Internet DRAFT - draft-hares-rtgwg-fb-rib
draft-hares-rtgwg-fb-rib
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
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This Internet-Draft will expire on October 6, 2016.
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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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