Filter-Based RIB Data Model
draft-hares-rtgwg-fb-rib-01

Versions: 00 01                                                         
I2RS working group                                              S. Hares
Internet-Draft                                                    Huawei
Intended status: Standards Track                                R. White
Expires: October 6, 2016                                        LinkedIn
                                                           April 4, 2016


                      Filter-Based RIB Data Model
                      draft-hares-rtgwg-fb-rib-01

Abstract

   This document defines a yang data model for a Filter-based Routing
   Information Base (RIB) Yang data model.  A routing system uses the
   Filter-based RIB to program FIB entries that process incoming packets
   by matching on multiple fields (n-tuple) within the packet and then
   performing a specified action on it.  The FB-RIB can also specify an
   action to forward the packet according to the FIB entries programmed
   using the RIBs of its routing instance.

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
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   This Internet-Draft will expire on October 6, 2016.

Copyright Notice

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   document authors.  All rights reserved.

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   to this document.  Code Components extracted from this document must



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   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
     1.1.  Definition of I2RS Filter Based RIB . . . . . . . . . . .   2
     1.2.  Requirements Language . . . . . . . . . . . . . . . . . .   3
     1.3.  Definitions and Acronyms  . . . . . . . . . . . . . . . .   3
     1.4.  Yang High Level (YHL) graphical form  . . . . . . . . . .   4
   2.  Where Filter-Based RIB Fits in Global RIBs  . . . . . . . . .   5
   3.  Proposed Structure for Filter-Based RIBs  . . . . . . . . . .   7
   4.  Yang High Level Structure for FB-RIBs . . . . . . . . . . . .   8
     4.1.  Top Level Yang Structure for ietf-fb-rib  . . . . . . . .   9
     4.2.  Filter-Based RIB structures . . . . . . . . . . . . . . .  10
   5.  yang models . . . . . . . . . . . . . . . . . . . . . . . . .  11
     5.1.  Filter-Based RIB types  . . . . . . . . . . . . . . . . .  11
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  11
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .  11
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  12
     8.1.  Normative References: . . . . . . . . . . . . . . . . . .  12
     8.2.  Informative References  . . . . . . . . . . . . . . . . .  12
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  13

1.  Introduction

   This document provides a yang module for flow filter n-tuple policy
   that is locally configured.  This flow filter policy has also been
   called Policy routing in some implementations.

   This document defines a yang data model for a Filter-based Routing
   Information Base (RIB) Yang data model.  A routing system uses the
   Filter-based RIB to program FIB entries that process incoming packets
   by matching on multiple fields within the packet and then performing
   a specified action on it.  The FB-RIB can also specify an action to
   forward the packet according to the FIB entries programmed using the
   RIBs of its routing instance.

1.1.  Definition of I2RS Filter Based RIB

   Filter-based routing is a technique used to make packet forwarding
   decisions based on a n-tuple filter that is matched to the incoming
   packets and the specified action.  It should be noted that that this
   is distinct from the static routes in the following RIBS:

   o  configured RIB created using static routes in
      [I-D.ietf-netmod-routing-cfg]



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   o  Extended static RIB defined in [I-D.acee-rtgwg-yang-rib-extend],

   o  Ephmeral Protocol Independent RIB defined in
      [I-D.ietf-i2rs-rib-info-model], or

   A Filter-Based RIB (Routing Information Base) is contained in a
   routing instance.  It contains a list of filters (match-action
   conditions), a list of interface the filter-based forwarding operates
   on.  Filter-based RIBs (FB-RIBs) operate only on the interface the
   FB-RIB are configured on.

   A Filter Based RIB uses packet forwarding policy.  If packet
   reception is considered an event, then the I2RS Filter-based RIB uses
   a minimalistic Event-Condition-Action policy.  A Filter-based RIB
   entry specifies matche filters for the fields in a packet (which may
   include layer 1 to layer 3 header fields, transport or application
   fields) or size of the packet or interface received on.  The matches
   are contained in an ordered list of filters which contain pairs of
   match condition-action (aka event-condition-action).

   If all matches fail, the default action is to forward the packet
   using FIB entries that were programmed by the default Routing
   Informational Base (RIB) manager configured in the Filter-Based RIB
   (FB-RB)

   Actions in the condition-action pair may impact forwarding or set
   something in the packet that will impact forwarding.  Policy actions
   are typically applied before applying QoS constraints since policy
   actions may override QoS constraint.

   The Filter-Based RIB resides in ephemeral state as does the I2RS RIB
   and I2RS topology models.

1.2.  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 [RFC2119]

   In this document, these words will appear with that interpretation
   only when in ALL CAPS.  Lower case uses of these words are not to be
   interpreted as carrying RFC-2119 significance.

1.3.  Definitions and Acronyms

   CLI

      Command Line Interface



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   FB-RIB

      Filter-Based Routing Information Base

   FB-Route

      The policy rules in the filter-based RIB are prescriptive of the
      Event-Condition-Action form which is often represented by if
      Condition then action.  All policy in the filter-based RIB are in
      a ordered list, ordered by "order-number".  Order number is
      similar to some CLI concepts of line number.

   Policy Group

      Policy Groups are groups of policy rules that are set-up for the
      convenience of operators who wish to link the rules connected to a
      particular client.

      *  Groups do not affect the order of policy rulies.

      *  The policy groups in the basic network policy
         [I-D.hares-i2rs-pkt-eca-data-model] allow grouping of policy by
         name.  This name allow easier management of customer-based or
         provider based filters.  This policy group is a second way to
         access certain policy rules on the policy rule list.

   RIB IM

      RIB Informational Model (RIB IM) [I-D.ietf-i2rs-rib-info-model]

   Routing instance

      A routing instance, in the context of the FB-FIB is a collection
      of RIBs, interfaces, and routing parameters.  A routing instance
      creates a logical slice of the router and allows different logical
      slices; across a set of routers; to communicate with each other.

1.4.  Yang High Level (YHL) graphical form

   The High-level Yang graphical representation uses the following
   symbols:

      Brackets "[" and "]" enclose list keys.

      Curly braces "{" and "}" contain names of optional features that
      make the corresponding node conditional.





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      Abbreviations before data node names: "rw" means configuration
      (read-write), "ro" state data (read-only), "-x" RPC operations,
      and "-n" notifications.

      Symbols after data node names: "?" means an optional node, "!" a
      container with presence, and "*" denotes a "list" or "leaf-list".

      Parentheses enclose choice and case nodes, and case nodes are also
      marked with a colon (":").

      Ellipsis ("...") stands for contents of subtrees that are not
      shown.

2.  Where Filter-Based RIB Fits in Global RIBs

   The Top-level Yang structure for a global FB-RIB types (similar to
   acl) is not defined.  The Filter-Based RIB should be defined under
   this structure under a routing instance.  The two things under this
   RIB would be: configured Filter-Based RIB (aka Policy routing), I2RS
   reboot Ephemeral Filter-Based RIB.  ACLs [I-D.ietf-netmod-acl-model]
   have the potential to be augmented to be included, but this version
   of this document does address that issue.

   The purpose of this section is illustrate why the flow specification
   policy installed in yang modules loaded into intended configuration
   needs to be able to be compared.  After demonstrating why this is
   needed, this section suggests a structure for filter-based RIBS.

   BGP's Flow Specification (BGP-FS) configures filter-based policy in
   the local BGP configuration, and passes this information in BGP
   packets (in NLRI and Extended Communities).  The BGP-FS YANG model
   [I-D.wu-idr-flowspec-yang-cfg] specifies the locally configuration,
   and the derived state that includes the BGP Flow Specifications
   received.  BGP-FS processing may install the locally configured BGP
   Flow specification in the local FB-RIB.  If it does, this policy is
   like any other locally configured policy.

   The BGP-FS may installed the flow policy received from a remote BGP
   peer and stored in derived state.  This policy has a different
   characteristics as it will disappear if the peer connection between
   the two peers drops, or if the peer changes the BGP-FS policy.  Due
   to the ephemeral nature of the BGP-FS, it should be installed unique.
   Otherwise, If the local configuration state changes, it cannot
   differentiate between the true configured state and the ephemeral
   states (I2RS ephemeral and BGP-session ephemeral).  Both I2RS
   ephemeral and BGP-session ephemeral policy will disappear upon a
   reboot.




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   ietf-fb-rib module
   +--rw routing-instance
      +--rw ietf-fb-rib
         +--rw default-instance-name string
         +--rw default-router-id rt:router-id
             +--rw config-fb-rib // config state
                uses fb-ribs
             +--rw I2rs-fb-rib  // ephemeral state
                uses fb-ribs
             +--rw BGP-FB-RIB   // Install derived
                uses fb-ribs    // BGP-FS policy state

       Figure 6: Global FB RIB Yang Structure

   I2RS architecture [I-D.ietf-i2rs-architecture] specifies that by
   default the Local configuration will win if the local configuration
   changes.  In the NETCONF/NETMOD language, the "last write wins".

   An example will help illustrate this:

      local configuration installs filter for IP-Dest=128.2/16, IP-
      SRC=192.5.7/24 DPORT=ALL drop in the running configuration, and
      then synchronously loads it to the intended configuration and
      applied configuration.

      I2RS installs an ephemeral filter for IP-Dest=128.2/16, IP-
      SRC=192.5.7/24 DPORT=125 forward intended configuration
      synchronously.

      BGP-FS processing installs BGP-FS policy for IP-Dest=128.2/16, IP-
      SRC=192.5.7/24 DPORT=125 forward, traffic-rate by bytes.

      local configuration install a filter for IP-Dest=128.2/16, IP-
      SRC=192.5.7/24, DPort=125, drop.  This local configuration policy
      would win over the I2RS policy and the BGP-FS.  The I2RS process
      is required to receive an event indicating the overwrite.  The
      BGP-FS process should also receive an event indicating an
      overwrite.

   The I2RS [I-D.ietf-i2rs-architecture] also allows that the preference
   between local-configuration and I2RS ephemeral state can be
   determined by operator-applied policy.  However, illustrations of
   this are out of scope for this version of this document.








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3.  Proposed Structure for Filter-Based RIBs

   There are three levels in the Filter-Based RIBs (FB-RIB) structure:

   o  a global FB-RIB structures,

   o  the common structure of the FB-RIB, and

   o  the groupings that make up the FB-RIB

   All structures have two types: configuration/ephemeral state and
   operational state.

   This yang model describes three types of FB-RIBS: configuration,
   I2RS, and BGP Flow Specification.  The configuration FB-RIB yang
   module is config state ("config true" and "ephemeral false") and
   survives a reboot.  The I2RS FB-RB yang model is reboot ephemeral
   ("config true" and "ephemeral true").  The BGP Flow Specification
   Filter-Based RIB stores policy which is received by the BGP peers,
   and can be considered policy configured as part of BGP infrastructure
   ("config true" and "peer-ephemeral true;")






























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   Configuration RIBS

   bgp-fs-fb-rib - is the BGP processes installation of
       the BGP Flow Specification (BGP-FS) policy rules
           from remote peers. Locally configured
           BGP-FS rules are configured in the BGP peer
           structure.

      +-----------------------------------------+
      |     routing instance                    |
      +-------|-------------|----------------|--+
              |             |                |
              |             |                |
    +---------|----+  +-----|-----+ +--------|-----+
    |config-fb-rib |  |i2rs-fb-rib| |bgp-fs-fb-rib |
    +------|-------+  +-----|------+ +------|------+
           |............:....|...............|
                        :  (uses common structures
                        :   in separate lists of FB-RIBs)
               +--------|----+
               |fb-ribs*     |
               |             |
               +--|----------+
                  |

     Figure 3: Routing instance with three types of
               Filter-FIB lists

4.  Yang High Level Structure for FB-RIBs

   The following section provides the high level yang structure diagrams
   for the following levels of structures for both config/ephemeral
   state and operationa.

   o  ietf-fb-rib - contains filter-based RIBS for config, I2RS FB-RIB,
      and BGP Flow Specification.

   o  fb-rib - that contains the structures for the filter-based
      grouping

   o  fb-rib-types - that contains the structures for groupings within
      the filter-based RIBS

   These structures are contained within the yang section in this draft.

   The packet-reception ECA policy yang module is contained in the draft
   [I-D.hares-i2rs-pkt-eca-data-model].




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   For those who desire more information regarding the logic behind the
   I2RS Filter-Based RIB, please see the Informational Model at:
   [I-D.kini-i2rs-fb-rib-info-model].

4.1.  Top Level Yang Structure for ietf-fb-rib

   The Top-level Yang structure for a global FB-RIB types (similar to
   acl) is not defined for filter-based RIBS.  The I2RS Filter-Based RIB
   should be defined under this structure under a routing instance.  The
   three things under this RIB would be: configured Filter-Based RIB
   (aka Policy routing), I2RS reboot Ephemeral Filter-Based RIB, and BGP
   Flow Specification's Filter-Based RIB.  All of these RIBs have
   similar actions.

   There are two types top-level structures for ietf-fb-ribs: config and
   operational state.

   The Top-level Yang structure for a global configuration of Filter-
   Based RIBs are:

   Augments rt:logical-network-elements:\
           :logical-network-element:network-instances: \
               network-instance

   ietf-fb-rib module
     +--rw ietf-fb-rib
        +--rw default-instance-name string
        +--rw default-router-id rt:router-id
        +--rw config-fb-ribs
               if-feature "config-filter-based-RIB";
           uses fb-ribs;
        +--rw i2rs-fb-ribs
                     if-feature "I2RS-filter-based-RIB";
                     uses fb-rib-t:fb-ribs;
        +--rw bgp-fs-fb-ribs
                    if-feature "BGP-FS-filter-based-RIB";
                     uses fb-rib-t:fb-ribs;

       Figure 5: configuration state

   The Top-level Yang structure for a global operational state of
   Filter-Based RIBs are:









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   Augments rt:logical-network-elements:\
           :logical-network-element:network-instances: \
               network-instance

   ietf-fb-rib module
     +--rw ietf-fb-rib-opstate
       +--rw default-instance-name string
       +--rw default-router-id rt:router-id
           +--rw config-fb-rib-opstate
                     if-feature "config-filter-based-RIB";
                     uses fb-rib-t:fb-ribs-oper-status;
           +--rw i2rs-fb-rib-opstate {
                     if-feature "I2RS-filter-based-RIB";
                     uses fb-rib-t:fb-ribs-oper-status;
           +--rw bgp-fs-fb-rib-opstate
                     if-feature "BGP-FS-filter-based-RIB";
                     uses fb-rib-t:fb-ribs-oper-status;

       Figure 5: operational state

4.2.  Filter-Based RIB structures

   The Top-level yang structures at the Filter-Based RIB level have two
   types: configuration and operational state.

   The Top-level Yang structure for the FB-RIB types is:

























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    module: fb-rib-types:
    +--rw fb-ribs
       +--rw fb-rib* [rib-name]
       |  +--rw rib-name string
       |  |  rw fb-type identityref / ephemeral or not
       |  +--rw rib-afi rt:address-family
       |  +--rw fb-rib-intf* [name]
       |  |  +--rw name string
       |  |  +--rw intf if:interface
       |  +--rw default-rib
       |  |  +--rw rt-rib rt:routing:routing-instance:name
       |  |  +--rw config-rib string;  // config rib name
       |  |  +--rw i2rs-rib:routing-instance:name
       |  |  +--rw i2rs-rib string;   //ephemeral rib name
       |  |  +--rw bgp-instance-name string
       |  |  +--rw bgp-rib  string    //session ephemeral
       |  +--rw fb-rib-refs
       |  |  +--rw fb-rib-update-ref uint32 /count of writes
       |  +--rw instance-using*
       |  |   device:networking-instance:networking-instance-name
       |  +--use pkt-eca:pkt-eca-policy-set

             Figure 6: FB RIB Type Structure

   HIgh Level Yang

   +--rw fb-ribs-oper-status
      +--rw fb-rib-oper-status* [fb-rib-name]
            uses pkt-eca:pkt-eca-opstate

5.  yang models

5.1.  Filter-Based RIB types

   Yang model is contained in draft-hares-i2rs-fb-rib-data-model-01.txt

   Please see this draft for the data model.

6.  IANA Considerations

   TBD

7.  Security Considerations

   A I2RS RIB is ephemeral data store that will dyanamically change
   traffic paths set by the routing configuration.  An I2RS FB-RIB
   provides dynamic Event-Condition-Action policy that will further
   change the operation of forwarding by allow dyanmic policy and



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   ephemeral RIBs to alter the traffic paths set by routing
   configuration.  Care must be taken in deployments to use the
   appropriate security and operational control to make use of the tools
   the I2RS RIB and I2RS FB-RIB provide.

8.  References

8.1.  Normative References:

   [I-D.acee-rtgwg-yang-rib-extend]
              Lindem, A. and Y. Qu, "RIB YANG Data Model", draft-acee-
              rtgwg-yang-rib-extend-01 (work in progress), March 2016.

   [I-D.hares-i2rs-fb-rib-data-model]
              Hares, S., Kini, S., Dunbar, L., Krishnan, R., Bogdanovic,
              D., and R. White, "Filter-Based RIB Data Model", draft-
              hares-i2rs-fb-rib-data-model-03 (work in progress), March
              2016.

   [I-D.hares-i2rs-pkt-eca-data-model]
              Hares, S., Wu, Q., and R. White, "Filter-Based Packet
              Forwarding ECA Policy", draft-hares-i2rs-pkt-eca-data-
              model-02 (work in progress), February 2016.

   [I-D.ietf-i2rs-rib-data-model]
              Wang, L., Ananthakrishnan, H., Chen, M.,
              amit.dass@ericsson.com, a., Kini, S., and N. Bahadur, "A
              YANG Data Model for Routing Information Base (RIB)",
              draft-ietf-i2rs-rib-data-model-05 (work in progress),
              March 2016.

   [I-D.ietf-netmod-routing-cfg]
              Lhotka, L. and A. Lindem, "A YANG Data Model for Routing
              Management", draft-ietf-netmod-routing-cfg-21 (work in
              progress), March 2016.

   [I-D.wu-idr-flowspec-yang-cfg]
              Wu, N., Zhuang, S., and A. Choudhary, "A YANG Data Model
              for Flow Specification", draft-wu-idr-flowspec-yang-cfg-02
              (work in progress), October 2015.

8.2.  Informative References

   [I-D.ietf-i2rs-architecture]
              Atlas, A., Halpern, J., Hares, S., Ward, D., and T.
              Nadeau, "An Architecture for the Interface to the Routing
              System", draft-ietf-i2rs-architecture-13 (work in
              progress), February 2016.



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   [I-D.ietf-i2rs-rib-info-model]
              Bahadur, N., Kini, S., and J. Medved, "Routing Information
              Base Info Model", draft-ietf-i2rs-rib-info-model-08 (work
              in progress), October 2015.

   [I-D.ietf-i2rs-usecase-reqs-summary]
              Hares, S. and M. Chen, "Summary of I2RS Use Case
              Requirements", draft-ietf-i2rs-usecase-reqs-summary-02
              (work in progress), March 2016.

   [I-D.ietf-netmod-acl-model]
              Bogdanovic, D., Koushik, K., Huang, L., and D. Blair,
              "Network Access Control List (ACL) YANG Data Model",
              draft-ietf-netmod-acl-model-07 (work in progress), March
              2016.

   [I-D.kini-i2rs-fb-rib-info-model]
              Kini, S., Hares, S., Dunbar, L., Ghanwani, A., Krishnan,
              R., Bogdanovic, D., and R. White, "Filter-Based RIB
              Information Model", draft-kini-i2rs-fb-rib-info-model-03
              (work in progress), February 2016.

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

Authors' Addresses

   Susan Hares
   Huawei
   7453 Hickory Hill
   Saline, MI  48176
   USA

   Email: shares@ndzh.com


   Russ White
   LinkedIn

   Email: russ@riw.us









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