openconfig-policy-forwarding

Organization:

OpenConfig working group

Module:

openconfig-policy-forwarding

Version:

2024-11-14

File:

openconfig-policy-forwarding.yang

Abstract:

This module defines configuration and operational state data relating to policy-based forwarding. Policy-based forwarding is uti...

Contact:

OpenConfig working group
www.openconfig.net

Check for an additional details:

YANG Catalog

Description:

This module defines configuration and operational state data
relating to policy-based forwarding. Policy-based forwarding is
utilised when a system chooses how to forward packets (including
applying data-plane operations such as encapsulation or
decapsulation) based on policies other than destination L2 or L3
header. Typically, systems may implement:

- IP policy-based routing, where routing may be done based on the
source plus destination of an IP packet; information within the
L4 header; or some combination of both.
- Encapsulation or decapsulation based on certain policy
information - for example, matching particular IP destinations
and decapsulating GRE headers.
- Class-based selection of egress routes - such as class-based
selection of an egress MPLS path.

The policies that are defined in this model are applied to a
particular ingress context of a network element (e.g., interface)
and are defined to apply following other interface policy such as
QoS classification and access control lists.

This module defines:

- policy-forwarding
|
|--- policies
| |-- policy
| |-- [match criteria] How packets are defined to
| | match policy.
| |-- [forwarding-action] How packets matching should
| be forwarded.
|--- interfaces
| |-- interfaces
| | -- apply-forwarding-policy Forwarding policy to
| used on the interface.
|--- path-selection-groups
|-- path-selection-group A group of forwarding resources
that are grouped for purposes
of next-hop selection.

A forwarding-policy specifies the match criteria that it intends
to use to determine the packets that it reroutes - this may
consist of a number of criteria, such as DSCP. The match criteria
is specified as rules. If no rules are specified, then the policy
will match all packets.

The action of the policy results in a forwarding action being applied
to matching packets. For example, decapsulating the packet from a GRE
header. In order to enact the policy based on particular interfaces -
the forwarding-policy is applied to an interface via referencing it
within an 'apply-forwarding-policy' statement associated with an
interface.

A policy-forwarding rule with no action should be treated as an error.

In some cases (e.g., Class-Based Tunnel Selection) the forwarding
action does not resolve to a single egress action, and rather
normal forwarding rules are to be applied but considering a subset
of forwarding resources. In these cases, a path-selection-group
can be created, referencing the subset of forwarding paths that
should be used for the egress selection. In the case that a subset
of MPLS LSPs are eligible for, say, DSCP 46 marked packets, a
path-selection-group is created, referencing the subset of LSPs.
The forwarding action of the corresponding policy is set to
PATH_GROUP and references the configured group of LSPs.