Network Working Group P. Quinn
Internet-Draft Cisco Systems, Inc.
Intended status: Standards Track U. Elzur
Expires: April 21, 2018 Intel
S. Majee
F5
October 18, 2017
Network Service Header TLVs
draft-quinn-sfc-nsh-tlv-04.txt
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
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This Internet-Draft will expire on April 21, 2018.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. NSH Type 2 Format . . . . . . . . . . . . . . . . . . . . . . 2
3. NSH Type 2 TLVs . . . . . . . . . . . . . . . . . . . . . . . 3
4. Security Considerations . . . . . . . . . . . . . . . . . . . 7
5. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 7
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 7
7.1. Normative References . . . . . . . . . . . . . . . . . . 7
7.2. Informative References . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8
1. Introduction
Network Service Header [NSH] is the SFC encapsulation protocol used
to create Service Function Chains. As such, NSH provides two key
elements:
1. Service Function Path identification
2. Metadata
NSH further defines two metadata formats (MD Types): 1 and 2. MD
Type 1 defines fixed length, 16 byte 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 NSH.
2. 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 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 [NSH] for a detailed header description.
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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 are 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 3 below depicts the format the context header.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Class |C| Type |R|R|R| Len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Variable Metadata |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: NSH TLV Format
3. NSH Type 2 TLVs
As per NSH, TLV Class 0-7 are reserved for standards use. In this
draft we use TLV Class 0 for the following Types:
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Class = 0x0 |C| Type |R|R|R| Len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Variable Metadata |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3: NSH TLV Class=0x0
1. Forwarding Context
This TLV carries 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.
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Class = 0x0 |C| Type=0x1 |R|R|R| L=0x2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|CT (4)| Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tentant ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Context Type (CT), 4 bits:
0x0: 24 bit VXLAN/LISP virtual network identifier (VNI)
0x1: 32 bit MPLS VPN label
0x2: VLAN
Figure 4: Forwarding Context
2. Tenant
Tenant identification is often used for segregation within a
multi-tenant environment. Orchestration system generated tenant
IDs are an example of such data.
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Class = 0x0 |C| Type=0x4 |R|R|R| L=0x3 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|TT (4)| Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tenant ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tenant ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Tenant Type (TT), 4 bits:
0x0: 32 bit
0x1: 64 bit
Figure 5: Tenant Identifier
3. Content Type
Provides explicit information about the content being carried,
for example, type of video or content value for billing purposes
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Class = 0x0 |C| Type=0x6 |R|R|R| L=0x1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Content Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 6: Content Type
4. Ingress Network Information
This data identifies ingress network node, and, if required,
ingress interface.
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Class = 0x0 |C| Type=0x7 |R|R|R| L=0x2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Node ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Source Interface/Port |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 7: Ingress Network Info
5. Flow ID
Flow ID provides a representation of flow. Akin, but not
identical to the usage described in [RFC6437]
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Class = 0x0 |C| Type=0x8 |R|R|R| L=0x1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flow ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 8: Flow ID
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.
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Class = 0x0 |C| Type=0x9 |R|R|R| L=0x3 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|GT(4) | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Source Group |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Dest Group |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Group type (4):
0x1: Group Based Policy (GBP) end point group (EPG)
Figure 9: End Point Group
7. Universal Resource Identifier (URI)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Class = 0x0 |C| Type=0xA |R|R|R| L=var |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|UT(4) | URI |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ URI ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
URI type (4):
0x1: URI in standard string format as defined in RFC 3986
0x2: URI represented in a compacted hash format
Figure 10: URI
8. Policy Identifier (POLICY_ID)
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.
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Class = 0x0 |C| Type=0xB |R|R|R| L=0x2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| POLICY_ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ POLICY_ID ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 11: POLICY_ID
4. Security Considerations
NSH describes the requisite security considerations for protecting
NSH metadata.
5. Acknowledgments
The authors would like to thank Behcet Sarikaya, Dirk von Hugo and
Mohamed Boucadair for their work regarding usage of subscriber and
host information TLVs.
6. IANA Considerations
IANA is requested to create a new "Network Service Header (NSH) TLV
Type" registry. TLV types 0-127 are specified in this document. New
values are assigned via Standards Action [RFC5226].
7. References
7.1. Normative References
[NSH] Quinn, P., Ed. and U. Elzur, Ed., "Network Service
Header", 2016, <https://datatracker.ietf.org/doc/draft-
ietf-sfc-nsh/>.
7.2. Informative References
[GROUPBASEDPOLICY]
OpenStack, "Group Based Policy", 2014,
<https://wiki.openstack.org/wiki/GroupBasedPolicy>.
[GROUPPOLICY]
OpenDaylight, "Group Policy", 2014,
<https://wiki.opendaylight.org/view/Group_Policy:Main>.
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[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", RFC 5226,
DOI 10.17487/RFC5226, May 2008, <https://www.rfc-
editor.org/info/rfc5226>.
[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
Paul Quinn
Cisco Systems, Inc.
Email: paulq@cisco.com
Uri Elzur
Intel
Email: uri.elzur@intel.com
Sumandra Majee
F5
Email: S.Majee@F5.com
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