Interdomain Routing Working Group M. Liu, Ed.
Internet-Draft Y. Wang, Ed.
Intended status: Standards Track Huawei
Expires: August 31, 2020 February 28, 2020
A New Definition of the Flowspec IFIT Wide Community
draft-liu-idr-flowspec-ifit-00
Abstract
BGP Flowspec mechanism propogates both flow specification information
and traffic filtering actions by making use of the BGP policy
framework. In this document, authors only add the requirements of
one new IFIT application [I-D.song-opsawg-ifit-framework] and specify
the encoding format of a new BGP Extended Community to propagate In-
situ flow information telemetry(IFIT) actions so as to address the
deployment challenges of IPv6 unicast and VPNv6 unicast on-path flow
information telemetry automatically.
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].
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 August 31, 2020.
Copyright Notice
Copyright (c) 2020 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Definitions of Terms Used in This Memo . . . . . . . . . 3
2. IFIT Application . . . . . . . . . . . . . . . . . . . . . . 3
3. Flowspec IFIT Wide Community . . . . . . . . . . . . . . . . 4
3.1. IFIT Action Community Value . . . . . . . . . . . . . . . 4
3.2. IFIT Action Atoms . . . . . . . . . . . . . . . . . . . . 5
3.2.1. IOAM Pre-allocated Trace Option Atom Sub-TLV . . . . 5
3.2.2. IOAM Incremental Trace Option Atom Sub-TLV . . . . . 6
3.2.3. IOAM DEX Trace Option Atom Sub-TLV . . . . . . . . . 7
3.2.4. IOAM Edge-to-Edge Option Atom Sub-TLV . . . . . . . . 9
3.2.5. Enhanced Alternate Marking Option Atom Sub-TLV . . . 9
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10
4.1. Registered Type 1 BGP Wide Communities Community Types . 10
4.2. BGP Community Container Atoms Types . . . . . . . . . . . 10
5. Security Considerations . . . . . . . . . . . . . . . . . . . 11
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 11
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 11
7.1. Normative References . . . . . . . . . . . . . . . . . . 11
7.2. Informative References . . . . . . . . . . . . . . . . . 11
Appendix A. An Appendix . . . . . . . . . . . . . . . . . . . . 12
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 12
1. Introduction
A family of on-path flow telemetry techniques being referred in
[I-D.song-opsawg-ifit-framework], are emerging, which can provide
flow information on the entire forwarding path on a per-packet basis
in real time. we categorize these on-path telemetry echniques as the
hybrid OAM type I according to the classification defined in
[RFC7799]. These techniques are invaluable for application-aware
network operations not only in data center and enterprise networks
but also in carrier networks which may cross multiple domains, which
are important for user SLA compliance, service path enforcement,
fault diagnosis, and network resource optimization. In IFIT
reflection-loop architecture [I-D.song-opsawg-ifit-framework], an
IFIT application would pick a suite of telemetry tecchniques based on
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its requirements and apply an initial technique to the data plane.
Then the IFIT head nodes are configured to decide the initial target
flows/packets and telemetry data set, the encapsulation and tunneling
scheme based on the underlying network architecture. And the IFIT-
capable nodes are configured to decide the inital telemetry data
export policy.
As we know, Dissemination of Flow Specification Rules
[I-D.ietf-idr-rfc5575bis] provides a protocol extension for
propagation of traffic flow information for the purpose of rate
limiting, filtering, shaping, classifying or redirecting. BGP
extended community encoding formats can be used to propagate traffic
filtering actions along with the flow specification NLRI. Those
traffic filtering actions encode actions a routing system can take if
the packet matches the flow specifications. Meanwhile, the other
document [I-D.ietf-idr-flow-spec-v6] extends
[I-D.ietf-idr-rfc5575bis] and defines changes to it in order to make
it also usable and applicable to IPv6 data packets.
From an operational perspective, the utilization of BGP Flowspec as
the carrier for the specific flow information allows a network
service provider to reuse BGP route distribute infrastructure.
But the former document defines these traffic filter actions by
extending the BGP extended community value which are formatted into
only 6-octet fixed length of data. Concerning actions of variable
IFIT option-types and different parameters, this document extends the
wide BGP communities [I-D.ietf-idr-wide-bgp-communities-05] to define
the IFIT action.
1.1. Definitions of Terms Used in This Memo
IFIT: in-situ Flow Information Telemetry
NLRI: Network Layer Reachability Information
2. IFIT Application
The IFIT applications, which enable the future autonomous network
operation, will pick one of proper in-situ telemetry techniques and
apply a flow, packet, and data selection policy to monitor the
specific traffic flow for application-aware network operation. In
current deployments, there have been relatively static methods, ACL-
like CLI and Netconf with YANG model to enable the specific flow or
packets from the target flow to be monitored on the relevant IFIT-
capable nodes.
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With the evolution of intent-based and automatic network operation,
and the trends of network virtualization, network convergence, and
packet-optical integration, future data plane telemetry will support
an on-demand and interactive fashion. Flexibility and extensibility
of data defining and acquiring must be considered. Therefore,
flexible configurations and actions need to be deployed based on the
real-time telemetry data analysis results and different application
requirements.
Then BGP Flowspec dynamic mechanism is preferred in the closed-loop
network telemetry system, which is going to add a new Traffic IFIT
Action value of BGP Wide Community to closely monitor the relevant
flows in real time that matches the flow specification's Network
Layer Reachability Information (NLRI) defined in [I-D.ietf-idr-
rfc5575bis] and [I-D.ietf-idr-flow-spec-v6].
In most cases, the IFIT application does not require Next Hop
information that shall be encoded as a 0-octet length Next Hop in the
MP_REACH_NLRI attribute.
According to the IOAM attribute, there is no disagreement between
IFIT action and the other defined traffic filtering actions.
3. Flowspec IFIT Wide Community
This section defines a new community value in BGP wide community for
IFIT action and extends optional lists of Atoms that encode
parameters of IFIT actions in accordance with different IFIT option
types.
Container Type 1, BGP Wide Community is defined in
[I-D.ietf-idr-wide-bgp-communities-05] .
3.1. IFIT Action Community Value
The Type 1 BGP Community Container, the BGP Wide Community, is of
variable size (but minimum length 12). The Community Value, in the
first 4-octets of a fixed 12-octets Wide Community header, indicates
what set of actions a router is requested to take upon reception of a
route containing this community. Then for this new type-IFIT action,
IANA is requested to allocate a new value in the corresponding
registry:
Name Community Value
---- ----------
IFIT Action TBD
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3.2. IFIT Action Atoms
The BGP Wide Community Parameter(s) TLV (Sub-Type 3) contains a list
of Atoms. Atoms are encoded as TLVs described in section 5 of
[I-D.ietf-idr-wide-bgp-communities-05]. The TLV types are to be
assigned by IANA registry. The Length represents the length of the
"Value" field in octets. The Value field contains the TLV value.
In IFIT architecture, there are a few of option types available for
the specified traffic flow, e.g. IOAM pre-allocated/incremental
trace, IOAM DEX trace, E2E ,POT etc. As different IFIT option types
have different formats of parameters, following defines new Atoms in
accordance with different IFIT option types.
Supported format of the IFIT action TLVs can be:
Type xx: IOAM Pre-allocated Trace Option
Type xx: IOAM Incremental Trace Option
Type xx: IOAM DEX Trace Option
Type xx: IOAM Edge-to-Edge Option
Type xx: Enhanced Alternate Marking Option
In the following sections, the different IFIT action option types of
Atoms will be presented.
3.2.1. IOAM Pre-allocated Trace Option Atom Sub-TLV
The IOAM tracing data is expected to be collected at every node that
a packet traverses to ensure visibility into the entire path a packet
takes within an IOAM domain. The pre-allocated tracing option will
create pre-allocated space for each node to populate its information.
The format of IOAM pre-allocated trace option sub-TLV is defined as
follows:
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+---------------------------------------------------------------+
| Type | Length | NamespaceID |
| | | high |
+---------------------------------------------------------------+
| NamespaceID | IOAM Trace Type |
| Low | |
+---------------------------------------------------------------+
| Flags | Rsvd |
| | |
+---------------+
Fig. 1 IOAM Pre-allocated Trace Option Sub-TLV
Where:
Type: to be assigned by IANA.
Length: the total length of the value field not including Type and
Length fields.
Namespace ID: A 16-bit identifier of an IOAM-Namespace. The
definition is the same as described in section 4.4
of[I-D.ietf-ippm-ioam-data] .
IOAM Trace Type: A 24-bit identifier which specifies which data types
are used in the node data list. The definition is the same as
described in section 4.4 of [I-D.ietf-ippm-ioam-data].
Flags: A 4-bit field. The definition is the same as described in [I-
D.ietf-ippm-ioam-flags] and section 4.4 of [I-D.ietf-ippm-ioam-data].
Rsvd: A 4-bit field reserved for further usage. It MUST be zero.
3.2.2. IOAM Incremental Trace Option Atom Sub-TLV
The incremental tracing option contains a variable node data fields
where each node allocates and pushes its node data immediately
following the option header.
The format of IOAM incremental trace option sub-TLV is defined as
follows:
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+---------------------------------------------------------------+
| Type | Length | NamespaceID |
| | | high |
+---------------------------------------------------------------+
| NamespaceID | IOAM Trace Type |
| Low | |
+---------------------------------------------------------------+
| Flags | Rsvd |
| | |
+---------------+
Fig. 2 IOAM Incremental Trace Option Sub-TLV
Where:
Type: to be assigned by IANA.
Length: the total length of the value field not including Type and
Length fields.
All the other fields definistion is the same as the pre-allocated
trace option sub-TLV in section 3.2.1.
3.2.3. IOAM DEX Trace Option Atom Sub-TLV
The DEX option is used as a trigger to export IOAM data to a
collector. Moreover, IOAM nodes MAY send exported data for all
traversing packets that carry the DEX option, or MAY selectively
export data only for a subset of these packets. The DEX option
specifies which data fields should be exported to the collector, as
specified in Section 3.2 of [I-D.ioamteam-ippm-ioam-direct-export].
The format of IOAM DEX Trace option sub-TLV is defined as follows:
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-----------------------------------------------+
| Type | Length |
| | |
+---------------------------------------------------------------+
| NamespaceID | Flags |
| | |
+---------------------------------------------------------------+
| IOAM-Trace-Type | Rsvd |
| | |
+---------------------------------------------------------------+
| FlowID(Optional) |
| |
+---------------------------------------------------------------+
| Sequence Number(Optional) |
| |
+---------------------------------------------------------------+
Fig. 3 IOAM DEX Trace Option Sub-TLV
Where:
Type: to be assigned by IANA.
Length: the total length of the value field not including Type and
Length fields.
Namespace-ID: a 16-bit identifier of the IOAM namespace, as defined
in section 4.4 of [I-D.ietf-ippm-ioam-data] .
Flags: a 16-bit field, comprised of 16 one-bit subfields. Flags are
allocated by IANA, as defined in Section 4.2 of
[I-D.ioamteam-ippm-ioam-direct-export] .
IOAM-Trace-Type: a 24-bit identifier which specifies which data
fields should be exported. The format of this field is as defined in
section 4.4 of[I-D.ietf-ippm-ioam-data]
Rsvd: this field SHOULD be ignored by the receiver.
Flow ID: a 32-bit flow identifier, as defined in section 3.2 of
[I-D.ioamteam-ippm-ioam-direct-export]
Sequence Number: a 32-bit sequence number , as defined in section 3.2
of [I-D.ioamteam-ippm-ioam-direct-export] .
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3.2.4. IOAM Edge-to-Edge Option Atom Sub-TLV
The IOAM edge to edge option is to carry data that is added by the
IOAM encapsulating node and interpreted by IOAM decapsulating node.
The format of IOAM edge-to-edge option sub-TLV is defined as follows:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-----------------------------------------------+
| Type | Length |
| | |
+---------------------------------------------------------------+
| NamespaceID | IOAM E2E Type |
| | |
+---------------------------------------------------------------+
Fig. 4 IOAM Edge-to-Edge Option Sub-TLV
Where:
Type: to be assigned by IANA.
Length: the total length of the value field not including Type and
Length fields.
Namespace ID: A 16-bit identifier of an IOAM-Namespace. The
definition is the same as described in section 4.6
of[I-D.ietf-ippm-ioam-data].
IOAM E2E Type: A 16-bit identifier which specifies which data types
are used in the E2E option data. The definition is the same as
described in section 4.6 of [I-D.ietf-ippm-ioam-data].
3.2.5. Enhanced Alternate Marking Option Atom Sub-TLV
The Alternate Marking [RFC8321]technique is an hybrid performance
measurement method and can be used to measure packet loss, latency,
and jitter on live traffic because it is based on marking consecutive
batches of packets.
The Enhanced Alternate Marking (EAM)
[I-D.zhou-ippm-enhanced-alternate-marking] defines data fields for
the alternate marking with enough space, in particular for Postcard-
based Telemetry. More information can be considered within the
alternate marking field to facilitate the efficiency and ease the
deployment.
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The format of EAM sub-TLV is defined as follows:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+---------------+-------------------------------+
| Type | Length |
| | |
+---------------+-----------------------+-------+-------+-------+
| FlowMonID | Period | Rsvd |
| | | |
+---------------------------------------+---------------+-------+
Fig. 5 Enhanced Alternate Marking Option Sub-TLV
Where: Type: to be assigned by IANA.
Length: the total length of the value field not including Type and
Length fields.
FlowMonID: A 20-bit identifier to uniquely identify a monitored flow
within the measurement domain. The definition is the same as
described in section 2 of [I-D.zhou-ippm-enhanced-alternate-marking].
Period: Time interval between two alternate marking period. The unit
is second.
Rsvd: A 4-bit field reserved for further usage. It MUST be zero.
4. IANA Considerations
4.1. Registered Type 1 BGP Wide Communities Community Types
For the new type-IFIT action, this document requests IANA to allocate
a new value in the corresponding registry named " Registered Type 1
BGP Wide Community Community Types":
+-------------+----------------+
| Name | Community Type |
+-------------+----------------+
| IFIT Action | TBD |
+-------------+----------------+
4.2. BGP Community Container Atoms Types
This document requests IANA to define new Atoms types for IFIT action
option types in registry named: "BGP Community Container Atom Types":
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Name Type Value
----- ----------
IOAM Pre-allocated Trace Option TBD
IOAM Incremental Trace Option TBD
IOAM DEX Trace Option TBD
IOAM Edge-to-Edge Option TBD
Enhanced Alternate Marking TBD
5. Security Considerations
No new security issues are introduced to the BGP protocol by this
specification over the security considerations in [I-D.ietf-idr-
rfc5575bis].
6. Acknowledgements
7. References
7.1. Normative References
[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>.
[RFC7799] "Active and Passive Metrics and Methods (with Hybrid Types
In-Between)", <https://www.rfc-editor.org/info/rfc7799>.
7.2. Informative References
[I-D.ietf-idr-flow-spec-v6]
"Dissemination of Flow Specification Rules for IPv6",
<https://datatracker.ietf.org/doc/draft-ietf-idr-flow-
spec-v6/>.
[I-D.ietf-idr-rfc5575bis]
"Dissemination of Flow Specification Rules",
<https://datatracker.ietf.org/doc/draft-ietf-idr-
rfc5575bis/>.
[I-D.ietf-idr-wide-bgp-communities-05]
"BGP Community Container Attribute",
<https://datatracker.ietf.org/doc/draft-ietf-idr-wide-bgp-
communities/>.
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[I-D.ietf-ippm-ioam-data]
"Data Fields for In-situ OAM",
<https://datatracker.ietf.org/doc/draft-ietf-ippm-ioam-
data/>.
[I-D.ioamteam-ippm-ioam-direct-export]
"In-situ OAM Direct Exporting",
<https://datatracker.ietf.org/doc/draft-ioamteam-ippm-
ioam-direct-export/>.
[I-D.song-opsawg-ifit-framework]
"In-situ Flow Information Telemetry Framework",
<https://datatracker.ietf.org/doc/draft-song-opsawg-ifit-
framework/>.
[I-D.zhou-ippm-enhanced-alternate-marking]
"Enhanced Alternate Marking Method",
<https://datatracker.ietf.org/doc/draft-zhou-ippm-
enhanced-alternate-marking/>.
Appendix A. An Appendix
Authors' Addresses
Min Liu (editor)
Huawei
156 Beiqing Rd., Haidian District
Beijing
China
Email: lucy_liumin@huawei.com
Yali Wang (editor)
Huawei
156 Beiqing Rd., Haidian District
Beijing
China
Email: wangyali11@huawei.com
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