Internet DRAFT - draft-lin-idr-cats-flowspec-ts
draft-lin-idr-cats-flowspec-ts
IDR C. Lin
Internet Draft New H3C Technologies
Intended status: Standards Track H. Yao
Expires: September 3, 2024 China Mobile
March 4, 2024
BGP Flowspec for Computing-Aware Traffic Steering
draft-lin-idr-cats-flowspec-ts-00
Abstract
A BGP Flow Specification is an n-tuple consisting of several
matching criteria that can be applied to IP traffic. Computing-Aware
Traffic Steering (CATS) is a framework, This document specifies a
new BGP Flow Spec Component Type in order to support CATS traffic
forwarding.
Status of this Memo
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This Internet-Draft will expire on September 3, 2024.
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Table of Contents
1. Introduction...................................................3
2. Requirements Language..........................................3
3. Terminology....................................................4
4. Flow Specifications for CATS ..................................5
5. Component Type for CATS .......................................5
5.1. CS-ID - Type TBD1.........................................5
6. Traffic Filtering..............................................6
6.1. Traffic Filtering Actions.................................6
7. IANA Considerations............................................6
7.1. Flow Spec Component - CS-ID...............................6
7.2. Extended Community Flow Specification Actions.............6
8. Security Considerations........................................7
9. References.....................................................7
9.1. Normative References......................................7
Authors' Addresses................................................8
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1. Introduction
A Flow Specification (Flow Spec) is an n-tuple consisting of several
matching criteria that can be applied to IP traffic [RFC8955]. The
Flow Spec conveys match conditions (each may include several
components) which are encoded using MP_REACH_NLRI and
MP_UNREACH_NLRI attributes [RFC4760], while the associated actions
such as redirect and traffic marking are encoded in BGP Extended
Communities [RFC4360][RFC5701]. The IPv4 NLRI component types and
traffic filtering actions sub-types are described in [RFC8955],
while the IPv6 related are described in [RFC8956].
[I-D.ietf-idr-flowspec-l2vpn] extends the flow-spec rules and
actions for Ethernet Layer 2 and L2VPN. The corresponding (AFI,
SAFI) pairs are defined by IANA, respectively. [I-D.hares-idr-
flowspec-v2] specifies BGP Flow Specification Version 2.
Computing-Aware Traffic Steering (CATS) is introduced in [draft-
ldbc-cats-framework-05].
The CS-ID is a globally unique object in the network, which can be a
server's IP address, an SR label, or a simple unsigned numerical
value.
In CATS network, the C-PS component performs path selection based on
the CS-ID and forwards service traffic according to the selected
path.
This document specifies a new BGP Flow Spec Component Type to
support CATS traffic filtering. Traffic is classified and mapped to
the corresponding CS-ID using BGP Flow Spec rules, and path
selection is then performed based on the CS-ID. BGP Flow Spec
implements functions similar to the C-TC component.
On the other hand, BGP Flow Spec can also use CS-ID as a filtering
criterion. For the matched traffic, it forwards based on the actions
specified by BGP Flow Spec, replacing the path selection function of
C-PS. It also specifies traffic filtering actions to enable the
creation of the CS-ID in the outer tunnel encapsulation when matched
to the corresponding Flow Spec rules.
2. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in
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BCP 14 RFC 2119 [RFC2119] RFC 8174 [RFC8174] when, and only when,
they appear in all capitals, as shown here.
3. Terminology
This document makes use of the following terms:
Client: An endpoint that is connected to a service provider network.
Computing-Aware Traffic Steering (CATS): A traffic
engineeringapproach [I-D.ietf-teas-rfc3272bis] that takes into
account the dynamic nature of computing resources and network
state to optimize service-specific traffic forwarding towards a
given service contact instance. Various relevant metrics may be
used to enforce such computing-aware traffic steering policies.
CATS Service ID (CS-ID): An identifier representing a service.
CATS-Forwarder: A network entity that makes forwarding decisions
based on CATS information to steer traffic specific to a service
request towards a corresponding yet selected service contact
instance. The selection of a service contact instance relies upon
a multi-metric path computation.
Ingress CATS-Forwarder: An entity that steers service-
specifictraffic along a CATS-computed path that leads to an Egress
CATS-Forwarder that connects to the most suitable service site
that host the service contact instance selected to satisfy the
initial service request.
Egress CATS-Forwarder: An entity that is located at the end of a
CATS-computed path and which connects to a CATS-serviced site.
CATS Path Selector (C-PS): A functional entity that computes and
selects paths towards service locations and instances and which
accommodates the requirements of service requests. Such a path
computation engine takes into account the service and network
status information.
CATS Network Metric Agent (C-NMA): A functional entity that is
responsible for collecting network capabilities and status, and
for reporting them to a C-PS.
CATS Traffic Classifier (C-TC): A functional entity that is
responsible for determining which packets belong to a traffic flow
for a particular service request. It is also responsible for
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forwarding such packets along a C-PS computed path that leads to
the relevant service contact instance.
Flow Spec: Flow Specification
BGP-FS: Border Gateway Protocol (BGP) Flow Specification (FS)
4. Flow Specifications for CATS
The Flow Spec for CATS is shown in Figure 1, that is, the Controller
is used to set up BGP connection with the policy enforcement points
in CATS network.
+------------------+
/------| Controller |-----\
/ +------------------+ \
+------+ FS / | \ FS +------+
|Client|-\ / FS FS FS \ /-|Server|
+------+ \ +-/------+ +--/------|------\-----+ +--\-----+ / +------+
\-|Ingress | | | |Egress |-/
|CATS-FWD|--| CATS Network |--|CATS-FWD|
/-| | | | | |-\
+------+ / +--------+ +----------------------+ +--------+ \ +------+
|Client|-/ \-|Server|
+------+ +------+
Figure 1. Flow Spec for CATS
5. Component Type for CATS
The IPv4 NLRI component types are defined in [RFC8955], while the
IPv6 related are specified in [RFC8956]. This document defines a
new component type for CATS.
After C-TC performs traffic classification and maps the
corresponding CS-ID, and before the original action of path
selection via C-PS based on CS-ID, Ingress CATS-Forwarder first
searches for Flow-Spec routes based on the CS-ID. If a match is
found, the traffic is forwarded directly according to the Flow-Spec
route.
5.1. CS-ID - Type TBD1
Encoding: <type (1 octet), length (1 octet), CS-ID(variable)>
Defines the CS-ID to match.
type (1 octet): This indicates the new component type TBD1.
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length (1 octet): This indicates the length of the CS-ID.
CS-ID (variable): This indicates the CS-ID that is used for the
match.
6. Traffic Filtering
On the Ingress CATS-Forwarder, before performing traffic
classification, the traffic is filtered based on the traffic
characteristics according to BGP Flow-Spec rules. If a corresponding
rule is matched, the traffic is then mapped to the corresponding CS-
ID.
The actions are defined in this section.
6.1. Traffic Filtering Actions
+==================+=====================+========================+
| Community 0xttss | action | encoding |
| Sub-Type | | |
+==================+=====================+========================+
| TBD2 | traffic-marking-cats|CS-ID |
+------------------+---------------------+------------------------+
7. IANA Considerations
7.1. Flow Spec Component - CS-ID.
IANA is requested to assign a value in the Flow Specification
Component Types Registry as follows:
+=======+====================+===============+
| Value | Name | Reference |
+=======+====================+===============+
| TBD1 | CS-ID | This document |
+-------+--------------------+---------------+
7.2. Extended Community Flow Specification Actions
The Extended Community Flow Specification Actions are defined in
this document and it is requested that corresponding Sub-Types as
shown in the following table be assigned.
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+============+==============================+===============+
| Sub-Type | Name | Reference |
| Value | | |
+============+==============================+===============+
| TBD2 | traffic-marking-cats | This document |
+------------+------------------------------+---------------+
8. Security Considerations
TBD
9. References
9.1. Normative References
TBD
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Authors' Addresses
Changwang Lin
New H3C Technologies
China
Email: linchangwang.04414@h3c.com
Huijuan Yao
China Mobile
No.32 XuanWuMen West Street
Beijing
100053
China
Email: yaohuijuan@chinamobile.com
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