IDR Working Group                                               S. Hares
Internet-Draft                                   Hickory Hill Consulting
Intended status: Standards Track                        15 November 2024
Expires: 19 May 2025


           BGP Flow Specification Version 2 - More IP Filters
                draft-hares-idr-fsv2-more-ip-filters-04

Abstract

   The BGP flow specification version 2 (FSv2) for Basic IP defines user
   ordering of filters along with FSv1 IP Filters and FSv1 actions.
   This draft defines the format for the Extended IP Filters for Flow
   Specification FSv2.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

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   This Internet-Draft will expire on 19 May 2025.

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   provided without warranty as described in the Revised BSD License.





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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  FSv2 background . . . . . . . . . . . . . . . . . . . . .   3
     1.2.  Definitions and Acronyms  . . . . . . . . . . . . . . . .   5
     1.3.  RFC 2119 language . . . . . . . . . . . . . . . . . . . .   6
   2.  Extending the IP Filters  . . . . . . . . . . . . . . . . . .   6
     2.1.  Dependency Filter Chain in FSv2 NLRI Header . . . . . . .   6
     2.2.  Extended IP Filters TLV . . . . . . . . . . . . . . . . .   8
     2.3.  Extended IP Filters Component Groups  . . . . . . . . . .  10
     2.4.  Ordering within FSv2 NLRI in Update Packet  . . . . . . .  12
     2.5.  Template for Extended IP Components . . . . . . . . . . .  13
   3.  New Extended IP Components  . . . . . . . . . . . . . . . . .  14
     3.1.  TTL (type = 0(0x00) or 14(0x0E))  . . . . . . . . . . . .  14
   4.  Validation and Error Handling . . . . . . . . . . . . . . . .  15
   5.  Manageability . . . . . . . . . . . . . . . . . . . . . . . .  17
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  17
     6.1.  FSv2 Component types  . . . . . . . . . . . . . . . . . .  17
     6.2.  FSV2 IP Extended Filter Groups  . . . . . . . . . . . . .  18
       6.2.1.  Template for Requesting FSv2 Extended Filters
               Group . . . . . . . . . . . . . . . . . . . . . . . .  18
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .  19
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  19
     8.1.  Normative References  . . . . . . . . . . . . . . . . . .  19
     8.2.  Informative References  . . . . . . . . . . . . . . . . .  22
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .  23

1.  Introduction

   Version 2 of BGP flow specification (FSv2) has a series of
   foundational documents ([I-D.ietf-idr-fsv2-ip-basic], this document,
   [I-D.hares-idr-fsv2-more-ip-actions], and [draft-hares-idr-fsv2-non-
   ip]) plus drafts on specific filter components, actions, or groups of
   filter components and actions.

   The remainder of this introductory section provides a introduction to
   FSv2.

   Section 2 contains a description of the format of the FSv2 NLRI with
   the Extended IP Filters TLV.  The Extended IP Filters TLV allows the
   user to specify new IP Filters components and a group of IP Filter
   components.  The concept of a group of filter components allows an
   BGP peer originating a FSv2 NLRI with the Extended IP Filter TLV to
   pass what components the originating BGP Peer expects will be
   supported by the BGP Peers receiving the FSv2 Extended Filter TLV.
   The group field is designed to aid upgrades to additional component
   by providing a simple check the FSv2 component range passed in the
   Extended Filters TLV.  Groups can be register with IANA in either a



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   FCFS range or IETF Consensus range.  Section 2 also provides
   templates for defining: a) new components to be passed in the
   Extended IP Filter group and b) new Extended IP Filter groups.

   Section 3 provides two new Filters approved in IDR WG drafts.
   Section 3.1 provides definitions for new components: TTL, SID in IPv6
   Segment Routing header (SRH).  These two components were defined in
   the original specification for Flow Specification v2
   ([I-D.ietf-idr-flowspec-v2]).  Section 3.2 also provides prototypes
   for a few existing components to aid authors of IDR drafts (current
   or proposed) examples to aid their quick use of the Extended IP
   Filters.

   Section 4 provides information on Validation and Error handling for
   the Extended Filters TLV.  Section 5 contains manageability
   considerations for FSv2 with Extended IP Filters TLV.  Section 6
   contains IANA considerations and section 7 contains security
   considerations.

1.1.  FSv2 background

   FSv2 specifies new user-ordered filters that will be used with the
   IPv4 (AFI=1) and IPv6 (AFI=2) 2 new SAFIs (TBD1, TBD2) for FSv2 to be
   used with 5 AFIs (1, 2, 6, 25, and 31) to allow user-ordered lists of
   traffic match filters for user-ordered traffic match actions encoded
   in Communities (Extended or Wide Communities).  The first SAFI (TBD1)
   is used for IP forwarding, and the second SAFI (TBD2) will be used
   with VPNs.  The supported AFI/SAFI combinations in FSV2 are:

   *  IPV4 (AFI=1, SAFI=TBD1),

   *  IPv6 (AFI=2, SAFI=TBD1),

   *  L2 (AFI=6, SAFI=TBD1),

   *  SFC (AFI=31, SAFI=TBD1),

   *  BGP/MPLS IPv4 VPN (AFI=1, SAFI=TBD2),

   *  BGP/MPLS IPV6 VPN (AFI=2, SAFI=TBD2),

   *  BGP/MPLS L2VPN (AFI=25, SAFI=TBD2), and

   *  SFC VPN (AFI=31, SAFI=TBD2)

   FSv1 and FSv2 use different AFI/SAFIs to send flow specification
   filters.  Since BGP route selection is performed per AFI/SAFI, this
   approach can be termed “ships in the night” based on AFI/SAFI.



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   The full FSv2 specification ( Version 2 of BGP flow specification
   (FSv2) was original defined in [I-D.ietf-idr-flowspec-v2].  contains
   more than initial implementers desired to put in a single upgrade.
   Therefore, the original FSv2 draft remains an WG draft, but the
   content will be split out into groups of functions that can be easily
   deployed as upgrades to FSv1.  The upgrades will come in the
   following groups:

   FSv2 IP Basic ([I-D.ietf-idr-fsv2-ip-basic]):  This specification
      defines the FSv2 NLRI that allows user ordering of filters plus in
      a IP Basic TLV which only allows FSv1 components.  FSv2 actions
      are implemented in Extended Communities (FSv2-EC).  FSv2 defines
      how the actions defined in FSv2-EC are ordered.  Multiple FSv2-EC
      actions can be attached to a single filter component, so FSv2
      defines an Action Chain Ordering community to define what happens
      if one of these multiple actions fails.  All FSv2 implementations
      must support the minimal subset in this document.

   FSv2 IP Extended Filters (this document):  This document defines the
      Extended IP Filters TLV to allow easy addition of FSv2 filters.
      The original FSv2 had definitions [I-D.ietf-idr-flowspec-v2] for
      FSv2 TTL and SRv6 Header (SRH) filter so these components are
      included in this specification.

   FSv2 Individual drafts for IP Extended Filters:  These drafts should
      utilize the template given in section 2.2 Current proposals for
      Extended IP Filters can request component identifier(s) be
      included in this draft's BGP FSv2 Component registry list.
      Grouping of Extended IP Filter can be registered in the Extended
      IP Filter Groups (see section 2.3).

   FSv2 IP Extended Actions ([I-D.hares-idr-fsv2-more-ip-actions]):
      This document defines a FSV2 TLV for the for the BGP Community
      Path Attribute, and a protocols for combining FSv2 Extended
      Community (FSv2-EC) Actions with FSv2 Community Path Attributes.

   FSv2 Individual drafts for FSv2 Actions:  These drafts may define
      FSv2 actions in Extended Communities and/or FSv2 actions in the
      FSv2 TLV of the BGP Community Attribute.

   Non-IP Filters (draft-hares-idr-fsv2-non-ip]:  defines the template
      for FSv2 non-IP filters for MPLS, L2 traffic, SFC, and tunnel
      traffic, and FSV2 non-IP actions.

   Individual drafts on Non-IP Filters:  IDR drafts for non-ip functions
      passed in BGP FSv2 includes: MPLS ([draft-hares-idr-fsv2-mpls]),
      L2VPN ([I-D.ietf-idr-flowspec-l2vpn]), and NV03
      ([I-D.ietf-idr-flowspec-nvo3]).



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1.2.  Definitions and Acronyms

   AFI:  Address Family Identifier

   AS:  Autonomous System

   BGPSEC:  secure BGP [RFC8205] updated by [RFC8206]

   BGP Session ephemeral state:  state which does not survive the loss
      of BGP peer session.

   BGP Configuration state:  state which persist across a reboot of
      software module within a routing system or a reboot of a hardware
      routing device.

   DDOs:  Distributed Denial of Service.

   Ephemeral state:  state which does not survive the reboot of a
      software module, or a hardware reboot.  Ephemeral state can be
      ephemeral configuration state or operational state.

   FS:  Flow Specification.

   FSv1:  Flow Specification version 1 [RFC8955] [RFC8956]

   FSv2:  Flow Specification version 2 [I-D.ietf-idr-fsv2-ip-basic],
      [this document].

   FS-EC:  Flow Specification Extended Community

   FSv1-EC:  FSv1 Extended Community that signals actions that occur
      after a filter match

   FSv2-EC:  FSv2 Extended Community that signals actions that occur
      after a filter match.  FSv2-EC are preformed with either a default
      order of processing or signal the FSv2-EC are performed in
      implementation order.

   NETCONF:  The Network Configuration Protocol [RFC6241].

   RESTCONF:  The RESTCONF configuration Protocol [RFC8040].

   RIB:  Routing Information Base.

   ROA:  Route Origin Authentication [RFC9582]

   RR:  Route Reflector.




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   SAFI:  Subsequent Address Family Identifier.

1.3.  RFC 2119 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 BCP 14 [RFC2119]
   [RFC8174] when, and only when, they appear in all capitals as shown
   here.

2.  Extending the IP Filters

   The format of the FSv2 NLRI field for IP Filters is defined in
   [I-D.ietf-idr-fsv2-ip-basic].  This format includes a common header
   with fields for user specified order, dependency filter chain, and a
   TLV for filter components (type, length, value).

   This section defines the use of the dependency filter chain (section
   2.1) in the NLRI and the format of the Extended IP Filters TLV
   (section 2.2).  The Extended IP Filter group provides a flexible
   means to define which components are supported by the Extended IP
   Filter TLV.  Four Extended Filter Component groups are defined in
   section 2.3, but additional may be defined via an IANA Registry.  The
   ordering of Filters is by user define order number, then component,
   then value within a component.  Section 2.4 provides the rules for
   ordering for FSv2 NLRI with IP Basic Filters and Extended IP Filters.
   Section 2.5 provides a template for new Extended IP Components.

2.1.  Dependency Filter Chain in FSv2 NLRI Header

   FSv2 filters may be distributed in multiple BGP UPDATE packets.  The
   format of the FSv2 NLRI is shown in Figure 3-1.  In FSv2, the user
   can define the order of the filters by an including an order in the
   FSV2 NLRI prior to the filter.  FSv2 also defines an optional
   dependency filter chain to allow the filter chains to be identified
   across all FSV2 Filter chains.  This information may be installed
   from BGP data based into firewalls.














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    +-------------------------------+
    | NLRI length (2 octets)        |
    +-------------------------------+
    |    TLVs+                      |
    | +===========================+ |
    | | order (4 octets)          | |
    | +---------------------------+ |
    | | Dependent filter chain    | |
    | |(type, chain ID, count,    | |
    | | item) (8 octets)          | |
    | +---------------------------+ |
    | + FSv2 Filter type          + |
    | | (2 octets)                | |
    | +---------------------------+ |
    | + length TLVs (2 octet)     + |
    | + --------------------------+ |
    | + value (variable)          + |
    | +---------------------------+ |
    +-------------------------------+

     Figure 2-1 - FSv2 NLRI with Extended IP Filter type.

   Where:

   order:  4 octet field for the FSv21 user defined order of the filter
      with a a value of 1-n.  The value of zero is invalid

   Dependent Filters Chain:  8 octets for identifying a chain of FSv2
      filters that must be deployed at the same time.  (See figure 2-2
      for details.)  If the dependency filters chain field is also zero,
      there is no dependency filter chain defined.

   FSv2 Filter type:  2 octet field for the FSv2 filter type.  The
      Extended IP Filter type value is 2.

   length:  2 octet field for the length of the value field.

   value field:  variable length field defined per FSv2 filter type.
      The value field for the Extended IP Filter rules has the format
      shown in Figure 2-3.

   The dependency filter chain has the following components:









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       +-------------------------------+
       |  Version  (1 octet)           |
       +-------------------------------+
       |  chain id (3 octets)          |
       +-------------------------------+
       |  Count of items (2 octets)    |
       + ------------------------------+
       |  Item (2 octets)              |
       +-------------------------------+

     Figure 2-2 – IP header SubTLV format

   where:

   Version:  This 1 octet field defines the version of the filter chain.
      Valid values are 1-0xFF.  Value 0 is reserved.

   Chain ID:  This 3 octet field identifies the filter chain.  Valid
      values include 0x00001 to 0xFFFFFF with the value zero (0x000000)
      being reserved.

   Count of items:  This 2 octet field contains the count of item on
      this filter dependency chains.  Valid values are 0x0001 to 0xFFFF
      with the value of zero being reserved.

   Item:  This (2 octets): filter sequence number on chain Valid values
      are 0x0001 to 0xFFFF with the value of zero being reserved.

2.2.  Extended IP Filters TLV

   The Extended IP Filters TLV has a type value of 2 with a variable
   length.  The Extended IP Filters value field has the form shown in
   Figure 2-3 where:

   FSv2 Extended Filters Group:  is a 2 octet field indicating the group
      of components supported.  Three groups are defined in this
      document.  Additional groups may be defined by registering the
      group in the FSv2 Extended IP Filter group registry (see IANA
      registry policy in section 6.2), but those groups are outside the
      scope of this document.

   Components+:  This field is a sequence of FSv2 Components with the
      format shown in figure 2-4.








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       Extended Filters value field
    +-------------------------------+
    |  +--------------------------+ |
    |  | FSv2 Extended Filters    | |
    |  | group (2 octets)         | |
    |  +--------------------------+ |
    |  |  Components+ (variable)  | |
    |  +--------------------------+ |
    +-------------------------------+

    Figure 2-3 - Extended IP Filters TLV

   Each Component is a sequence of TLVs with the format

     +-------------------------------+
     |  Component Type (1 octet)     |
     +-------------------------------+
     |  Component length (2 octets)  |
     + ------------------------------+
     |  Component value (variable)   |
     +-------------------------------+

     Figure 2-4 – Component format

   Where:

   Component type:  is a 1 octet specify the component type.

   Component length:  is a 2 octet value specifying the component
      length.

   Component value:  is a variable field defined per component.

   The valid components for the Extended IP Filters defined by this
   specification are listed in table 2-X below.  These components
   include the following:

   IP Basic components:  Components 1-13 are defined in
      [I-D.ietf-idr-fsv2-ip-basic].

   TTL  Filter on Time to Live in IPv4 packet or maximum hop limit in
      IPv6 packets.

   SID function  SID in segment routing header (SRH) in the IPv6 packet
      (per [I-D.ietf-idr-flowspec-srv6])

   NRP ID  NRP ID in Next Hop header in IPv6 packet (per
      [I-D.ietf-idr-flowspec-network-slice-ts]



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              Table 2-1

    Components for Extended IP Filters

   SubTLV    Extended IP Filters Components
   -type     for IP Extended Filters version 2
   --------  ----------------------------------
      0 -    TTL
      1 -    IP Destination prefix
      2 -    IP Source prefix
      3 –    IPv4 Protocol od
             IPv6 Upper Layer Protocol
      4 –    Port
      5 –    Destination Port
      6 –    Source Port
      7 –    ICMPv4 type or ICMPv6 type
      8 –    ICMPv4 code or ICMPv6 code
      9 –    TCP Flags
     10 –    Packet length
     11 –    DSCP
     12 –    Fragment
     13 –    Flow Label
     14 -    TTL
     15 -    Reserved
     16 -    SID in Routing IPv6 Header
     17 -    NRP ID in IPv6 Header

2.3.  Extended IP Filters Component Groups

   Three groups are defined for Extended IP Filters:

   FSv1:  comprised of FSv2 components 1-13 (see Table 3-1)

   FSv1 with TTL  compromised of FSv2 components 0-14 where TTL has
      component values 0 and 14 (see Table 3-2).

   SR (Segment Routing)  comprised of FSv2 components 0-17 were TTL has
      the component value of 0 and 14 (see Table 3-3).













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   Table 2-2 FSv1 Component Group (0x00)

   SubTLV    Extended IP Filters Components
   -type     for IP Extended Filters version 1
   --------  ----------------------------------
      1 -    IP Destination prefix
      2 -    IP Source prefix
      3 –    IPv4 Protocol or
             IPv6 Upper Layer Protocol
      4 –    Port
      5 –    Destination Port
      6 –    Source Port
      7 –    ICMPv4 type or ICMPv6 type
      8 –    ICMPv4 code or ICMPv6 code
      9 –    TCP Flags
     10 –    Packet length
     11 –    DSCP
     12 –    Fragment
     13 –    Flow Label


   Table 2-3 FSv1 + TTL Component Group (0x01)

   SubTLV    Extended IP Filters Components
   -type     for IP Extended Filters version 1
   --------  ----------------------------------
      0 -    TTL
      1 -    IP Destination prefix
      2 -    IP Source prefix
      3 –    IPv4 Protocol or
             IPv6 Upper Layer Protocol
      4 –    Port
      5 –    Destination Port
      6 –    Source Port
      7 –    ICMPv4 type or ICMPv6 type
      8 –    ICMPv4 code or ICMPv6 code
      9 –    TCP Flags
     10 –    Packet length
     11 –    DSCP
     12 –    Fragment
     13 –    Flow Label
     14 -    TTL









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    Table 2-4 Segment Routing Group (0x02)

   SubTLV    Extended IP Filters Components
   -type     for IP Extended Filters version 2
   --------  ----------------------------------
      0 -    TTL
      1 -    IP Destination prefix
      2 -    IP Source prefix
      3 –    IPv4 Protocol od
             IPv6 Upper Layer Protocol
      4 –    Port
      5 –    Destination Port
      6 –    Source Port
      7 –    ICMPv4 type or ICMPv6 type
      8 –    ICMPv4 code or ICMPv6 code
      9 –    TCP Flags
     10 –    Packet length
     11 –    DSCP
     12 –    Fragment
     13 –    Flow Label
     14 -    TTL
     15 -    Reserved
     16 -    SID in Routing IPv6 Header
     17 -    NRP ID in Next Hop HEader

   Table 2-5 Extended IP Component Ranges

   Sub-TLV range   Definition
   -------------  -------------
      1-13        V1 filters
     14-63        IP Extended Filters

2.4.  Ordering within FSv2 NLRI in Update Packet

   The transmission of TLVs within a FSV2 NLRI SHOULD be sent via
   ascending user order.

   Within a single user order, the TLVs should be ordered by FSv2 Filter
   type.  The FSv2 Filter types which MUST be supported for the Extended
   IP Filter support are Filter Type IP Basic (type = 1) and Filter Type
   Extended IP Filters (type = 2).  Other FSv2 Filter types MAY be
   supported, but the support of those filter types is outside the scope
   of this document.

   Within a single user order number and the same IP Basic Filter Type,
   the components should be ordered by ascending numerical order of the
   component type.




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   Within a single user order number and the same Extended IP Basic
   Type, the components should also be ordered by ascending component
   numbers.  The Extended IP Filters version number simply indicates
   which components are required to be supported per version.

   Within a single user order and a single component number, the order
   of the filters is defined by the component.  For example, if the
   component types are the same, then the value fields are compared as
   defined in [I-D.ietf-idr-fsv2-ip-basic], [RFC8955] and [RFC8956].
   The filters MUST be stored with the value fields in ascending order.
   NLRIs having TLVs which do not follow the above ordering rules MUST
   be considered as malformed by a BGP FSv2 propagator.  This rule
   prevents any ambiguities that arise from the multiple copies of the
   same NLRI from multiple BGP FSv2 propagators.  A BGP implementation
   SHOULD treat such malformed NLRIs as ""Treat-as-withdraw"" [RFC7606].

2.5.  Template for Extended IP Components

   Summary:  One line title summary

   Component type:  The numerical value for component type.  If the
      component value has not been assigned by IANA, this value should
      be in the form TBDx where x is a number (1..N).

   Description:  Description of what component does.

   What field component targets in IPv4 packet:  The specific field or
      fields the compnent filters.  If the field filter is in the IPv6
      packet, then this field is left (n/a).

   What field Filter targets in IPv6 packet:  The specific field or
      fields the compnent filters.  If the field filter is in the IPv4
      packet, then this field is left (n/a).

   Length:  Describe the length or possible lengths of this field.

   Encoding of Component Value field  This is the encoding of the value
      in FSv2 NLRI.  The best descriptions combine a diagram plus a
      description.

   Ordering within component:  The mechanism to order if multiple
      components of the same type occur.

   conflicts with other filters:  Describe what other filters this
      component could interfere with.

   Example encoding:  Provide one simple example of the encoding of a
      filter for the component.



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   references:  earlier documents which defined this filter.

3.  New Extended IP Components

3.1.  TTL (type = 0(0x00) or 14(0x0E))

   Summary:  Defines matches for 8-bit (1 octet) TTL field in IPv4
      header and 8-bit (1 octet) in IPv6 header Hop limit.

   Component Type:  0 (0x00) and 14 (0x0E).  Component type of zero
      (0x00) places the TTL (IPv4) or Hop limit (IPv6) filter prior to
      any other component test.  Component ID value of 14 (0x0E) places
      the TTL (IPv4)/Hop limit (IPv6) filter after all IP Basic Filters.

   Description:  This component filters IPv4 packets on a certain range
      of values for TTL for IPv4 packets or a range of avalues for Hop
      Limit for IPv6 packets.

   What field Filter targets in IPv4 packet:  TTL field

   What field Filter targets in IPv6 packet:  Hop Limit field

   Length:  variable with valid values 2-N in increments of 2 octets.

   Encoding of Component:


   TTL Component Value encoding

   <[numeric_op, value]+>

      Figure 3-1

   where:

   numeric_op:  1 octet field can express less than, greater than, or
      equal.  The field numeric_op is defined in
      [I-D.ietf-idr-fsv2-ip-basic].  This is the same format as the
      numeric-op for FSv1 components.

   value:  is a 1 octet value for TTL for IPv4 packets and Hop limit for
      IPv6.

   ordering of components:  by full value of number_op concatenated with
      value

   conflict:  none




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   reference:  draft-bergeon-flowspec-ttl-match-00.txt

4.  Validation and Error Handling

   Validation of the FSv2 NLRI follows the rules from section 4.1 of
   [I-D.ietf-idr-fsv2-ip-basic].  For ease of reference to this
   validation procedure, the implementer might consider the following
   facts:

   Extended IP filters -  are passed as either IPv4 (AFI=1, SAFI=TBD1),
      IPv6 (AFI=2, SAFI=TBD1), IPv4 VPN (AFI=1, SAFI=TBD2), IPv6 VPN
      (AFI=2, SAFI=TBD2).  or (AFI=2) SAFI=TBD1 or SAFI=TBD2.

   IP Extended filters sent in SAFI=TBD1 -  are validated against
      SAFI=1.  To be specific, (AFI=1, SAFI=TBD1) is validated against
      (AFI=1, SAFI=1), and (AFI=2, SAFI=TBD1) is validasted against
      (AFI=2, SAFI=1).

   IP Extended filters sent in SAFI=TBD2 -  are validated against
      SAFI=128.  To be specific, (AFI=1, SAFI=TBD2) is validated against
      (AFI=1, SAFI=128) AND (AFI=2, SAFI=TBD2) is validated against
      (AFI=2, SAFI=128).

   Validation of the FSv2 NLRI follows the rules from section 4.2 of
   [I-D.ietf-idr-fsv2-ip-basic] apply to the FSV2 NLRI filters.  For
   ease of reference to this section, implementers might consider the
   following facts:

   FSv2 defines a Rule-0 for 0/0 with "permit-all" action. -  By
      default, FSv2 (and FSv1) restrict the flow from permit all.  By
      configuration, Rule-0 could be set to 0/0 with "permit-none" and
      filters could have the benefit of allowing traffic.  If this
      configuration knob is set, then it MUST be used in a limited
      Domain of cooperating networks.

   FSv2 rules are ordered by ascending user order number, FSv2 Filter
   type, FSv2 component type, and FSv2 component value.  This ordering
      rules means that multiple FSv2 filter rules with the same user
      order number of ordered by ascending FSv2 filter types (IP Basic
      (0x01) and Extended IP Filters (0x02)).  If the FSv2 filter has
      the same user order and Filter type, then the order is by
      ascending FSv2 component type numbers.  Finally, if FSv2 filters
      have the same user order, Flter type, component type, then the
      filter is ordered by the component value.

   Order is deterministic, but arbitrary.  Users may use the user
      ordering and dependency chain to establish more complex
      relationships.



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   The following two error handling rules stated in Section 4.1.3 of
   [I-D.ietf-idr-fsv2-ip-basic] must be followed by all BGP speakers:

   1) FSv2 NLRI having TLV which do not have the correct length or
   syntax  must be considered MALFORMED.  Syntax is defined as having
      each field within NLRI header (order, dependent filters chain and
      within the FSv2 TLV (IP Basic TLV or Extended TLV) header, and
      each component.  Any MALFORMED FSv2 NLRI is handled as "TREAT AS
      WITHDRAW" per [RFC7606].

   2) Any FSV2 NLRI which do not follow the ordering rules  described in
      section 4 [I-D.ietf-idr-fsv2-ip-basic] for filters is considered
      MALFORMED.

   Actions are transmitted on Extended Communities (EC) for FSv2 basic
   actions (FSv2-EC) or BGP Community path attribute (CPA) with FSv2 TLV
   (FSv2-CPA).  The following rules MUST be followed by the FSv2
   actions:

   If BGP Community Path Attribute is not supported, then:  FSv2-EC MUST
      be ordered by FSv2 default order (see
      [I-D.ietf-idr-fsv2-ip-basic]) if one of the two conditions is not
      present:

      *  Implement configuration knob that implementation specific order
         is set

      *  Action Chain Order (ACO) FSV2-EC is attached with the Action
         dependency set to implementation specific

   If a BGP Community Path Attribute with a FSv2 TLV (FSv2-CPA)is
   supported and attached in an invalid form, then:  the FSv2-CPA is
      ignored and not forwarded.

   If BGP Community Path Attribute with a FSv2 TLV (FSv2-CPA) is
   supported and a valid FSv2-CPA is attached, then:  the FSv2-CPA takes
      precedence over FSv2-EC.  The BGP Community Path attribute allows
      for user ordering with user order values of [1-N].  By default,
      the FSv2-EC follow the FSv2-CP actions (N+1) with all FSv2-EC on
      the same user order number.  Early deployments of FSv2-CPA may
      want to reverse this order (first FSv2-EC, then BGP Community Path
      attribute).  If so, FSv2-EC should be defined as [action order 0]
      by configuration knob.








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5.  Manageability

   FSv1 is a key part of many existing networks.  The introduction of
   FSv2 is expected to be a phased process. where FSv1 is replaced
   slowly.  One potential way this might occur is the following:

   FSv2 IP basic replaces FSv1 -  A FSv2 implementation may simply
      configure FSv2 with the same IP Basic components as used in FSv1,
      and a user order of 1 for FSv2.  FSv1 would be configured with a
      default user order of 10.  The same Extended Communities are
      passed plus an ACO community (Generic Transitive Extended
      Community (0x01)) with ACO-Dependency of 0x0 (implementation
      specific) and AC-FAilure (0x00).

   FSv2 IP basic with default Action order  ACO FSv2-EC used when
      FSv2-EC action order is needed to detect conflicts in actions in
      remote BGP peers.

   FSv2 IP basic with flexible user order  After the implementations are
      solid, it is expected that networks will use FSv2 user ordering to
      provide flexible ordering.

   FSv2 Extended IP Filters with no dependency chain are deployed.  The 
      dependency chain field can be left as zero for any deployment of
      FSv2 Filter NLRI.

   FSv2 MPLS Filters with no dependency chain are deployed.  The default
      ordering of the filters with the same user order number would be
      IP Basic Filters (0x01), Extended IP Filters (0x02), and MPLS
      Filters (0x03).  If MPLS filters need to be done first, then the
      user order of MPLS would need to be lower than Extended IP
      filters.  Please note that SRv6 headers are Extended IP Filters so
      SRv6 takes precedence over MPLS label filters.

6.  IANA Considerations

   This section complies with [RFC7153].

6.1.  FSv2 Component types

   IANA is requested to indicate [this draft] as a reference on the
   following assignments in the Flow Specification Component Types
   Registry:








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    ID    Name         Reference
    ----  -----------  -----------------
     0    TTL          [this document]
    14    TTL          [this document]
    15    Reserved     [this document]
    16    Partial SID  [this document]
    17    NRP ID       [this document]

6.2.  FSV2 IP Extended Filter Groups

   IANA is requested to create the following a registry for extended IP
   Filters Group with the following values.  Registry type is "IETF-
   Consensus" for values 0x04 to 0xFF.  Registry type is "FCFS" for
   values 0x100 to 0x1FF.


    ID   Group Name    Valid FSV2
                       component values   Reference
    ---  -----------   ----------------  -----------------
     0   FSv1          0-13              [this document]
     1   FSv1 + TTL    0-14              [this document]
     2   SRv6          0-17              [this document]

     Values 0x04  - 0xFF (255) - Assigned via IETF Consensus
     Values 0x100 - 0x1FF (300-511) - Expert review
     Values 0x200 - 0x2FF (512-7670 - FCFS

   A template for requesting the IP Filters group assignment is given
   below.

6.2.1.  Template for Requesting FSv2 Extended Filters Group

   Name:  Provide a short name (10 characters, maximum)

   Summary:  One line title summary

   Component IDs included:  The numerical value for component ID type.

   Type of Group Assignment:  This should either be IETF Consensus,
      Expert review or FCFS.

   Document reference:  document that defines group

   Contact:  Person making request







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7.  Security Considerations

   The use of ROA improves on [RFC8955] by checking to see of the route
   origination.  This check can improve the validation sequence for a
   multiple-AS environment.

   >The use of BGPSEC [RFC8205] to secure the packet can increase
   security of BGP flow specification information sent in the packet.

   The use of the reduced validation within an AS [RFC9117] can provide
   adequate validation for distribution of flow specification within a
   single autonomous system for prevention of DDoS.

   Distribution of flow filters may provide insight into traffic being
   sent within an AS, but this information should be composite
   information that does not reveal the traffic patterns of individuals.

8.  References

8.1.  Normative References

   [I-D.ietf-idr-flowspec-l2vpn]
              Weiguo, H., Eastlake, D. E., Litkowski, S., and S. Zhuang,
              "BGP Dissemination of L2 Flow Specification Rules", Work
              in Progress, Internet-Draft, draft-ietf-idr-flowspec-
              l2vpn-24, 6 October 2024,
              <https://datatracker.ietf.org/doc/html/draft-ietf-idr-
              flowspec-l2vpn-24>.

   [I-D.ietf-idr-flowspec-network-slice-ts]
              Dong, J., Chen, R., Wang, S., and J. Wenying, "BGP
              Flowspec for IETF Network Slice Traffic Steering", Work in
              Progress, Internet-Draft, draft-ietf-idr-flowspec-network-
              slice-ts-03, 20 October 2024,
              <https://datatracker.ietf.org/doc/html/draft-ietf-idr-
              flowspec-network-slice-ts-03>.

   [I-D.ietf-idr-flowspec-nvo3]
              Eastlake, D. E., Weiguo, H., Zhuang, S., Li, Z., and R.
              Gu, "BGP Dissemination of Flow Specification Rules for
              Tunneled Traffic", Work in Progress, Internet-Draft,
              draft-ietf-idr-flowspec-nvo3-20, 16 June 2024,
              <https://datatracker.ietf.org/doc/html/draft-ietf-idr-
              flowspec-nvo3-20>.

   [I-D.ietf-idr-flowspec-srv6]
              Li, Z., Chen, H., Loibl, C., Mishra, G. S., Fan, Y., Zhu,
              Y., Liu, L., Liu, X., and S. Zhuang, "BGP Flow



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              Specification for SRv6", Work in Progress, Internet-Draft,
              draft-ietf-idr-flowspec-srv6-06, 16 October 2024,
              <https://datatracker.ietf.org/doc/html/draft-ietf-idr-
              flowspec-srv6-06>.

   [I-D.ietf-idr-fsv2-ip-basic]
              Hares, S., Eastlake, D. E., Dong, J., Yadlapalli, C., and
              S. Maduschke, "BGP Flow Specification Version 2 - for
              Basic IP", Work in Progress, Internet-Draft, draft-ietf-
              idr-fsv2-ip-basic-02, 14 October 2024,
              <https://datatracker.ietf.org/doc/html/draft-ietf-idr-
              fsv2-ip-basic-02>.

   [RFC0791]  Postel, J., "Internet Protocol", STD 5, RFC 791,
              DOI 10.17487/RFC0791, September 1981,
              <https://www.rfc-editor.org/info/rfc791>.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

   [RFC4271]  Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A
              Border Gateway Protocol 4 (BGP-4)", RFC 4271,
              DOI 10.17487/RFC4271, January 2006,
              <https://www.rfc-editor.org/info/rfc4271>.

   [RFC4360]  Sangli, S., Tappan, D., and Y. Rekhter, "BGP Extended
              Communities Attribute", RFC 4360, DOI 10.17487/RFC4360,
              February 2006, <https://www.rfc-editor.org/info/rfc4360>.

   [RFC4760]  Bates, T., Chandra, R., Katz, D., and Y. Rekhter,
              "Multiprotocol Extensions for BGP-4", RFC 4760,
              DOI 10.17487/RFC4760, January 2007,
              <https://www.rfc-editor.org/info/rfc4760>.

   [RFC5065]  Traina, P., McPherson, D., and J. Scudder, "Autonomous
              System Confederations for BGP", RFC 5065,
              DOI 10.17487/RFC5065, August 2007,
              <https://www.rfc-editor.org/info/rfc5065>.

   [RFC5701]  Rekhter, Y., "IPv6 Address Specific BGP Extended Community
              Attribute", RFC 5701, DOI 10.17487/RFC5701, November 2009,
              <https://www.rfc-editor.org/info/rfc5701>.







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   [RFC6482]  Lepinski, M., Kent, S., and D. Kong, "A Profile for Route
              Origin Authorizations (ROAs)", RFC 6482,
              DOI 10.17487/RFC6482, February 2012,
              <https://www.rfc-editor.org/info/rfc6482>.

   [RFC7153]  Rosen, E. and Y. Rekhter, "IANA Registries for BGP
              Extended Communities", RFC 7153, DOI 10.17487/RFC7153,
              March 2014, <https://www.rfc-editor.org/info/rfc7153>.

   [RFC7606]  Chen, E., Ed., Scudder, J., Ed., Mohapatra, P., and K.
              Patel, "Revised Error Handling for BGP UPDATE Messages",
              RFC 7606, DOI 10.17487/RFC7606, August 2015,
              <https://www.rfc-editor.org/info/rfc7606>.

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/info/rfc8174>.

   [RFC8955]  Loibl, C., Hares, S., Raszuk, R., McPherson, D., and M.
              Bacher, "Dissemination of Flow Specification Rules",
              RFC 8955, DOI 10.17487/RFC8955, December 2020,
              <https://www.rfc-editor.org/info/rfc8955>.

   [RFC8956]  Loibl, C., Ed., Raszuk, R., Ed., and S. Hares, Ed.,
              "Dissemination of Flow Specification Rules for IPv6",
              RFC 8956, DOI 10.17487/RFC8956, December 2020,
              <https://www.rfc-editor.org/info/rfc8956>.

   [RFC9015]  Farrel, A., Drake, J., Rosen, E., Uttaro, J., and L.
              Jalil, "BGP Control Plane for the Network Service Header
              in Service Function Chaining", RFC 9015,
              DOI 10.17487/RFC9015, June 2021,
              <https://www.rfc-editor.org/info/rfc9015>.

   [RFC9117]  Uttaro, J., Alcaide, J., Filsfils, C., Smith, D., and P.
              Mohapatra, "Revised Validation Procedure for BGP Flow
              Specifications", RFC 9117, DOI 10.17487/RFC9117, August
              2021, <https://www.rfc-editor.org/info/rfc9117>.

   [RFC9184]  Loibl, C., "BGP Extended Community Registries Update",
              RFC 9184, DOI 10.17487/RFC9184, January 2022,
              <https://www.rfc-editor.org/info/rfc9184>.

   [RFC9582]  Snijders, J., Maddison, B., Lepinski, M., Kong, D., and S.
              Kent, "A Profile for Route Origin Authorizations (ROAs)",
              RFC 9582, DOI 10.17487/RFC9582, May 2024,
              <https://www.rfc-editor.org/info/rfc9582>.




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8.2.  Informative References

   [I-D.hares-idr-fsv2-more-ip-actions]
              Hares, S., "BGP Flow Specification Version 2 - More IP
              Actions", Work in Progress, Internet-Draft, draft-hares-
              idr-fsv2-more-ip-actions-03, 17 October 2024,
              <https://datatracker.ietf.org/doc/html/draft-hares-idr-
              fsv2-more-ip-actions-03>.

   [I-D.ietf-idr-flowspec-v2]
              Hares, S., Eastlake, D. E., Yadlapalli, C., and S.
              Maduschke, "BGP Flow Specification Version 2", Work in
              Progress, Internet-Draft, draft-ietf-idr-flowspec-v2-04,
              28 April 2024, <https://datatracker.ietf.org/doc/html/
              draft-ietf-idr-flowspec-v2-04>.

   [RFC3032]  Rosen, E., Tappan, D., Fedorkow, G., Rekhter, Y.,
              Farinacci, D., Li, T., and A. Conta, "MPLS Label Stack
              Encoding", RFC 3032, DOI 10.17487/RFC3032, January 2001,
              <https://www.rfc-editor.org/info/rfc3032>.

   [RFC6241]  Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed.,
              and A. Bierman, Ed., "Network Configuration Protocol
              (NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011,
              <https://www.rfc-editor.org/info/rfc6241>.

   [RFC8040]  Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF
              Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017,
              <https://www.rfc-editor.org/info/rfc8040>.

   [RFC8205]  Lepinski, M., Ed. and K. Sriram, Ed., "BGPsec Protocol
              Specification", RFC 8205, DOI 10.17487/RFC8205, September
              2017, <https://www.rfc-editor.org/info/rfc8205>.

   [RFC8206]  George, W. and S. Murphy, "BGPsec Considerations for
              Autonomous System (AS) Migration", RFC 8206,
              DOI 10.17487/RFC8206, September 2017,
              <https://www.rfc-editor.org/info/rfc8206>.

   [RFC8300]  Quinn, P., Ed., Elzur, U., Ed., and C. Pignataro, Ed.,
              "Network Service Header (NSH)", RFC 8300,
              DOI 10.17487/RFC8300, January 2018,
              <https://www.rfc-editor.org/info/rfc8300>.

   [RFC8402]  Filsfils, C., Ed., Previdi, S., Ed., Ginsberg, L.,
              Decraene, B., Litkowski, S., and R. Shakir, "Segment
              Routing Architecture", RFC 8402, DOI 10.17487/RFC8402,
              July 2018, <https://www.rfc-editor.org/info/rfc8402>.



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Author's Address

   Susan Hares
   Hickory Hill Consulting
   7453 Hickory Hill
   Saline, MI 48176
   United States of America
   Phone: +1-734-604-0332
   Email: shares@ndzh.com










































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