Network Service Header TLVs
draft-ietf-sfc-nsh-tlv-02
The information below is for an old version of the document.
| Document | Type |
This is an older version of an Internet-Draft that was ultimately published as RFC 9263.
|
|
|---|---|---|---|
| Authors | Yuehua Wei , Uri Elzur , Sumandra Majee | ||
| Last updated | 2020-03-04 (Latest revision 2019-12-16) | ||
| RFC stream | Internet Engineering Task Force (IETF) | ||
| Formats | |||
| Reviews | |||
| Additional resources | Mailing list discussion | ||
| Stream | WG state | WG Document | |
| Document shepherd | (None) | ||
| IESG | IESG state | Became RFC 9263 (Proposed Standard) | |
| Consensus boilerplate | Unknown | ||
| Telechat date | (None) | ||
| Responsible AD | (None) | ||
| Send notices to | (None) |
draft-ietf-sfc-nsh-tlv-02
SFC Y. Wei, Ed.
Internet-Draft ZTE Corporation
Intended status: Standards Track U. Elzur
Expires: September 4, 2020 Intel
S. Majee
Caber systems inc
March 3, 2020
Network Service Header TLVs
draft-ietf-sfc-nsh-tlv-02
Abstract
This draft describes Network Service Header (NSH) MD-Type 2 metadata
TLVs that can be used within a service function path.
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
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on September 4, 2020.
Copyright Notice
Copyright (c) 2020 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
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.
Wei, et al. Expires September 4, 2020 [Page 1]
Internet-Draft Network Service Header TLVs March 2020
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions used in this document . . . . . . . . . . . . . . 2
2.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
2.2. Requirements Language . . . . . . . . . . . . . . . . . . 3
3. NSH Type 2 Format . . . . . . . . . . . . . . . . . . . . . . 3
4. NSH Type 2 TLVs . . . . . . . . . . . . . . . . . . . . . . . 4
4.1. Forwarding Context . . . . . . . . . . . . . . . . . . . 4
4.2. Tenant Identifier . . . . . . . . . . . . . . . . . . . . 5
4.3. Content Type . . . . . . . . . . . . . . . . . . . . . . 6
4.4. Ingress Network Information . . . . . . . . . . . . . . . 6
4.5. Flow ID . . . . . . . . . . . . . . . . . . . . . . . . . 6
4.6. Source and/or Destination Groups . . . . . . . . . . . . 7
4.7. Universal Resource Identifier . . . . . . . . . . . . . . 7
4.8. Policy Identifier (POLICY_ID) . . . . . . . . . . . . . . 8
5. Security Considerations . . . . . . . . . . . . . . . . . . . 8
6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 9
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 9
8.1. Normative References . . . . . . . . . . . . . . . . . . 10
8.2. Informative References . . . . . . . . . . . . . . . . . 10
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10
1. Introduction
Network Service Header (NSH) [RFC8300] is the Service Function
Chaining (SFC) encapsulation protocol used to create Service Function
Chains. As such, NSH provides two key elements:
1. Service Function Path identification
2. Metadata
[RFC8300] further defines two metadata formats (MD Types): 1 and 2.
MD Type 1 defines fixed length, 16 bytes-long metadata, whereas MD
Type 2 defines a variable-length TLV format for metadata. This draft
defines some common TLVs for use with NSH MD Type 2.
This draft does not address metadata usage, updating/chaining of
metadata or other SFP functions. Those topics are described in
[RFC8300].
2. Conventions used in this document
Wei, et al. Expires September 4, 2020 [Page 2]
Internet-Draft Network Service Header TLVs March 2020
2.1. Terminology
NSH: Network Service Header
MD Type: Metadata Format
CT: Context Type
TT: Tenant Type
URI: Universal Resource Identifier
SFC: Service Function Chaining
2.2. 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 BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
3. NSH Type 2 Format
A NSH is composed of a 4-byte Base Header, a 4-byte Service Path
Header and Context Headers. The Base Header identifies the MD-Type
in use:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Ver|O|C|R|R|R|R|R|R| Length | MD Type | Next Protocol |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: NSH Base Header
Please refer to NSH [RFC8300] for a detailed header description.
When the base header specifies MD Type = 0x2, zero or more Variable
Length Context Headers MAY be added, immediately following the
Service Path Header. Therefore, Length = 0x2 indicates that only the
Base Header followed by the Service Path Header is present. The
number, indicated in the Length field, of optional Variable Length
Context Headers MUST be of an integer indicating length in 4-bytes
words Figure 2 below depicts the format of the Context Header as
defined in Section 2.5.1 of [RFC8300].
Wei, et al. Expires September 4, 2020 [Page 3]
Internet-Draft Network Service Header TLVs March 2020
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Metadata Class | Type |U| Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Variable-Length Metadata |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: NSH TLV Format
where
Metadata Class (MD Class): Defines the scope of the Type field to
provide a hierarchical namespace.
Type - Indicates the explicit type of metadata being carried. The
value is one from the Network Service Header (NSH) TLV Type
registry (Section 7).
Unassigned bit: One unassigned bit is available for future use.
This bit MUST NOT be set, and it MUST be ignored on receipt.
Length: Indicates the length of the variable-length metadata, in
bytes. In case the metadata length is not an integer number of
4-byte words, the sender MUST add pad bytes immediately following
the last metadata byte to extend the metadata to an integer number
of 4-byte words. The receiver MUST round the Length field up to
the nearest 4-byte-word boundary, to locate and process the next
field in the packet. The receiver MUST access only those bytes in
the metadata indicated by the Length field (i.e., actual number of
bytes) and MUST ignore the remaining bytes up to the nearest 4-
byte-word boundary. The length may be 0 or greater.
A value of 0 denotes a Context Header without a Variable-Length
Metadata field.
4. NSH Type 2 TLVs
In [RFC8300] defined that Metadata Class 0x0000 as IETF Base NSH MD
Class. In this draft, metadata types are defined for the IETF Base
NSH MD Class.
4.1. Forwarding Context
This TLV carries a network-centric forwarding context, used for
segregation and forwarding scope. Forwarding context can take
several forms depending on the network environment. Commonly used
data includes VXLAN/VXLAN- GPE VNID, VRF identification or VLAN.
Wei, et al. Expires September 4, 2020 [Page 4]
Internet-Draft Network Service Header TLVs March 2020
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Metadata Class = 0x0000 | Type = 0x01 |U| Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| CT | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tenant ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3: Forwarding Context
where:
Context Type (CT) is four bits-long field that defines the length
and the interpretation of the Tenant ID field. This document
defines these CT values:
0x0 - 24 bits-long VXLAN/LISP virtual network identifier (VNI)
0x1 - 32 bits-long MPLS VPN label
0x2 - VLAN
4.2. Tenant Identifier
Tenant identification is often used for segregation within a multi-
tenant environment. Orchestration system-generated tenant IDs are an
example of such data.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Metadata Class = 0x0000 | Type = 0x02 |U| Length=12 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TT | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tenant ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tenant ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4: Tenant Identifier List
where:
Wei, et al. Expires September 4, 2020 [Page 5]
Internet-Draft Network Service Header TLVs March 2020
Tenant Type (TT) is four bits-long field that specifies the length
of the Tenant ID field. This document defines the following
values for TT:
* 0x0 - 32 bits-long Tenant ID
* 0x1 - 64 bits-long Tenant ID
4.3. Content Type
Provides explicit information about the content being carried, for
example, type of video or content value for billing purposes.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Metadata Class = 0x0000 | Type = 0x03 |U| Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Content Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 5: Content Type
4.4. Ingress Network Information
This data identifies the ingress network node, and, if required,
ingress interface.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Metadata Class = 0x0000 | Type = 0x04 |U| Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Node ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Source Interface/Port |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 6: Ingress Network Information
4.5. Flow ID
Flow ID provides a representation of the flow. Akin, but not
identical to the usage described in [RFC6437].
Wei, et al. Expires September 4, 2020 [Page 6]
Internet-Draft Network Service Header TLVs March 2020
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Metadata Class = 0x0000 | Type = 0x05 |U| Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flow ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 7: Flow ID
4.6. Source and/or Destination Groups
Intent-based systems can use this data to express the logical
grouping of source and/or destination objects. [GROUPBASEDPOLICY]
and [GROUPPOLICY] provide examples of such a system.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Metadata Class = 0x0000 | Type = 0x06 |U| Length=12 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| GT | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Source Group |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Dest Group |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 8: End Point Group
where:
Group Type (GT) is four bits-long field that specifies the the
interpretation of Source Group and/or Destination Group fields.
This document defines the following values for GT:
* 0x1 - Group Based Policy (GBP) end point group (EPG)
4.7. Universal Resource Identifier
Wei, et al. Expires September 4, 2020 [Page 7]
Internet-Draft Network Service Header TLVs March 2020
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Metadata Class = 0x0000 | Type = 0x07 |U| Length=var |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| UT | URI |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ URI ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 9: Universal Resource Identifier
where
URI (Universal Resource Identifier) Type is four bits-long field
that specifies the format of the URI field. This document defines
the following values for the URI Type field:
* 0x1: URI in standard string format as defined in [RFC3986].
* 0x2: URI represented in a compacted hash format.
4.8. Policy Identifier (POLICY_ID)
The policy is often referred by a system-generated identifier which
is then used by the devices to lookup the content of the policy
locally. For example, this identifier could be an index to an array,
a lookup key, a database Id. The identifier allows enforcement
agents or services to lookup up the content of their part of the
policy quite efficiently.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Metadata Class = 0x0000 | Type = 0x08 |U| Length=var |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| POLICY_ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ POLICY_ID ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 10: POLICY_ID
5. Security Considerations
[RFC8300] describes the requisite security considerations for
protecting NSH metadata.
Wei, et al. Expires September 4, 2020 [Page 8]
Internet-Draft Network Service Header TLVs March 2020
6. Acknowledgments
The authors would like to thank Paul Quinn for contributing to the
draft and thank Behcet Sarikaya, Dirk von Hugo and Mohamed Boucadair
for their work regarding usage of subscriber and host information
TLVs.
7. IANA Considerations
IANA is requested to create a new "Network Service Header (NSH) TLV
Type" registry according to Table 1.
+-----------+--------------+-------------------------+
| Value | Description | Reference |
+-----------+--------------+-------------------------+
| 0 | Reserved | This document |
| 1- 127 | Unassigned | IETF Review |
| 128 - 239 | Unassigned | First Come First Served |
| 240 - 249 | Experimental | This document |
| 250 - 254 | Private Use | This document |
| 255 | Reserved | This document |
+-----------+--------------+-------------------------+
Table 1: Network Service Header (NSH) TLV Type
This document defines the following new values (Table 2) in the
Network Service Header (NSH) TLV Type registry:
+-------+----------------------------------+---------------+
| Value | Description | Reference |
+-------+----------------------------------+---------------+
| 1 | Forwarding Context | This document |
| 2 | Tenant Identifier | This document |
| 3 | Content Type | This document |
| 4 | Ingress Network Information | This document |
| 5 | Flow ID | This document |
| 6 | Source and/or Destination Groups | This document |
| 7 | Universal Resource Identifier | This document |
| 8 | Policy Identifier | This document |
+-------+----------------------------------+---------------+
Table 2: Type Values
8. References
Wei, et al. Expires September 4, 2020 [Page 9]
Internet-Draft Network Service Header TLVs March 2020
8.1. 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>.
[RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Resource Identifier (URI): Generic Syntax", STD 66,
RFC 3986, DOI 10.17487/RFC3986, January 2005,
<https://www.rfc-editor.org/info/rfc3986>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8300] Quinn, P., Ed., Elzur, U., Ed., and C. Pignataro, Ed.,
"Network Service Header (NSH)", RFC 8300,
DOI 10.17487/RFC8300, January 2018,
<https://www.rfc-editor.org/info/rfc8300>.
8.2. Informative References
[GROUPBASEDPOLICY]
OpenStack, "Group Based Policy", 2014.
[GROUPPOLICY]
OpenDaylight, "Group Policy", 2014.
[RFC6437] Amante, S., Carpenter, B., Jiang, S., and J. Rajahalme,
"IPv6 Flow Label Specification", RFC 6437,
DOI 10.17487/RFC6437, November 2011,
<https://www.rfc-editor.org/info/rfc6437>.
Authors' Addresses
Yuehua (Corona) Wei (editor)
ZTE Corporation
No.50, Software Avenue
Nanjing 210012
China
Email: wei.yuehua@zte.com.cn
Wei, et al. Expires September 4, 2020 [Page 10]
Internet-Draft Network Service Header TLVs March 2020
Uri Elzur
Intel
Email: uri.elzur@intel.com
Sumandra Majee
Caber systems inc
Email: Sum.majee@gmail.com
Wei, et al. Expires September 4, 2020 [Page 11]