draft-ietf-sfc-nsh-18.txt   draft-ietf-sfc-nsh-19.txt 
Service Function Chaining P. Quinn, Ed. Service Function Chaining P. Quinn, Ed.
Internet-Draft Cisco Internet-Draft Cisco
Intended status: Standards Track U. Elzur, Ed. Intended status: Standards Track U. Elzur, Ed.
Expires: January 26, 2018 Intel Expires: February 13, 2018 Intel
C. Pignataro, Ed. C. Pignataro, Ed.
Cisco Cisco
July 25, 2017 August 12, 2017
Network Service Header (NSH) Network Service Header (NSH)
draft-ietf-sfc-nsh-18 draft-ietf-sfc-nsh-19
Abstract Abstract
This document describes a Network Service Header (NSH) inserted onto This document describes a Network Service Header (NSH) inserted onto
packets or frames to realize service function paths. NSH also packets or frames to realize service function paths. NSH also
provides a mechanism for metadata exchange along the instantiated provides a mechanism for metadata exchange along the instantiated
service paths. NSH is the SFC encapsulation required to support the service paths. NSH is the SFC encapsulation required to support the
Service Function Chaining (SFC) architecture (defined in RFC7665). Service Function Chaining (SFC) architecture (defined in RFC7665).
Status of This Memo Status of This Memo
skipping to change at page 1, line 37 skipping to change at page 1, line 37
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This Internet-Draft will expire on January 26, 2018. This Internet-Draft will expire on February 13, 2018.
Copyright Notice Copyright Notice
Copyright (c) 2017 IETF Trust and the persons identified as the Copyright (c) 2017 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3 1.1. Requirements Language . . . . . . . . . . . . . . . . . . 4
1.2. Definition of Terms . . . . . . . . . . . . . . . . . . . 4 1.2. Definition of Terms . . . . . . . . . . . . . . . . . . . 4
1.3. Problem Space . . . . . . . . . . . . . . . . . . . . . . 4 1.3. Problem Space . . . . . . . . . . . . . . . . . . . . . . 5
1.4. NSH-based Service Chaining . . . . . . . . . . . . . . . 5 1.4. NSH-based Service Chaining . . . . . . . . . . . . . . . 5
2. Network Service Header . . . . . . . . . . . . . . . . . . . 5 2. Network Service Header . . . . . . . . . . . . . . . . . . . 6
2.1. Network Service Header Format . . . . . . . . . . . . . . 6 2.1. Network Service Header Format . . . . . . . . . . . . . . 6
2.2. NSH Base Header . . . . . . . . . . . . . . . . . . . . . 6 2.2. NSH Base Header . . . . . . . . . . . . . . . . . . . . . 7
2.3. Service Path Header . . . . . . . . . . . . . . . . . . . 9 2.3. Service Path Header . . . . . . . . . . . . . . . . . . . 9
2.4. NSH MD Type 1 . . . . . . . . . . . . . . . . . . . . . . 10 2.4. NSH MD Type 1 . . . . . . . . . . . . . . . . . . . . . . 10
2.5. NSH MD Type 2 . . . . . . . . . . . . . . . . . . . . . . 11 2.5. NSH MD Type 2 . . . . . . . . . . . . . . . . . . . . . . 11
2.5.1. Optional Variable Length Metadata . . . . . . . . . . 11 2.5.1. Optional Variable Length Metadata . . . . . . . . . . 12
3. NSH Actions . . . . . . . . . . . . . . . . . . . . . . . . . 13 3. NSH Actions . . . . . . . . . . . . . . . . . . . . . . . . . 13
4. NSH Transport Encapsulation . . . . . . . . . . . . . . . . . 14 4. NSH Transport Encapsulation . . . . . . . . . . . . . . . . . 15
5. Fragmentation Considerations . . . . . . . . . . . . . . . . 15 5. Fragmentation Considerations . . . . . . . . . . . . . . . . 15
6. Service Path Forwarding with NSH . . . . . . . . . . . . . . 15 6. Service Path Forwarding with NSH . . . . . . . . . . . . . . 16
6.1. SFFs and Overlay Selection . . . . . . . . . . . . . . . 15 6.1. SFFs and Overlay Selection . . . . . . . . . . . . . . . 16
6.2. Mapping NSH to Network Transport . . . . . . . . . . . . 18 6.2. Mapping NSH to Network Transport . . . . . . . . . . . . 19
6.3. Service Plane Visibility . . . . . . . . . . . . . . . . 19 6.3. Service Plane Visibility . . . . . . . . . . . . . . . . 20
6.4. Service Graphs . . . . . . . . . . . . . . . . . . . . . 19 6.4. Service Graphs . . . . . . . . . . . . . . . . . . . . . 20
7. Policy Enforcement with NSH . . . . . . . . . . . . . . . . . 19 7. Policy Enforcement with NSH . . . . . . . . . . . . . . . . . 20
7.1. NSH Metadata and Policy Enforcement . . . . . . . . . . . 19 7.1. NSH Metadata and Policy Enforcement . . . . . . . . . . . 20
7.2. Updating/Augmenting Metadata . . . . . . . . . . . . . . 21 7.2. Updating/Augmenting Metadata . . . . . . . . . . . . . . 22
7.3. Service Path Identifier and Metadata . . . . . . . . . . 23 7.3. Service Path Identifier and Metadata . . . . . . . . . . 24
8. Security Considerations . . . . . . . . . . . . . . . . . . . 23 8. Security Considerations . . . . . . . . . . . . . . . . . . . 24
9. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 24 9. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 26
10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 26 10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 28
11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 27 11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 28
11.1. NSH EtherType . . . . . . . . . . . . . . . . . . . . . 27 11.1. NSH EtherType . . . . . . . . . . . . . . . . . . . . . 28
11.2. Network Service Header (NSH) Parameters . . . . . . . . 27 11.2. Network Service Header (NSH) Parameters . . . . . . . . 28
11.2.1. NSH Base Header Unassigned Bits . . . . . . . . . . 27 11.2.1. NSH Base Header Bits . . . . . . . . . . . . . . . . 29
11.2.2. NSH Version . . . . . . . . . . . . . . . . . . . . 27 11.2.2. NSH Version . . . . . . . . . . . . . . . . . . . . 29
11.2.3. MD Type Registry . . . . . . . . . . . . . . . . . . 28 11.2.3. MD Type Registry . . . . . . . . . . . . . . . . . . 29
11.2.4. MD Class Registry . . . . . . . . . . . . . . . . . 28 11.2.4. MD Class Registry . . . . . . . . . . . . . . . . . 29
11.2.5. NSH Base Header Next Protocol . . . . . . . . . . . 29 11.2.5. NSH Base Header Next Protocol . . . . . . . . . . . 30
11.2.6. New IETF assigned MD Type Registry . . . . . . . . . 29 11.2.6. New IETF Assigned Optional Variable Length Metadata
12. References . . . . . . . . . . . . . . . . . . . . . . . . . 30 Type Registry . . . . . . . . . . . . . . . . . . . 31
12.1. Normative References . . . . . . . . . . . . . . . . . . 30 12. References . . . . . . . . . . . . . . . . . . . . . . . . . 31
12.2. Informative References . . . . . . . . . . . . . . . . . 30 12.1. Normative References . . . . . . . . . . . . . . . . . . 31
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 31 12.2. Informative References . . . . . . . . . . . . . . . . . 32
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 33
1. Introduction 1. Introduction
Service functions are widely deployed and essential in many networks. Service functions are widely deployed and essential in many networks.
These service functions provide a range of features such as security, These service functions provide a range of features such as security,
WAN acceleration, and server load balancing. Service functions may WAN acceleration, and server load balancing. Service functions may
be instantiated at different points in the network infrastructure be instantiated at different points in the network infrastructure
such as the wide area network, data center, campus, and so forth. such as the wide area network, data center, campus, and so forth.
Prior to development of the SFC architecture [RFC7665] and the Prior to development of the SFC architecture [RFC7665] and the
protocol specified in this document, current service function protocol specified in this document, current service function
deployment models have been relatively static, and bound to topology deployment models have been relatively static, and bound to topology
for insertion and policy selection. Furthermore, they do not adapt for insertion and policy selection. Furthermore, they do not adapt
well to elastic service environments enabled by virtualization. well to elastic service environments enabled by virtualization.
New data center network and cloud architectures require more flexible New data center network and cloud architectures require more flexible
service function deployment models. Additionally, the transition to service function deployment models. Additionally, the transition to
virtual platforms requires an agile service insertion model that virtual platforms demands an agile service insertion model that
supports dynamic and elastic service delivery; the movement of supports dynamic and elastic service delivery. Specifically, the
service functions and application workloads in the network and the following functions are necessary:
ability to easily bind service policy to granular information such as
per-subscriber state and steer traffic to the requisite service
function(s) are necessary.
Network Service Header (NSH) defines a new service plane protocol The movement of service functions and application workloads in the
specifically for the creation of dynamic service chains and is network.
composed of the following elements:
The ability to easily bind service policy to granular information,
such as per-subscriber state.
The capability to steer traffic to the requisite service
function(s).
The Network Service Header (NSH) specification defines a new protocol
for the creation of dynamic service chains, operating at the service
plane. NSH is composed of the following elements:
1. Service Function Path identification. 1. Service Function Path identification.
2. Indication of location within a Service Function Path. 2. Indication of location within a Service Function Path.
3. Optional, per packet metadata (fixed length or variable). 3. Optional, per packet metadata (fixed length or variable).
NSH is designed to be easy to implement across a range of devices, NSH is designed to be easy to implement across a range of devices,
both physical and virtual, including hardware platforms. both physical and virtual, including hardware platforms.
The intended scope of NSH is for use within a single provider's
operational domain. This deployment scope is deliberatedly
constrained, as explained also in [RFC7665], and limited to a single
network administrative domain. In this context, a "domain" is a set
of network entities within a single administration. For example, a
network administrative domain can include a single data center, a
campus physical network, or an overlay domain using virtual
connetions and tunnels. A corollary is that a network administrative
domain has a well defined perimeter.
An NSH-aware control plane is outside the scope of this document. An NSH-aware control plane is outside the scope of this document.
[RFC7665] provides an overview of a service chaining architecture [RFC7665] provides an overview of a service chaining architecture
that clearly defines the roles of the various elements and the scope that clearly defines the roles of the various elements and the scope
of a service function chaining encapsulation. NSH is the SFC of a service function chaining encapsulation. NSH is the SFC
encapsulation referenced in [RFC7665]. encapsulation referenced in [RFC7665].
1.1. Requirements Language 1.1. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
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Byte: All references to "bytes" in this document refer to 8-bit Byte: All references to "bytes" in this document refer to 8-bit
bytes, or octets. bytes, or octets.
Classification: Defined in [RFC7665]. Classification: Defined in [RFC7665].
Classifier: Defined in [RFC7665]. Classifier: Defined in [RFC7665].
Metadata: Defined in [RFC7665]. Metadata: Defined in [RFC7665].
Network Locator: dataplane address, typically IPv4 or IPv6, used to Network Locator: Dataplane address, typically IPv4 or IPv6, used to
send and receive network traffic. send and receive network traffic.
Network Node/Element: Device that forwards packets or frames based Network Node/Element: Device that forwards packets or frames based
on an outer header (i.e., transport) information. on an outer header (i.e., encapsulation) information.
Network Overlay: Logical network built on top of existing network Network Overlay: Logical network built on top of existing network
(the underlay). Packets are encapsulated or tunneled to create (the underlay). Packets are encapsulated or tunneled to create
the overlay network topology. the overlay network topology.
NSH-aware SFC-encapsulation-aware, or SFC-aware [RFC7665]. NSH-aware: NSH-aware means SFC-encapsulation-aware, with NSH as the
SFC encapsulation. This specification uses NSH-aware as a more
specific term from the more generic term SFC-aware [RFC7665].
Service Classifier: Logical entity providing classification Service Classifier: Logical entity providing classification
function. Since they are logical, classifiers may be co-resident function. Since they are logical, classifiers may be co-resident
with SFC elements such as SFs or SFFs. Service classifiers with SFC elements such as SFs or SFFs. Service classifiers
perform classification and impose NSH. The initial classifier perform classification and impose NSH. The initial classifier
imposes the initial NSH and sends the NSH packet to the first SFF imposes the initial NSH and sends the NSH packet to the first SFF
in the path. Non-initial (i.e. subsequent) classification can in the path. Non-initial (i.e., subsequent) classification can
occur as needed and can alter, or create a new service path. occur as needed and can alter, or create a new service path.
Service Function (SF): Defined in [RFC7665]. Service Function (SF): Defined in [RFC7665].
Service Function Chain (SFC): Defined in [RFC7665]. Service Function Chain (SFC): Defined in [RFC7665].
Service Function Forwarder (SFF): Defined in [RFC7665]. Service Function Forwarder (SFF): Defined in [RFC7665].
Service Function Path (SFP): Defined in [RFC7665]. Service Function Path (SFP): Defined in [RFC7665].
Service Plane: The collection of SFFs and associated SFs creates a
service-plane overlay in which all SFs reside [RFC7665].
SFC Proxy: Defined in [RFC7665]. SFC Proxy: Defined in [RFC7665].
1.3. Problem Space 1.3. Problem Space
NSH addresses several limitations associated with service function NSH addresses several limitations associated with service function
deployments. [RFC7498] provides a comprehensive review of those deployments. [RFC7498] provides a comprehensive review of those
issues. issues.
1.4. NSH-based Service Chaining 1.4. NSH-based Service Chaining
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Section 3.3. Examples of metadata include classification Section 3.3. Examples of metadata include classification
information used for policy enforcement and network context for information used for policy enforcement and network context for
forwarding post service delivery. Sharing the metadata allows forwarding post service delivery. Sharing the metadata allows
service functions to share initial and intermediate service functions to share initial and intermediate
classification results with downstream service functions saving classification results with downstream service functions saving
re-classification, where enough information was enclosed. re-classification, where enough information was enclosed.
4. NSH offers a common and standards-based header for service 4. NSH offers a common and standards-based header for service
chaining to all network and service nodes. chaining to all network and service nodes.
5. Transport Agnostic: NSH is transport-independent. An appropriate 5. Transport Agnostic: NSH is encapsulation-independent, meaning it
(for a given deployment) network transport protocol can be used can be transported by a variety of protocols. An appropriate
to transport NSH-encapsulated traffic. This transport may form (for a given deployment) encapsulation protocol can be used to
an overlay network and if an existing overlay topology provides carry NSH-encapsulated traffic. This transport may form an
the required service path connectivity, that existing overlay may overlay network and if an existing overlay topology provides the
be used. required service path connectivity, that existing overlay may be
used.
2. Network Service Header 2. Network Service Header
NSH contains service path information and optionally metadata that NSH contains service path information and optionally metadata that
are added to a packet or frame and used to create a service plane. are added to a packet or frame and used to create a service plane.
An outer transport header is imposed, on NSH and the original packet/ An outer transport header is imposed, on NSH and the original packet/
frame, for network forwarding. frame, for network forwarding.
A Service Classifier adds NSH. NSH is removed by the last SFF in the A Service Classifier adds NSH. NSH is removed by the last SFF in the
service chain or by an SF that consumes the packet. service chain or by an SF that consumes the packet.
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Service Path Header | | Service Path Header |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
~ Context Header(s) ~ ~ Context Header(s) ~
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: Network Service Header Figure 1: Network Service Header
Base header: provides information about the service header and the Base header: Provides information about the service header and the
payload protocol. payload protocol.
Service Path Header: provides path identification and location within Service Path Header: Provides path identification and location within
a service path. a service path.
Context header: carries metadata (i.e., context data) along a service Context header: Carries metadata (i.e., context data) along a service
path. path.
2.2. NSH Base Header 2.2. NSH Base Header
Figure 2 depicts the NSH base header: Figure 2 depicts the NSH base header:
0 1 2 3 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 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|U| TTL | Length |U|U|U|U|MD Type| Next Protocol | |Ver|O|U| TTL | Length |U|U|U|U|MD Type| Next Protocol |
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procedures may be acceptable for a subset of OAM functions, but can procedures may be acceptable for a subset of OAM functions, but can
result in unexpected outcomes for others, thus it is recommended to result in unexpected outcomes for others, thus it is recommended to
analyze the impact of forwarding an OAM packet for all OAM functions analyze the impact of forwarding an OAM packet for all OAM functions
prior to enabling this behavior. The configurable parameter MUST be prior to enabling this behavior. The configurable parameter MUST be
disabled by default. disabled by default.
TTL: Indicates the maximum SFF hops for an SFP. This field is used TTL: Indicates the maximum SFF hops for an SFP. This field is used
for service plane loop detection. The initial TTL value SHOULD be for service plane loop detection. The initial TTL value SHOULD be
configurable via the control plane; the configured initial value can configurable via the control plane; the configured initial value can
be specific to one or more SFPs. If no initial value is explicitly be specific to one or more SFPs. If no initial value is explicitly
provided, the default initial TTL value 63 MUST be used. Each SFF provided, the default initial TTL value of 63 MUST be used. Each SFF
involved in forwarding an NSH packet MUST decrement the TTL value by involved in forwarding an NSH packet MUST decrement the TTL value by
1 prior to NSH forwarding lookup. Decrementing by 1 from an incoming 1 prior to NSH forwarding lookup. Decrementing by 1 from an incoming
value of 0 shall result in a TTL value of 63. The packet MUST NOT be value of 0 shall result in a TTL value of 63. The packet MUST NOT be
forwarded if TTL is, after decrement, 0. forwarded if TTL is, after decrement, 0.
All other flag fields are unassigned and available for future use, All other flag fields, marked U, are unassigned and available for
see Section 11.2.1. Unassigned bits MUST be set to zero upon future use, see Section 11.2.1. Unassigned bits MUST be set to zero
origination and MUST be preserved unmodified by other NSH supporting upon origination, and MUST be ignored and preserved unmodified by
elements. Elements which do not understand the meaning of any of other NSH supporting elements. Elements which do not understand the
these bits MUST NOT modify their actions based on those unknown bits. meaning of any of these bits MUST NOT modify their actions based on
those unknown bits.
Length: The total length, in 4-byte words, of NSH including the Base Length: The total length, in 4-byte words, of NSH including the Base
Header, the Service Path Header, the Fixed Length Context Header or Header, the Service Path Header, the Fixed Length Context Header or
Variable Length Context Header(s). The length MUST be of value 0x6 Variable Length Context Header(s). The length MUST be 0x6 for MD
for MD Type equal to 0x1, and MUST be of value 0x2 or greater for MD Type equal to 0x1, and MUST be 0x2 or greater for MD Type equal to
Type equal to 0x2. The length of the NSH header MUST be an integer 0x2. The length of the NSH header MUST be an integer multiple of 4
multiple of 4 bytes, thus variable length metadata is always padded bytes, thus variable length metadata is always padded out to a
out to a multiple of 4 bytes. multiple of 4 bytes.
MD Type: indicates the format of NSH beyond the mandatory Base Header MD Type: Indicates the format of NSH beyond the mandatory Base Header
and the Service Path Header. MD Type defines the format of the and the Service Path Header. MD Type defines the format of the
metadata being carried. Please see the IANA Considerations metadata being carried. Please see the IANA Considerations
Section 11.2.3. Section 11.2.3.
This document specifies the following four MD Type values: This document specifies the following four MD Type values:
0x0 - this is a reserved value. Implementations SHOULD silently 0x0 - This is a reserved value. Implementations SHOULD silently
discard packets with MD Type 0x0. discard packets with MD Type 0x0.
0x1 - which indicates that the format of the header includes a fixed 0x1 - This indicates that the format of the header includes a fixed
length Context Header (see Figure 4 below). length Context Header (see Figure 4 below).
0x2 - which does not mandate any headers beyond the Base Header and 0x2 - This does not mandate any headers beyond the Base Header and
Service Path Header, but may contain optional variable length Context Service Path Header, but may contain optional variable length Context
Header(s). The semantics of the variable length Context Header(s) Header(s). The semantics of the variable length Context Header(s)
are not defined in this document. The format of the optional are not defined in this document. The format of the optional
variable length Context Headers is provided in Section 2.5.1. variable length Context Headers is provided in Section 2.5.1.
0xF - this value is reserved for experimentation and testing, as per 0xF - This value is reserved for experimentation and testing, as per
[RFC3692]. Implementations not explicitly configured to be part of [RFC3692]. Implementations not explicitly configured to be part of
an experiment SHOULD silently discard packets with MD Type 0xF. an experiment SHOULD silently discard packets with MD Type 0xF.
The format of the Base Header and the Service Path Header is The format of the Base Header and the Service Path Header is
invariant, and not affected by MD Type. invariant, and not affected by MD Type.
NSH implementations MUST support MD type = 0x1 and MD Type = 0x2 NSH MD Type 1 and MD Type 2 are described in detail in Sections 2.4
(where the length is of value 0x2). NSH implementations SHOULD and 2.5, respectively. NSH implementations MUST support MD types 0x1
support MD Type 0x2 with length > 0x2. There exists, however, a and 0x2 (where the length is 0x2). NSH implementations SHOULD
middle ground, wherein a device will support MD Type 0x1 (as per the support MD Type 0x2 with length greater than 0x2. There exists,
MUST) metadata, yet be deployed in a network with MD Type 0x2 however, a middle ground, wherein a device will support MD Type 0x1
metadata packets. In that case, the MD Type 0x1 node, MUST utilize (as per the MUST) metadata, yet be deployed in a network with MD Type
the base header length field to determine the original payload offset 0x2 metadata packets. In that case, the MD Type 0x1 node, MUST
if it requires access to the original packet/frame. This utilize the base header length field to determine the original
specification does not disallow the MD Type value from changing along payload offset if it requires access to the original packet/frame.
an SFP; however, the specification of the necessary mechanism to This specification does not disallow the MD Type value from changing
allow the MD Type to change along an SFP are outside the scope of along an SFP; however, the specification of the necessary mechanism
to allow the MD Type to change along an SFP are outside the scope of
this document, and would need to be defined for that functionality to this document, and would need to be defined for that functionality to
be available. Packets with MD Type values not supported by an be available. Packets with MD Type values not supported by an
implementation MUST be silently dropped. implementation MUST be silently dropped.
Next Protocol: indicates the protocol type of the encapsulated data. Next Protocol: indicates the protocol type of the encapsulated data.
NSH does not alter the inner payload, and the semantics on the inner NSH does not alter the inner payload, and the semantics on the inner
protocol remain unchanged due to NSH service function chaining. protocol remain unchanged due to NSH service function chaining.
Please see the IANA Considerations section below, Section 11.2.5. Please see the IANA Considerations section below, Section 11.2.5.
This document defines the following Next Protocol values: This document defines the following Next Protocol values:
0x0: Unassigned
0x1: IPv4 0x1: IPv4
0x2: IPv6 0x2: IPv6
0x3: Ethernet 0x3: Ethernet
0x4: NSH 0x4: NSH
0x5: MPLS 0x5: MPLS
0xFE: Experiment 1 0xFE: Experiment 1
0xFF: Experiment 2 0xFF: Experiment 2
Packets with Next Protocol values not supported SHOULD be silently Packets with Next Protocol values not supported SHOULD be silently
dropped by default, although an implementation MAY provide a dropped by default, although an implementation MAY provide a
skipping to change at page 9, line 40 skipping to change at page 10, line 18
| Service Path Identifier (SPI) | Service Index | | Service Path Identifier (SPI) | Service Index |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Service Path Identifier (SPI): 24 bits Service Path Identifier (SPI): 24 bits
Service Index (SI): 8 bits Service Index (SI): 8 bits
Figure 3: NSH Service Path Header Figure 3: NSH Service Path Header
The meaning of these fields is as follows: The meaning of these fields is as follows:
Service Path Identifier (SPI): identifies a service path. Service Path Identifier (SPI): Identifies a service path.
Participating nodes MUST use this identifier for Service Function Participating nodes MUST use this identifier for Service Function
Path selection. The initial classifier MUST set the appropriate SPI Path selection. The initial classifier MUST set the appropriate SPI
for a given classification result. for a given classification result.
Service Index (SI): provides location within the SFP. The initial Service Index (SI): Provides location within the SFP. The initial
classifier for a given SFP SHOULD set the SI to 255, however the classifier for a given SFP SHOULD set the SI to 255, however the
control plane MAY configure the initial value of SI as appropriate control plane MAY configure the initial value of SI as appropriate
(i.e., taking into account the length of the service function path). (i.e., taking into account the length of the service function path).
Service Index MUST be decremented by a value of 1 by Service The Service Index MUST be decremented by a value of 1 by Service
Functions or by SFC Proxy nodes after performing required services Functions or by SFC Proxy nodes after performing required services
and the new decremented SI value MUST be used in the egress NSH and the new decremented SI value MUST be used in the egress packet's
packet. The initial Classifier MUST send the packet to the first SFF NSH. The initial Classifier MUST send the packet to the first SFF in
in the identified SFP for forwarding along an SFP. If re- the identified SFP for forwarding along an SFP. If re-classification
classification occurs, and that re-classification results in a new occurs, and that re-classification results in a new SPI, the
SPI, the (re)classifier is, in effect, the initial classifier for the (re)classifier is, in effect, the initial classifier for the
resultant SPI. resultant SPI.
The SI is used in conjunction with Service Path Identifier for The SI is used in conjunction the with Service Path Identifier for
Service Function Path Selection and for determining the next SFF/SF Service Function Path Selection and for determining the next SFF/SF
in the path. The SI is also valuable when troubleshooting/ reporting in the path. The SI is also valuable when troubleshooting or
service paths. Additionally, while the TTL field is the main reporting service paths. Additionally, while the TTL field is the
mechanism for service plane loop detection, the SI can also be used main mechanism for service plane loop detection, the SI can also be
for detecting service plane loops. used for detecting service plane loops.
2.4. NSH MD Type 1 2.4. NSH MD Type 1
When the Base Header specifies MD Type = 0x1, a Fixed Length Context When the Base Header specifies MD Type = 0x1, a Fixed Length Context
Header (16-bytes) MUST be present immediately following the Service Header (16-bytes) MUST be present immediately following the Service
Path Header, as per Figure 4. A Fixed Length Context Header that Path Header, as per Figure 4. The value of a Fixed Length Context
carries no metadata MUST be set to zero. Header that carries no metadata MUST be set to zero.
0 1 2 3 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 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|U| TTL | Length |U|U|U|U|MD Type| Next Protocol | |Ver|O|U| TTL | Length |U|U|U|U|MD Type| Next Protocol |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Service Path Identifier | Service Index | | Service Path Identifier | Service Index |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
| Fixed Length Context Header | | Fixed Length Context Header |
skipping to change at page 11, line 45 skipping to change at page 12, line 27
Figure 5: NSH MD Type=0x2 Figure 5: NSH MD Type=0x2
2.5.1. Optional Variable Length Metadata 2.5.1. Optional Variable Length Metadata
The format of the optional variable length Context Headers, is as The format of the optional variable length Context Headers, is as
depicted in Figure 6. depicted in Figure 6.
0 1 2 3 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 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| Len | | Metadata Class | Type |U| Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Variable Metadata | | Variable Metadata |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 6: Variable Context Headers Figure 6: Variable Context Headers
Metadata Class (MD Class): defines the scope of the 'Type' field to Metadata Class (MD Class): Defines the scope of the 'Type' field to
provide a hierarchical namespace. The IANA Considerations provide a hierarchical namespace. The IANA Considerations
Section 11.2.4 defines how the MD Class values can be allocated to Section 11.2.4 defines how the MD Class values can be allocated to
standards bodies, vendors, and others. standards bodies, vendors, and others.
Type: indicates the explicit type of metadata being carried and is Type: Indicates the explicit type of metadata being carried. The
the responsibility of the MD Class owner. definition of the Type is the responsibility of the MD Class owner.
Unassigned bit: one unassigned bit is available for future use. This Unassigned bit: One unassigned bit is available for future use. This
bit MUST be set to 0b. bit MUST NOT be set, and MUST be ignored on receipt.
Length: indicates the length of the variable metadata, in single byte Length: Indicates the length of the variable metadata, in bytes. In
words. In case the metadata length is not an integer number of case the metadata length is not an integer number of 4-byte words,
4-byte words, the sender MUST add pad bytes immediately following the the sender MUST add pad bytes immediately following the last metadata
last metadata byte to extend the metadata to an integer number of byte to extend the metadata to an integer number of 4-byte words.
4-byte words. The receiver MUST round up the length field to the The receiver MUST round up the length field to the nearest 4-byte
nearest 4-byte word boundary, to locate and process the next field in word boundary, to locate and process the next field in the packet.
the packet. The receiver MUST access only those bytes in the The receiver MUST access only those bytes in the metadata indicated
metadata indicated by the length field (i.e., actual number of single by the length field (i.e., actual number of bytes) and MUST ignore
byte words) and MUST ignore the remaining bytes up to the nearest the remaining bytes up to the nearest 4-byte word boundary. The
4-byte word boundary. The Length may be 0 or greater. Length may be 0 or greater.
A value of 0 denotes a Context Header without a Variable Metadata A value of 0 denotes a Context Header without a Variable Metadata
field. field.
This specification does not make any assumption about Context Headers This specification does not make any assumption about Context Headers
that are mandatory-to-implement or those that are mandatory-to- that are mandatory-to-implement or those that are mandatory-to-
process. These considerations are deployment-specific. However, the process. These considerations are deployment-specific. However, the
control plane is entitled to instruct SFC-aware SFs with the data control plane is entitled to instruct SFC-aware SFs with the data
structure of context header together with their scoping (see structure of context header together with its scoping (see
Section 3.3.3 of [I-D.ietf-sfc-control-plane]). Section 3.3.3 of [I-D.ietf-sfc-control-plane]).
Upon receipt of a packet that belong to a given SFP, if a mandatory- Upon receipt of a packet that belongs to a given SFP, if a mandatory-
to-process context header is missing in that packet, the SFC-aware SF to-process context header is missing in that packet, the SFC-aware SF
MUST NOT process the packet and MUST log at least once per the SPI MUST NOT process the packet and MUST log at least once per the SPI
for which a mandatory metadata is missing. for which the mandatory metadata is missing.
If multiple mandatory-to-process context headers are required for a If multiple mandatory-to-process context headers are required for a
given SFP, the control plane MAY instruct the SFC-aware SF with the given SFP, the control plane MAY instruct the SFC-aware SF with the
order to consume these Context Headers. If no instructions are order to consume these Context Headers. If no instructions are
provided, the SFC-aware SF MUST process these Context Headers in the provided, the SFC-aware SF MUST process these Context Headers in the
order their appear in an NSH packet. order they appear in an NSH packet.
If multiple instances of the same metadata are included in an NSH If multiple instances of the same metadata are included in an NSH
packet, but the definition of that context header does not allow for packet, but the definition of that context header does not allow for
it, the SFC-aware SF MUST process first instance and ignore it, the SFC-aware SF MUST process the first instance and ignore
subsequent instances. subsequent instances.
3. NSH Actions 3. NSH Actions
NSH-aware nodes are the only nodes that may alter the content of NSH NSH-aware nodes are the only nodes that may alter the content of NSH
headers. NSH-aware nodes include: service classifiers, SFF, SF and headers. NSH-aware nodes include: service classifiers, SFFs, SFs and
SFC proxies. These nodes have several possible NSH-related actions: SFC proxies. These nodes have several possible NSH-related actions:
1. Insert or remove NSH: These actions can occur at the start and 1. Insert or remove NSH: These actions can occur respectively at the
end respectively of a service path. Packets are classified, and start and end of a service path. Packets are classified, and if
if determined to require servicing, NSH will be imposed. A determined to require servicing, NSH will be imposed. A service
service classifier MUST insert NSH at the start of an SFP. An classifier MUST insert NSH at the start of an SFP. An imposed
imposed NSH MUST contain valid Base Header and Service Path NSH MUST contain both a valid Base Header and Service Path
Header. At the end of a service function path, an SFF, MUST be Header. At the end of a service function path, an SFF, MUST be
the last node operating on the service header and MUST remove NSH the last node operating on the service header and MUST remove NSH
before forwarding or delivering the un-encapsulated packet before forwarding or delivering the un-encapsulated packet.
Multiple logical classifiers may exist within a given service Multiple logical classifiers may exist within a given service
path. Non-initial classifiers may re-classify data and that re- path. Non-initial classifiers may re-classify data and that re-
classification MAY result in the selection a different Service classification MAY result in the selection of a different Service
Function Path. When the logical classifier performs re- Function Path. When the logical classifier performs re-
classification that results in a change of service path, it MUST classification that results in a change of service path, it MUST
remove the existing NSH and MUST impose a new NSH with the Base remove the existing NSH and MUST impose a new NSH with the Base
Header and Service Path Header reflecting the new service path Header and Service Path Header reflecting the new service path
information and set the initial SI. Metadata MAY be preserved in information and MUST set the initial SI. Metadata MAY be
the new NSH. preserved in the new NSH.
2. Select service path: The Service Path Header provides service 2. Select service path: The Service Path Header provides service
path information and is used by SFFs to determine correct service path information and is used by SFFs to determine correct service
path selection. SFFs MUST use the Service Path Header for path selection. SFFs MUST use the Service Path Header for
selecting the next SF or SFF in the service path. selecting the next SF or SFF in the service path.
3. Update NSH: SFs MUST decrement the service index by one. If an 3. Update NSH: SFs MUST decrement the service index by one. If an
SFF receives a packet with an SPI and SI that do not correspond SFF receives a packet with an SPI and SI that do not correspond
to a valid next hop in a valid Service Function Path, that packet to a valid next hop in a valid Service Function Path, that packet
MUST be dropped by the SFF. MUST be dropped by the SFF.
Classifiers MAY update Context Headers if new/updated context is Classifiers MAY update Context Headers if new/updated context is
available. available.
If an SFC proxy is in use (acting on behalf of a NSH unaware If an SFC proxy is in use (acting on behalf of a NSH unaware
service function for NSH actions), then the proxy MUST update service function for NSH actions), then the proxy MUST update
Service Index and MAY update contexts. When an SFC proxy Service Index and MAY update contexts. When an SFC proxy
receives an NSH-encapsulated packet, it MUST remove NSH before receives an NSH-encapsulated packet, it MUST remove NSH before
forwarding it to an NSH unaware SF. When the SFC Proxy receives forwarding it to an NSH unaware SF. When the SFC Proxy receives
a packet back from an NSH unaware SF, it MUST re-encapsulates it a packet back from an NSH unaware SF, it MUST re-encapsulate it
with the correct NSH, and MUST decrement the Service Index by with the correct NSH, and MUST decrement the Service Index by
one. one.
4. Service policy selection: Service Functions derive policy (i.e., 4. Service policy selection: Service Functions derive policy (i.e.,
service actions such as permit or deny) selection and enforcement service actions such as permit or deny) selection and enforcement
from NSH. Metadata shared in NSH can provide a range of service- from NSH. Metadata shared in NSH can provide a range of service-
relevant information such as traffic classification. relevant information such as traffic classification.
Figure 7 maps each of the four actions above to the components in the Figure 7 maps each of the four actions above to the components in the
SFC architecture that can perform it. SFC architecture that can perform it.
skipping to change at page 14, line 24 skipping to change at page 15, line 16
| | Insert |Forward| Update |Service | | | Insert |Forward| Update |Service |
| | or remove NSH |NSH | NSH |policy | | | or remove NSH |NSH | NSH |policy |
| | |Packets| |selection| | | |Packets| |selection|
| Component +-------+-------+ +----------------+ | | Component +-------+-------+ +----------------+ |
| | | | | Dec. |Update | | | | | | | Dec. |Update | |
| |Insert |Remove | |Service |Context| | | |Insert |Remove | |Service |Context| |
| | | | | Index |Header | | | | | | | Index |Header | |
+----------------+-------+-------+-------+--------+-------+---------+ +----------------+-------+-------+-------+--------+-------+---------+
| | + | + | | | + | | | | + | + | | | + | |
|Classifier | | | | | | | |Classifier | | | | | | |
+--------------- +-------+-------+-------+--------+-------+---------+ +----------------+-------+-------+-------+--------+-------+---------+
|Service Function| | + | + | | | | |Service Function| | + | + | | | |
|Forwarder(SFF) | | | | | | | |Forwarder(SFF) | | | | | | |
+--------------- +-------+-------+-------+--------+-------+---------+ +----------------+-------+-------+-------+--------+-------+---------+
|Service | | | | + | + | + | |Service | | | | + | + | + |
|Function (SF) | | | | | | | |Function (SF) | | | | | | |
+--------------- +-------+-------+-------+--------+-------+---------+ +----------------+-------+-------+-------+--------+-------+---------+
|SFC Proxy | + | + | | + | + | | |SFC Proxy | + | + | | + | + | |
+----------------+-------+-------+-------+--------+-------+---------+ +----------------+-------+-------+-------+--------+-------+---------+
Figure 7: NSH Action and Role Mapping Figure 7: NSH Action and Role Mapping
4. NSH Transport Encapsulation 4. NSH Transport Encapsulation
Once NSH is added to a packet, an outer encapsulation is used to Once NSH is added to a packet, an outer encapsulation is used to
forward the original packet and the associated metadata to the start forward the original packet and the associated metadata to the start
of a service chain. The encapsulation serves two purposes: of a service chain. The encapsulation serves two purposes:
1. Creates a topologically independent services plane. Packets are 1. Creates a topologically independent services plane. Packets are
forwarded to the required services without changing the forwarded to the required services without changing the
underlying network topology underlying network topology.
2. Transit network nodes simply forward the encapsulated packets as 2. Transit network nodes simply forward the encapsulated packets
is. without modification.
The service header is independent of the encapsulation used and is The service header is independent of the encapsulation used and is
encapsulated in existing transports. The presence of NSH is encapsulated in existing transports. The presence of NSH is
indicated via protocol type or other indicator in the outer indicated via protocol type or other indicator in the outer
encapsulation. encapsulation.
5. Fragmentation Considerations 5. Fragmentation Considerations
NSH and the associated transport header are "added" to the NSH and the associated transport header are "added" to the
encapsulated packet/frame. This additional information increases the encapsulated packet/frame. This additional information increases the
size of the packet. size of the packet.
As discussed in [I-D.ietf-rtgwg-dt-encap], within an administrative As discussed in [I-D.ietf-rtgwg-dt-encap], within an administrative
domain, an operator can ensure that the underlay MTU is sufficient to domain, an operator can ensure that the underlay MTU is sufficient to
carry SFC traffic without requiring fragmentation. carry SFC traffic without requiring fragmentation.
However, there will be cases where the underlay MTU is not large However, there will be cases where the underlay MTU is not large
enough to carry the NSH traffic. Since NSH does not provide enough to carry the NSH traffic. Since NSH does not provide
fragmentation support at the service plane, the transport/overlay fragmentation support at the service plane, the transport/overlay
layer MUST provide the requisite fragmentation handling. Section 6 layer MUST provide the requisite fragmentation handling. Section 9
of [I-D.ietf-rtgwg-dt-encap] provides guidance for those scenarios. of [I-D.ietf-rtgwg-dt-encap] provides guidance for those scenarios.
For example, when NSH is encapsulated in IP, IP-level fragmentation
coupled with Path MTU Discovery (PMTUD) is used. When, on the other
hand, the underlay does not support fragmentation procedures, an
error message SHOULD be logged when dropping a packet too big.
Lastly, NSH-specific fragmentation and reassembly methods may be
defined as well, but these methods are outside the scope of this
document.
6. Service Path Forwarding with NSH 6. Service Path Forwarding with NSH
6.1. SFFs and Overlay Selection 6.1. SFFs and Overlay Selection
As described above, NSH contains a Service Path Identifier (SPI) and As described above, NSH contains a Service Path Identifier (SPI) and
a Service Index (SI). The SPI is, as per its name, an identifier. a Service Index (SI). The SPI is, as per its name, an identifier.
The SPI alone cannot be used to forward packets along a service path. The SPI alone cannot be used to forward packets along a service path.
Rather the SPI provides a level of indirection between the service Rather the SPI provides a level of indirection between the service
path/topology and the network transport. Furthermore, there is no path/topology and the network transport. Furthermore, there is no
requirement, or expectation of an SPI being bound to a pre-determined requirement, or expectation of an SPI being bound to a pre-determined
skipping to change at page 15, line 46 skipping to change at page 16, line 48
select the appropriate network locator(s) for overlay forwarding. select the appropriate network locator(s) for overlay forwarding.
The logical SF may be a single SF, or a set of eligible SFs that are The logical SF may be a single SF, or a set of eligible SFs that are
equivalent. In the latter case, the SFF provides load distribution equivalent. In the latter case, the SFF provides load distribution
amongst the collection of SFs as needed. amongst the collection of SFs as needed.
SI serves as a mechanism for detecting invalid service function SI serves as a mechanism for detecting invalid service function
paths. In particular, an SI value of zero indicates that forwarding paths. In particular, an SI value of zero indicates that forwarding
is incorrect and the packet must be discarded. is incorrect and the packet must be discarded.
This indirection -- SPI to overlay -- creates a true service plane. This indirection -- SPI to overlay -- creates a true service plane.
That is the SFF/SF topology is constructed without impacting the That is, the SFF/SF topology is constructed without impacting the
network topology but more importantly service plane only participants network topology but more importantly, service plane only
(i.e., most SFs) need not be part of the network overlay topology and participants (i.e., most SFs) need not be part of the network overlay
its associated infrastructure (e.g., control plane, routing tables, topology and its associated infrastructure (e.g., control plane,
etc.) SFs need to be able to return a packet to an appropriate SFF routing tables, etc.) SFs need to be able to return a packet to an
(i.e., has the requisite NSH information) when service processing is appropriate SFF (i.e., has the requisite NSH information) when
complete. This can be via the over or underlay and in some case service processing is complete. This can be via the overlay or
require additional configuration on the SF. As mentioned above, an underlay and in some case require additional configuration on the SF.
existing overlay topology may be used provided it offers the As mentioned above, an existing overlay topology may be used provided
requisite connectivity. it offers the requisite connectivity.
The mapping of SPI to transport occurs on an SFF (as discussed above, The mapping of SPI to transport occurs on an SFF (as discussed above,
the first SFF in the path gets a NSH encapsulated packet from the the first SFF in the path gets an NSH encapsulated packet from the
Classifier). The SFF consults the SPI/ID values to determine the Classifier). The SFF consults the SPI/ID values to determine the
appropriate overlay transport protocol (several may be used within a appropriate overlay transport protocol (several may be used within a
given network) and next hop for the requisite SF. Table 1 below given network) and next hop for the requisite SF. Table 1 below
depicts an example of a single next-hop SPI/SI to network overlay depicts an example of a single next-hop SPI/SI to network overlay
network locator mapping. network locator mapping.
+------+------+---------------------+-------------------+ +------+------+---------------------+-------------------+
| SPI | SI | Next hop(s) | Transport | | SPI | SI | Next hop(s) | Transport |
+------+------+---------------------+-------------------+ +------+------+---------------------+-------------------+
| 10 | 255 | 192.0.2.1 | VXLAN-gpe | | 10 | 255 | 192.0.2.1 | VXLAN-gpe |
skipping to change at page 16, line 40 skipping to change at page 17, line 42
+------+------+---------------------+-------------------+ +------+------+---------------------+-------------------+
Table 1: SFF NSH Mapping Example Table 1: SFF NSH Mapping Example
Additionally, further indirection is possible: the resolution of the Additionally, further indirection is possible: the resolution of the
required SF network locator may be a localized resolution on an SFF, required SF network locator may be a localized resolution on an SFF,
rather than a service function chain control plane responsibility, as rather than a service function chain control plane responsibility, as
per Table 2 and Table 3 below. per Table 2 and Table 3 below.
Please note: VXLAN-gpe and GRE in the above table refer to Please note: VXLAN-gpe and GRE in the above table refer to
[I-D.ietf-nvo3-vxlan-gpe] and [RFC2784], respectively. [I-D.ietf-nvo3-vxlan-gpe] and [RFC2784] [RFC7676], respectively.
+------+-----+----------------+ +------+-----+----------------+
| SPI | SI | Next hop(s) | | SPI | SI | Next hop(s) |
+------+-----+----------------+ +------+-----+----------------+
| 10 | 3 | SF2 | | 10 | 3 | SF2 |
| | | | | | | |
| 245 | 12 | SF34 | | 245 | 12 | SF34 |
| | | | | | | |
| 40 | 9 | SF9 | | 40 | 9 | SF9 |
+------+-----+----------------+ +------+-----+----------------+
skipping to change at page 17, line 32 skipping to change at page 18, line 32
| SF34 | 198.51.100.34 | UDP | | SF34 | 198.51.100.34 | UDP |
| | | | | | | |
| SF9 | 2001:db8::1 | GRE | | SF9 | 2001:db8::1 | GRE |
+------+-------------------+-------------+ +------+-------------------+-------------+
Table 3: SF Locator Mapping Example Table 3: SF Locator Mapping Example
Since the SPI is a representation of the service path, the lookup may Since the SPI is a representation of the service path, the lookup may
return more than one possible next-hop within a service path for a return more than one possible next-hop within a service path for a
given SF, essentially a series of weighted (equally or otherwise) given SF, essentially a series of weighted (equally or otherwise)
paths to be used (for load distribution, redundancy or policy), see paths to be used (for load distribution, redundancy, or policy), see
Table 4. The metric depicted in Table 4 is an example to help Table 4. The metric depicted in Table 4 is an example to help
illustrated weighing SFs. In a real network, the metric will range illustrated weighing SFs. In a real network, the metric will range
from a simple preference (similar to routing next- hop), to a true from a simple preference (similar to routing next-hop), to a true
dynamic composite metric based on some service function-centric state dynamic composite metric based on some service function-centric state
(including load, sessions state, capacity, etc.) (including load, sessions state, capacity, etc.)
+------+-----+--------------+---------+ +------+-----+--------------+---------+
| SPI | SI | NH | Metric | | SPI | SI | NH | Metric |
+------+-----+--------------+---------+ +------+-----+--------------+---------+
| 10 | 3 | 203.0.113.1 | 1 | | 10 | 3 | 203.0.113.1 | 1 |
| | | | | | | | | |
| | | 203.0.113.2 | 1 | | | | 203.0.113.2 | 1 |
| | | | | | | | | |
| 20 | 12 | 192.0.2.1 | 1 | | 20 | 12 | 192.0.2.1 | 1 |
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Table 4: NSH Weighted Service Path Table 4: NSH Weighted Service Path
6.2. Mapping NSH to Network Transport 6.2. Mapping NSH to Network Transport
As described above, the mapping of SPI to network topology may result As described above, the mapping of SPI to network topology may result
in a single path, or it might result in a more complex topology. in a single path, or it might result in a more complex topology.
Furthermore, the SPI to overlay mapping occurs at each SFF Furthermore, the SPI to overlay mapping occurs at each SFF
independently. Any combination of topology selection is possible. independently. Any combination of topology selection is possible.
Please note, there is no requirement to create a new overlay topology Please note, there is no requirement to create a new overlay topology
if a suitable one already existing. NSH packets can use any (new or if a suitable one already exists. NSH packets can use any (new or
existing) overlay provided the requisite connectivity requirements existing) overlay provided the requisite connectivity requirements
are satisfied. are satisfied.
Examples of mapping for a topology: Examples of mapping for a topology:
1. Next SF is located at SFFb with locator 2001:db8::1 1. Next SF is located at SFFb with locator 2001:db8::1
SFFa mapping: SPI=10 --> VXLAN-gpe, dst-ip: 2001:db8::1 SFFa mapping: SPI=10 --> VXLAN-gpe, dst-ip: 2001:db8::1
2. Next SF is located at SFFc with multiple network locators for 2. Next SF is located at SFFc with multiple network locators for
load distribution purposes: load distribution purposes:
skipping to change at page 19, line 20 skipping to change at page 20, line 20
complex configuration and network protocol support to be extended to complex configuration and network protocol support to be extended to
the service path explicitly. In other words, the network operates as the service path explicitly. In other words, the network operates as
expected, and evolves as required, as does the service plane. expected, and evolves as required, as does the service plane.
6.3. Service Plane Visibility 6.3. Service Plane Visibility
The SPI and SI serve an important function for visibility into the The SPI and SI serve an important function for visibility into the
service topology. An operator can determine what service path a service topology. An operator can determine what service path a
packet is "on", and its location within that path simply by viewing packet is "on", and its location within that path simply by viewing
NSH information (packet capture, IPFIX, etc.) The information can be NSH information (packet capture, IPFIX, etc.) The information can be
used for service scheduling and placement decisions, troubleshooting used for service scheduling and placement decisions, troubleshooting,
and compliance verification. and compliance verification.
6.4. Service Graphs 6.4. Service Graphs
While a given realized service function path is a specific sequence While a given realized service function path is a specific sequence
of service functions, the service as seen by a user can actually be a of service functions, the service as seen by a user can actually be a
collection of service function paths, with the interconnection collection of service function paths, with the interconnection
provided by classifiers (in-service path, non-initial provided by classifiers (in-service path, non-initial
reclassification). These internal reclassifiers examine the packet reclassification). These internal reclassifiers examine the packet
at relevant points in the network, and, if needed, SPI and SI are at relevant points in the network, and, if needed, SPI and SI are
updated (whether this update is a re-write, or the imposition of a updated (whether this update is a re-write, or the imposition of a
new NSH with new values is implementation specific) to reflect the new NSH with new values is implementation specific) to reflect the
"result" of the classification. These classifiers may also of course "result" of the classification. These classifiers may also of course
modify the metadata associated with the packet. modify the metadata associated with the packet.
[RFC7665], Section 2.1 describes Service Graphs in detail. [RFC7665], Section 2.1 describes Service Graphs in detail.
7. Policy Enforcement with NSH 7. Policy Enforcement with NSH
7.1. NSH Metadata and Policy Enforcement 7.1. NSH Metadata and Policy Enforcement
As described in Section 3, NSH provides the ability to carry metadata As described in Section 2, NSH provides the ability to carry metadata
along a service path. This metadata may be derived from several along a service path. This metadata may be derived from several
sources, common examples include: sources, common examples include:
Network nodes/devices: Information provided by network nodes can Network nodes/devices: Information provided by network nodes can
indicate network-centric information (such as VRF or tenant) that indicate network-centric information (such as VRF or tenant) that
may be used by service functions, or conveyed to another network may be used by service functions, or conveyed to another network
node post service path egress. node post service path egress.
External (to the network) systems: External systems, such as External (to the network) systems: External systems, such as
orchestration systems, often contain information that is valuable orchestration systems, often contain information that is valuable
for service function policy decisions. In most cases, this for service function policy decisions. In most cases, this
information cannot be deduced by network nodes. For example, a information cannot be deduced by network nodes. For example, a
cloud orchestration platform placing workloads "knows" what cloud orchestration platform placing workloads "knows" what
application is being instantiated and can communicate this application is being instantiated and can communicate this
information to all NSH nodes via metadata carried in the context information to all NSH nodes via metadata carried in the context
header(s). header(s).
Service Functions: A classifier co-resident with Service Functions Service Functions: A classifier co-resident with Service Functions
often perform very detailed and valuable classification. In some often perform very detailed and valuable classification.
cases they may terminate, and be able to inspect encrypted
traffic.
Regardless of the source, metadata reflects the "result" of Regardless of the source, metadata reflects the "result" of
classification. The granularity of classification may vary. For classification. The granularity of classification may vary. For
example, a network switch, acting as a classifier, might only be able example, a network switch, acting as a classifier, might only be able
to classify based on a 5-tuple, whereas, a service function may be to classify based on a 5-tuple, whereas, a service function may be
able to inspect application information. Regardless of granularity, able to inspect application information. Regardless of granularity,
the classification information can be represented in NSH. the classification information can be represented in NSH.
Once the data is added to NSH, it is carried along the service path, Once the data is added to NSH, it is carried along the service path,
NSH-aware SFs receive the metadata, and can use that metadata for NSH-aware SFs receive the metadata, and can use that metadata for
local decisions and policy enforcement. Figure 8 and Figure 9 local decisions and policy enforcement. Figure 8 and Figure 9
highlight the relationship between metadata and policy: highlight the relationship between metadata and policy:
+-------+ +-------+ +-------+ +-------+ +-------+ +-------+
| SFF )------->( SFF |------->| SFF | | SFF )------->( SFF |------->| SFF |
+---^---+ +---|---+ +---|---+ +---+---+ +---+---+ +---+---+
^ | |
,-|-. ,-|-. ,-|-. ,-|-. ,-|-. ,-|-.
/ \ / \ / \ / \ / \ / \
( Class ) ( SF1 ) ( SF2 ) ( Class ) ( SF1 ) ( SF2 )
\ ify / \ / \ / \ ify / \ / \ /
`---' `---' `---' `---' `---' `---'
5-tuple: Permit Inspect 5-tuple: Permit Inspect
Tenant A Tenant A AppY Tenant A Tenant A AppY
AppY AppY
Figure 8: Metadata and Policy Figure 8: Metadata and Policy
skipping to change at page 21, line 18 skipping to change at page 22, line 18
^ | | ^ | |
,-+-. ,-+-. ,-+-. ,-+-. ,-+-. ,-+-.
/ \ / \ / \ / \ / \ / \
( Class ) ( SF1 ) ( SF2 ) ( Class ) ( SF1 ) ( SF2 )
\ ify / \ / \ / \ ify / \ / \ /
`-+-' `---' `---' `-+-' `---' `---'
| Permit Deny AppZ | Permit Deny AppZ
+---+---+ employees +---+---+ employees
| | | |
+-------+ +-------+
external External
system: system:
Employee Employee
AppZ AppZ
Figure 9: External Metadata and Policy Figure 9: External Metadata and Policy
In both of the examples above, the service functions perform policy In both of the examples above, the service functions perform policy
decisions based on the result of the initial classification: the SFs decisions based on the result of the initial classification: the SFs
did not need to perform re-classification, rather they rely on a did not need to perform re-classification, rather they rely on a
antecedent classification for local policy enforcement. antecedent classification for local policy enforcement.
skipping to change at page 21, line 44 skipping to change at page 22, line 44
intended recipients (which may include intended SFs only) . NSH intended recipients (which may include intended SFs only) . NSH
itself does not provide privacy functions, rather it relies on the itself does not provide privacy functions, rather it relies on the
transport/overlay layer. An operator can select the appropriate transport/overlay layer. An operator can select the appropriate
transport to ensure confidentially (and other security) transport to ensure confidentially (and other security)
considerations are met. Metadata privacy and security considerations considerations are met. Metadata privacy and security considerations
are a matter for the documents that define metadata format. are a matter for the documents that define metadata format.
7.2. Updating/Augmenting Metadata 7.2. Updating/Augmenting Metadata
Post-initial metadata imposition (typically performed during initial Post-initial metadata imposition (typically performed during initial
service path determination), metadata may be augmented or updated: service path determination), the metadata may be augmented or
updated:
1. Metadata Augmentation: Information may be added to NSH's existing 1. Metadata Augmentation: Information may be added to NSH's existing
metadata, as depicted in Figure 10. For example, if the initial metadata, as depicted in Figure 10. For example, if the initial
classification returns the tenant information, a secondary classification returns the tenant information, a secondary
classification (perhaps co-resident with DPI or SLB) may augment classification (perhaps co-resident with DPI or SLB) may augment
the tenant classification with application information, and the tenant classification with application information, and
impose that new information in NSH metadata. The tenant impose that new information in NSH metadata. The tenant
classification is still valid and present, but additional classification is still valid and present, but additional
information has been added to it. information has been added to it.
2. Metadata Update: Subsequent classifiers may update the initial 2. Metadata Update: Subsequent classifiers may update the initial
classification if it is determined to be incorrect or not classification if it is determined to be incorrect or not
descriptive enough. For example, the initial classifier adds descriptive enough. For example, the initial classifier adds
metadata that describes the traffic as "internet" but a security metadata that describes the traffic as "Internet" but a security
service function determines that the traffic is really "attack". service function determines that the traffic is really "attack".
Figure 11 illustrates an example of updating metadata. Figure 11 illustrates an example of updating metadata.
+-----+ +-----+ +-----+ +-----+ +-----+ +-----+
| SFF |---------> | SFF |----------> | SFF | | SFF |---------> | SFF |----------> | SFF |
+--+--+ +--+--+ +--+--+ +--+--+ +--+--+ +--+--+
^ | | ^ | |
,---. ,---. ,---. ,---. ,---. ,---.
/ \ / \ / \ / \ / \ / \
( Class ) ( SF1 ) ( SF2 ) ( Class ) ( SF1 ) ( SF2 )
\ / \ / \ / \ / \ / \ /
`-+-' `---' `---' `-+-' `---' `---'
| Inspect Deny | Inspect Deny
+---+---+ employees employee+ +---+---+ employees employee+
| | Class=AppZ appZ | | Class=AppZ appZ
+-------+ +-------+
external External
system: system:
Employee Employee
Figure 10: Metadata Augmentation Figure 10: Metadata Augmentation
+-----+ +-----+ +-----+ +-----+ +-----+ +-----+
| SFF |---------> | SFF |----------> | SFF | | SFF |---------> | SFF |----------> | SFF |
+--+--+ +--+--+ +--+--+ +--+--+ +--+--+ +--+--+
^ | | ^ | |
,---. ,---. ,---. ,---. ,---. ,---.
skipping to change at page 23, line 18 skipping to change at page 24, line 18
the Service Path Identifier values can represent the result of the Service Path Identifier values can represent the result of
classification. A given SPI can be defined based on classification classification. A given SPI can be defined based on classification
results (including metadata classification). The imposition of the results (including metadata classification). The imposition of the
SPI and SI results in the packet being placed on the newly specified SPI and SI results in the packet being placed on the newly specified
SFP at the position indicated by the imposed SPI and SI. SFP at the position indicated by the imposed SPI and SI.
This relationship provides the ability to create a dynamic service This relationship provides the ability to create a dynamic service
plane based on complex classification without requiring each node to plane based on complex classification without requiring each node to
be capable of such classification, or requiring a coupling to the be capable of such classification, or requiring a coupling to the
network topology. This yields service graph functionality as network topology. This yields service graph functionality as
described in Section 7.4. Figure 12 illustrates an example of this described in Section 6.4. Figure 12 illustrates an example of this
behavior. behavior.
+-----+ +-----+ +-----+ +-----+ +-----+ +-----+
| SFF |---------> | SFF |------+---> | SFF | | SFF |---------> | SFF |------+---> | SFF |
+--+--+ +--+--+ | +--+--+ +--+--+ +--+--+ | +--+--+
| | | | | | | |
,---. ,---. | ,---. ,---. ,---. | ,---.
/ \ / SF1 \ | / \ / \ / SF1 \ | / \
( SCL ) ( + ) | ( SF2 ) ( SCL ) ( + ) | ( SF2 )
\ / \SCL2 / | \ / \ / \SCL2 / | \ /
skipping to change at page 23, line 49 skipping to change at page 24, line 49
DoS DoS
"Scrubber" "Scrubber"
Figure 12: Path ID and Metadata Figure 12: Path ID and Metadata
Specific algorithms for mapping metadata to an SPI are outside the Specific algorithms for mapping metadata to an SPI are outside the
scope of this document. scope of this document.
8. Security Considerations 8. Security Considerations
As with many other protocols, NSH data can be spoofed or otherwise As with many other protocols, the NSH encapsulation could be spoofed
modified. In many deployments, NSH will be used in a controlled or otherwise modified in transit. However, the deployment scope (as
environment, with trusted devices (e.g., a data center) thus defined in [RFC7665]) of the NSH encapsulation is limited to a single
mitigating the risk of unauthorized header manipulation. network administrative domain as a controlled environment, with
trusted devices (e.g., a data center) thus mitigating the risk of
unauthorized manipulation of the encapsulation headers or metadata.
NSH is always encapsulated in a transport protocol and therefore, NSH is always encapsulated in a transport protocol (as detailed in
when required, existing security protocols that provide authenticity Section 4 of this specification) and therefore, when required,
(e.g., [RFC6071]) can be used. Similarly, if confidentiality is existing security protocols that provide authenticity (e.g.,
required, existing encryption protocols can be used in conjunction [RFC6071]) can be used. Similarly, if confidentiality is required,
with encapsulated NSH. existing encryption protocols can be used in conjunction with the NSH
encapsulation.
Further, existing best practices, such as [BCP38] should be deployed Further, existing best practices, such as [BCP38] SHOULD be deployed
at the network layer to ensure that traffic entering the service path at the network layer to ensure that traffic entering the service path
is indeed "valid". [I-D.ietf-rtgwg-dt-encap] provides additional is indeed "valid". [I-D.ietf-rtgwg-dt-encap] provides additional
transport encapsulation considerations. transport encapsulation considerations.
NSH metadata authenticity and confidentiality must be considered as Even though much of the metadata carried within the NSH encapsulation
well. In order to protect the metadata, an operator can leverage the is derived from the packet contents, and thus is not privacy or
aforementioned mechanisms provided the transport layer, authenticity security sensitive, NSH metadata authenticity and confidentiality
and/or confidentiality. An operator MUST carefully select the must be considered as well. In order to protect the metadata, an
transport/underlay services to ensure end to end security services, operator can leverage the aforementioned mechanisms provided by the
when those are sought after. For example, if [RFC6071] is used, the transport layer including authenticity and/or confidentiality. An
operator MUST ensure it can be supported by the transport/underlay of operator MUST carefully select the transport/underlay services to
all relevant network segments as well as SFF and SFs. Further, as ensure end-to-end security services, when those are sought. For
described in Section 8.1, operators can and should use indirect example, if [RFC6071] is used, the operator MUST ensure it can be
identification for personally identifying information, thus supported by the transport/underlay of all relevant network segments
significantly mitigating the risk of privacy violation. Means to as well as SFFs and SFs in the service path. Further, as described
prevent leaking privacy-related information outside an administrative under the "SFC Encapsulation" area of the Security Considerations of
domain are natively supported by NSH given that the last SFF of a [RFC7665], operators can and should use indirect identification for
path will systematically remove the NSH header before forwarding a metadata deemed to be sensitive (such as personally identifying
packet upstream. information), thus significantly mitigating the risk of privacy
violation. In particular, subscriber identifying information should
be handled carefully, and in general should be obfuscated. This is
covered in the Security Considerations of [RFC7665]. For those
situations where obfuscation is either inapplicable or judged to be
insufficient, one can also encrypt the metadata. An approach to an
optional capability to do this was explored
[I-D.reddy-sfc-nsh-encrypt]. Means to prevent leaking privacy-
related information outside an administrative domain are natively
supported by NSH given that the last SFF of a servicepath will
systematically remove the NSH encapsulation before forwarding a
packet exiting the service path.
Lastly, SF security, although out of scope of this document, should Lastly, SF security, although out of scope of this document, should
be considered, particularly if an SF needs to access, authenticate or be considered, particularly if an SF needs to access, authenticate,
update NSH metadata. or update the NSH encapsulation or metadata. However, again the
placement of SFs is assumed to be bounded within the scope of a
single administrative domain and therefore under direct control of
the operator.
9. Contributors 9. Contributors
This WG document originated as draft-quinn-sfc-nsh and had the This WG document originated as draft-quinn-sfc-nsh and had the
following co-authors and contributors. The editors of this document following co-authors and contributors. The editors of this document
would like to thank and recognize them and their contributions. would like to thank and recognize them and their contributions.
These co-authors and contributors provided invaluable concepts and These co-authors and contributors provided invaluable concepts and
content for this document's creation. content for this document's creation.
Surendra Kumar Surendra Kumar
skipping to change at page 27, line 13 skipping to change at page 28, line 29
this document. this document.
Loa Andersson provided a thorough review and valuable comments, we Loa Andersson provided a thorough review and valuable comments, we
thank him for that. thank him for that.
Reinaldo Penno deserves a particular thank you for his architecture Reinaldo Penno deserves a particular thank you for his architecture
and implementation work that helped guide the protocol concepts and and implementation work that helped guide the protocol concepts and
design. design.
The editors also acknowledge comprehensive reviews and respective The editors also acknowledge comprehensive reviews and respective
suggestions by Med Boucadair and Adrian Farrel. suggestions by Med Boucadair, Adrian Farrel, Juergen Schoenwaelder,
and Acee Lindem.
Lastly, David Dolson has provides significant review, feedback and Lastly, David Dolson has provides significant review, feedback and
suggestions throughout the evolution of this document. His suggestions throughout the evolution of this document. His
contributions are very much appreciated. contributions are very much appreciated.
11. IANA Considerations 11. IANA Considerations
11.1. NSH EtherType 11.1. NSH EtherType
An IEEE EtherType, 0x894F, has been allocated for NSH. An IEEE EtherType, 0x894F, has been allocated for NSH.
11.2. Network Service Header (NSH) Parameters 11.2. Network Service Header (NSH) Parameters
IANA is requested to create a new "Network Service Header (NSH) IANA is requested to create a new "Network Service Header (NSH)
Parameters" registry. The following sub-sections request new Parameters" registry. The following sub-sections request new
registries within the "Network Service Header (NSH) Parameters " registries within the "Network Service Header (NSH) Parameters "
registry. registry.
11.2.1. NSH Base Header Unassigned Bits 11.2.1. NSH Base Header Bits
There are five unassigned bits in the NSH Base Header. New bits are There are five unassigned bits (U bits) in the NSH Base Header, and
assigned via Standards Action [RFC8126]. one assigned bit (O bit). New bits are assigned via Standards Action
[RFC8126].
Bit 2 - O (OAM) bit
Bit 3 - Unassigned Bit 3 - Unassigned
Bits 16-19 - Unassigned Bits 16-19 - Unassigned
11.2.2. NSH Version 11.2.2. NSH Version
IANA is requested to setup a registry of "NSH Version". New values IANA is requested to setup a registry of "NSH Version". New values
are assigned via Standards Action [RFC8126]. are assigned via Standards Action [RFC8126].
Version 00b: This protocol version. This document. Version 00b: This protocol version. This document.
Version 01b: Reserved. This document. Version 01b: Reserved. This document.
skipping to change at page 28, line 30 skipping to change at page 29, line 50
| | | | | | | |
| 0x3..0xE | Unassigned | | | 0x3..0xE | Unassigned | |
| | | | | | | |
| 0xF | Experimentation | This document | | 0xF | Experimentation | This document |
+----------+-----------------+---------------+ +----------+-----------------+---------------+
Table 5: MD Type Values Table 5: MD Type Values
11.2.4. MD Class Registry 11.2.4. MD Class Registry
IANA is requested to set up a registry of "MD Class". These are 16- IANA is requested to set up a registry of "MD Class". These are
bit values. New allocations are to be made according to the 16-bit values. New allocations are to be made according to the
following policies: following policies:
0x0000 to 0x01ff: IETF Review 0x0000 to 0x01ff: IETF Review
0x0200 to 0xfff5: Expert Review 0x0200 to 0xfff5: Expert Review
0xfff6 to 0xfffe: Experimental 0xfff6 to 0xfffe: Experimental
0xffff: Reserved 0xffff: Reserved
IANA is requested to assign the values as per Table 6:: IANA is requested to assign the values as per Table 6::
+-----------+-----------------------------+------------+ +-----------+-----------------------------+------------+
skipping to change at page 29, line 38 skipping to change at page 31, line 29
| | | | | | | |
| 0x6..0xFD | Unassigned | | | 0x6..0xFD | Unassigned | |
| | | | | | | |
| 0xFE | Experiment 1 | This document | | 0xFE | Experiment 1 | This document |
| | | | | | | |
| 0xFF | Experiment 2 | This document | | 0xFF | Experiment 2 | This document |
+---------------+--------------+---------------+ +---------------+--------------+---------------+
Table 7: NSH Base Header Next Protocol Values Table 7: NSH Base Header Next Protocol Values
11.2.6. New IETF assigned MD Type Registry 11.2.6. New IETF Assigned Optional Variable Length Metadata Type
Registry
This document requests IANA to create a registry for the type values This document requests IANA to create a registry for the type values
owned by the IETF (i.e., MD Class set to 0x0000) called the "IETF owned by the IETF (i.e., MD Class set to 0x0000) called the "IETF
Assigned MD Type Registry." Assigned Optional Variable Length Metadata Type Registry", as
specified in Section 2.5.1.
The type values are assigned via Standards Action [RFC8126]. The type values are assigned via Standards Action [RFC8126].
No initial values are assigned at the creation of the registry. No initial values are assigned at the creation of the registry.
12. References 12. References
12.1. Normative References 12.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
skipping to change at page 31, line 17 skipping to change at page 33, line 11
R., and A. Ghanwani, "Service Function Chaining Operation, R., and A. Ghanwani, "Service Function Chaining Operation,
Administration and Maintenance Framework", draft-ietf-sfc- Administration and Maintenance Framework", draft-ietf-sfc-
oam-framework-02 (work in progress), July 2017. oam-framework-02 (work in progress), July 2017.
[I-D.napper-sfc-nsh-broadband-allocation] [I-D.napper-sfc-nsh-broadband-allocation]
Napper, J., Kumar, S., Muley, P., Henderickx, W., and M. Napper, J., Kumar, S., Muley, P., Henderickx, W., and M.
Boucadair, "NSH Context Header Allocation -- Broadband", Boucadair, "NSH Context Header Allocation -- Broadband",
draft-napper-sfc-nsh-broadband-allocation-03 (work in draft-napper-sfc-nsh-broadband-allocation-03 (work in
progress), July 2017. progress), July 2017.
[I-D.reddy-sfc-nsh-encrypt]
Reddy, T., Patil, P., Fluhrer, S., and P. Quinn,
"Authenticated and encrypted NSH service chains", draft-
reddy-sfc-nsh-encrypt-00 (work in progress), April 2015.
[RFC2784] Farinacci, D., Li, T., Hanks, S., Meyer, D., and P. [RFC2784] Farinacci, D., Li, T., Hanks, S., Meyer, D., and P.
Traina, "Generic Routing Encapsulation (GRE)", RFC 2784, Traina, "Generic Routing Encapsulation (GRE)", RFC 2784,
DOI 10.17487/RFC2784, March 2000, DOI 10.17487/RFC2784, March 2000,
<http://www.rfc-editor.org/info/rfc2784>. <http://www.rfc-editor.org/info/rfc2784>.
[RFC3692] Narten, T., "Assigning Experimental and Testing Numbers [RFC3692] Narten, T., "Assigning Experimental and Testing Numbers
Considered Useful", BCP 82, RFC 3692, Considered Useful", BCP 82, RFC 3692,
DOI 10.17487/RFC3692, January 2004, DOI 10.17487/RFC3692, January 2004,
<http://www.rfc-editor.org/info/rfc3692>. <http://www.rfc-editor.org/info/rfc3692>.
skipping to change at page 31, line 42 skipping to change at page 33, line 41
[RFC7325] Villamizar, C., Ed., Kompella, K., Amante, S., Malis, A., [RFC7325] Villamizar, C., Ed., Kompella, K., Amante, S., Malis, A.,
and C. Pignataro, "MPLS Forwarding Compliance and and C. Pignataro, "MPLS Forwarding Compliance and
Performance Requirements", RFC 7325, DOI 10.17487/RFC7325, Performance Requirements", RFC 7325, DOI 10.17487/RFC7325,
August 2014, <http://www.rfc-editor.org/info/rfc7325>. August 2014, <http://www.rfc-editor.org/info/rfc7325>.
[RFC7498] Quinn, P., Ed. and T. Nadeau, Ed., "Problem Statement for [RFC7498] Quinn, P., Ed. and T. Nadeau, Ed., "Problem Statement for
Service Function Chaining", RFC 7498, Service Function Chaining", RFC 7498,
DOI 10.17487/RFC7498, April 2015, DOI 10.17487/RFC7498, April 2015,
<http://www.rfc-editor.org/info/rfc7498>. <http://www.rfc-editor.org/info/rfc7498>.
[RFC7676] Pignataro, C., Bonica, R., and S. Krishnan, "IPv6 Support
for Generic Routing Encapsulation (GRE)", RFC 7676,
DOI 10.17487/RFC7676, October 2015,
<http://www.rfc-editor.org/info/rfc7676>.
Authors' Addresses Authors' Addresses
Paul Quinn (editor) Paul Quinn (editor)
Cisco Systems, Inc. Cisco Systems, Inc.
Email: paulq@cisco.com Email: paulq@cisco.com
Uri Elzur (editor) Uri Elzur (editor)
Intel Intel
Email: uri.elzur@intel.com Email: uri.elzur@intel.com
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