP speaker in the ordered fashion.
   When storing BGP Path Record attribute the TLVs which it contained
   upon reception from peer MUST not be reordered.

   The sub-TLVs on the other hand allow for very easy definition of new
   types of data which may be required to be carried both within this
   document as well as by new subsequent documents.

2.1.  BGP Path Record Attribute

   The BGP Path Record attribute is a new BGP optional transitive
   attribute.  The attribute type code for the Path Record attribute is
   to be assigned by IANA.  The value field of the Path Record attribute
   is defined as a set of one or more Path Record TLVs along with their
   sub-TLVs.

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2.2.  BGP Hop TLV

   A Path Record type 1 TLV called BGP Hop TLV within a Path Record
   Attribute is defined as follows:

   BGP Hop - Type 1 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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |              TYPE             |            LENGTH             |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                    4 OCTET BGP ROUTER ID                      |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                      4 OCTET AS NUMBER                        |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                             FLAGS                             |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       ~                           sub-TLVs                            ~
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                       Figure 1: BGP Hop Type 1 TLV

   TYPE: Two octets encoding the Path Record TLV Type.  Type 1 TLV is
   called BGP Hop TLV and contains information pertaining to BGP speaker
   given prefix has been received at and is advertised further from.

   LENGTH: Two octets encoding the length in octets of the Path Record
   TLV, excluding the type and length fields.  The Length is encoded as
   an unsigned binary integer.

   4 OCTET BGP ROUTER ID: 4 octet BGP router ID assigned to a given BGP
   speaker processing prefix with path containing BGP Path Record
   Attribute.

   4 OCTET AS NUMBER: 4 octet AS number or zero padded 2 octet AS number
   of the autonomous system BGP Hop belongs to.

   FLAGS: Number of boolean flags describing BGP Hop basic
   characteristics.  The following flags are defined for BGP Hop TLV:

   Bit 0:
         NH - Next Hop - Values: 0 - next hop not set; 1 - next hop set
   Bit 1:

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         RR - Route Reflector - Values: 0 - not a route reflector; 1 -
         route reflector
   Bit 2:
         RS - Route Server - Values: 0 - not route server; 1 - route
         server
   Bit 3:
         B - Beacon prefix - Values: 0 - not a special beacon prefix; 1
         - special beacon prefix
   Bits 4-31:
         Reserved for future use

   sub-TLVs: Variable length sub-TLVs describing various information
   pertaining to the TLV they are nested under.  General format of sub-
   TLV is illustrated below:

        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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |              TYPE             |            LENGTH             |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       ~                             VALUE                             ~
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                         Figure 2: sub-TLV format

   TYPE: Two octets encoding of the sub-TLV type used to differentiate
   information types carried in the context of given TLV.

   LENGTH: Two octets encoding the length in octets of the sub-TLV,
   excluding the type and length fields.  The Length is encoded as an
   unsigned binary integer.

   VALUE: Variable length field described in the context of each sub-
   TLV.

   The following optional sub-TLVs are proposed in this document to be
   carried under BGP Hop TLV:

   o  Type 1 - Host Name sub-TLV
   o  Type 2 - Time Stamp sub-TLV
   o  Type 3 - Next Hop record sub-TLV
   o  Type 4 - Path Count sub-TLV
   o  Type 5 - Origin Validation sub-TLV
   o  Type 6 - Geo-location sub-TLV

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   o  Type 7 - BGP System Load sub-TLV

2.2.1.  Host Name sub-TLV

   Type:
         1
   Length:
         Variable (TBD ... if we want to limit the size).
   Value:
         UTF-8 encoded BGP speaker hostname.
   Description:
         Useful for enhance display in number of direct or indirect show
         commands and operational logs.

2.2.2.  Time Stamp sub-TLV

   Type:
         2
   Length:
         10 octets
   Value:
         8 octets - BGP UPDATE message receive timestamp,
         1 octet - flags; Bit 0 - T flag (synchronized to external
         clock) Bits 1-7 - reserved.
         1 octet - Sync type as described in [RFC5905],
   Description:
         For full details of this sub-TLV use case and architecture are
         described in separate document:
         [I-D.litkowski-idr-bgp-timestamp]

2.2.3.  Next hop record sub-TLV

   Type:
         3
   Length:
         4 octets or 16 octets
   Value:
         IPv4 or IPv6 address of the next hop changed by current BGP Hop
   Description:
         For full details of this sub-TLV use case and architecture are
         described in separate document:
         [I-D.zhang-idr-nexthop-path-record]

2.2.4.  Path count sub-TLV

   Type:
         4
   Length:

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         2 octets
   Value:
         Integer indicating number of paths present for a given prefix
         in BGP speaker.
   Description:
         Enables easy visibility in validation of expected propagation
         model for multiple paths of given prefix.  Can validate
         effectiveness of various BGP mechanisms (best-external, bgp
         diverse path, bgp add-paths etc ...) (TBD .. should we include
         how many paths are marked as stale ?)

2.2.5.  Origin Validation sub-TLV

   Type:
         5
   Length:
         10 octets
   Value:
         8 octets - Last time BGP Origin Validation database has been
         updated.
         1 octet - flags; Bit 0 - T flag (synchronized to external
         clock) Bits 1-7 - reserved.
         1 octet - Sync type as described in [RFC5905],
   Description:
         Allows to easily detect issues associated with possible lack of
         synchronization of Origin Validation local database.

2.2.6.  Geo-location sub-TLV

   Type:
         6
   Length:
         16 octets
   Value:
         Proposed encoding follows IETF consensus for representation of
         coordinate based location.

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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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |  LatUnc   |                  Latitude                         +
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       | Lat (cont'd)  |  LongUnc  |               Longitude           +
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |    Longitude (cont'd)         | AType |   AltUnc  |  Altitude +
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |               Altitude (cont'd)               |Ver| Res |Datum|
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                  Figure 3: Geo-location encoding format
   Description:
         Allows to map BGP control plane hops taken by BGP
         advertisements to two or three dimensional geo location
         coordinates of participating BGP speakers.  Encoding details
         are described in [RFC6225] (DHCP geo-location options
         document).

2.2.7.  BGP System Load sub-TLV

   Type:
         7
   Length:
         2 octets
   Value:
         1 octet - avg last 15 min of CPU utilization in percent by BGP
         process/thread
         1 octet - avg last 15 min of BGP process memory use to total
         available memory use in percent
   Description:
         Used as indicator of possible CPU or memory problems of any
         given participating BGP speaker along the BGP control plane
         path.

3.  Operation

   The proposed new BGP Path Record attribute is an opaque entity for
   BGP operation and as such there is no requirement for any direct
   modification to BGP operation or BGP state machine based on the
   information it contains.  It is expected that such feedback loop will
   be performed by operator either by automated or manual process.

   Operator should be able to allow or deny origination of BGP Path
   Record attribute or insertion of any TLV or sub-TLV into BGP UPDATE
   message.  It is however recommended that given BGP implementation

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   adds available sub-TLVs to BGP Hop TLV when particular prefix has
   been received with BGP Path Record Attribute already containing such
   sub-TLVs.

   BGP policy should be enhanced to allow for easy filtering of BGP Path
   Record attribute both on egress as well as ingress eBGP sessions.

   BGP Path Record attribute can be used within any AFI/SAFI.

4.  Deployment considerations

   It needs to be recognized that some sub-TLVs of BGP Hop TLV of BGP
   Path Record attribute can break update packing.  Therefor it is
   strongly recommended that sub-TLVs type 2, 4, 7 as defined above are
   to be used only for specific beacon prefixes injected into BGP
   control plane by operator and flagged with the "B" bit within the
   originating BGP Hop TLV.

   Beacon prefixes due to the store-and-forward nature of P2MP BGP
   distribution for information correctness should be carefully injected
   and withdrawn from entire network before subsequent injection is to
   take place again.

5.  IANA Considerations

   This document defines a new BGP attribute known as a BGP Path Record
   Attribute.  The code point for a new BGP Path Record attribute has to
   be assigned by IANA from the BGP Path Attributes registry.

   This document requests IANA to define and maintain a new registry
   named: "BGP Path Record Attribute TLV types".  The reserved pool of
   0x0000-0xFFFF has been defined for its allocations.  The allocations
   policy is on a first come first served basis.  The recommended
   allocation of 0x0001 is to be allocated for BGP Hop TLV.

   This document requests IANA to define and maintain a new registry
   named: "BGP Hop sub-TLV types".  The reserved pool of 0x0000-0xFFFF
   has been defined for its allocations.  The allocations policy is on a
   first come first served basis.  The recommended allocation of first 7
   sub-TLVs are indicated in section 2.2 titled: BGP Hop TLV.

6.  Security considerations

   No new security issues are introduced to the BGP protocol by this
   specification.

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7.  Acknowledgements

   Authors would like to acknowledge ... for their valuable input,
   review and comments.

8.  References

8.1.  Normative References

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

   [RFC4223]  Savola, P., "Reclassification of RFC 1863 to Historic",
              RFC 4223, October 2005.

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

8.2.  Informative References

   [I-D.litkowski-idr-bgp-timestamp]
              Litkowski, S., Patel, K., and J. Haas, "Timestamp support
              for BGP paths", draft-litkowski-idr-bgp-timestamp-00 (work
              in progress), July 2014.

   [I-D.zhang-idr-nexthop-path-record]
              Li, Z., Zhang, L., and S. Hares, "NEXTHOP_PATH_RECORD
              ATTIBUTE for BGP", draft-zhang-idr-nexthop-path-record-00
              (work in progress), July 2014.

   [RFC5905]  Mills, D., Martin, J., Burbank, J., and W. Kasch, "Network
              Time Protocol Version 4: Protocol and Algorithms
              Specification", RFC 5905, June 2010.

   [RFC6225]  Polk, J., Linsner, M., Thomson, M., and B. Aboba, "Dynamic
              Host Configuration Protocol Options for Coordinate-Based
              Location Configuration Information", RFC 6225, July 2011.

Author's Address

   Robert Raszuk
   Individual

   Email: robert@raszuk.net

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