Service Function Chaining P. Quinn, Ed.
Internet-Draft Cisco Systems, Inc.
Intended status: Standards Track U. Elzur, Ed.
Expires: March 24, 2017 Intel
September 20, 2016
Network Service Header
draft-ietf-sfc-nsh-10.txt
Abstract
This document describes a Network Service Header (NSH) inserted onto
packets or frames to realize service function paths. NSH also
provides a mechanism for metadata exchange along the instantiated
service path. NSH is the SFC encapsulation required to support the
Service Function Chaining (SFC) Architecture (defined in RFC7665).
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1. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
Status of this Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on March 24, 2017.
Copyright Notice
Copyright (c) 2016 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
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to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
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Table of Contents
1. Requirements Language . . . . . . . . . . . . . . . . . . . . 2
2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.1. Definition of Terms . . . . . . . . . . . . . . . . . . . 4
2.2. Problem Space . . . . . . . . . . . . . . . . . . . . . . 5
2.3. NSH-based Service Chaining . . . . . . . . . . . . . . . . 5
3. Network Service Header . . . . . . . . . . . . . . . . . . . . 7
3.1. Network Service Header Format . . . . . . . . . . . . . . 7
3.2. NSH Base Header . . . . . . . . . . . . . . . . . . . . . 7
3.3. Service Path Header . . . . . . . . . . . . . . . . . . . 10
3.4. NSH MD Type 1 . . . . . . . . . . . . . . . . . . . . . . 10
3.5. NSH MD Type 2 . . . . . . . . . . . . . . . . . . . . . . 11
3.5.1. Optional Variable Length Metadata . . . . . . . . . . 12
4. NSH Actions . . . . . . . . . . . . . . . . . . . . . . . . . 14
5. NSH Encapsulation . . . . . . . . . . . . . . . . . . . . . . 16
6. Fragmentation Considerations . . . . . . . . . . . . . . . . . 17
7. Service Path Forwarding with NSH . . . . . . . . . . . . . . . 18
7.1. SFFs and Overlay Selection . . . . . . . . . . . . . . . . 18
7.2. Mapping NSH to Network Transport . . . . . . . . . . . . . 20
7.3. Service Plane Visibility . . . . . . . . . . . . . . . . . 21
7.4. Service Graphs . . . . . . . . . . . . . . . . . . . . . . 21
8. Policy Enforcement with NSH . . . . . . . . . . . . . . . . . 22
8.1. NSH Metadata and Policy Enforcement . . . . . . . . . . . 22
8.2. Updating/Augmenting Metadata . . . . . . . . . . . . . . . 24
8.3. Service Path Identifier and Metadata . . . . . . . . . . . 25
9. Security Considerations . . . . . . . . . . . . . . . . . . . 27
10. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 28
11. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 31
12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 32
12.1. NSH EtherType . . . . . . . . . . . . . . . . . . . . . . 32
12.2. Network Service Header (NSH) Parameters . . . . . . . . . 32
12.2.1. NSH Base Header Reserved Bits . . . . . . . . . . . . 32
12.2.2. NSH Version . . . . . . . . . . . . . . . . . . . . . 32
12.2.3. MD Type Registry . . . . . . . . . . . . . . . . . . . 32
12.2.4. MD Class Registry . . . . . . . . . . . . . . . . . . 33
12.2.5. NSH Base Header Next Protocol . . . . . . . . . . . . 33
13. References . . . . . . . . . . . . . . . . . . . . . . . . . . 35
13.1. Normative References . . . . . . . . . . . . . . . . . . . 35
13.2. Informative References . . . . . . . . . . . . . . . . . . 35
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 37
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2. Introduction
Service functions are widely deployed and essential in many networks.
These service functions provide a range of features such as security,
WAN acceleration, and server load balancing. Service functions may
be instantiated at different points in the network infrastructure
such as the wide area network, data center, campus, and so forth.
Prior to development of the SFC architecture [RFC7665] and the
protocol specified in this document, current service function
deployment models have been relatively static, and bound to topology
for insertion and policy selection. Furthermore, they do not adapt
well to elastic service environments enabled by virtualization.
New data center network and cloud architectures require more flexible
service function deployment models. Additionally, the transition to
virtual platforms requires an agile service insertion model that
supports dynamic and elastic service delivery; the movement of
service functions and application workloads in the network and the
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.
NSH defines a new service plane protocol specifically for the
creation of dynamic service chains and is composed of the following
elements:
1. Service Function Path identification
2. Transport independent service function chain
3. Per-packet network and service metadata or optional variable
type-length-value (TLV) metadata.
NSH is designed to be easy to implement across a range of devices,
both physical and virtual, including hardware platforms.
An NSH-aware control plane is outside the scope of this document.
[RFC7665] provides an overview of a service chaining architecture
that clearly defines the roles of the various elements and the scope
of a service function chaining encapsulation. NSH is the SFC
encapsulation referenced in RFC7665.
2.1. Definition of Terms
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Classification: Defined in [RFC7665].
Classifier: Defined in [RFC7665].
Metadata: Defined in [RFC7665].
Network Locator: dataplane address, typically IPv4 or IPv6, used to
send and receive network traffic.
Network Node/Element: Device that forwards packets or frames based
on outer header (i.e. transport) information.
Network Overlay: Logical network built on top of existing network
(the underlay). Packets are encapsulated or tunneled to create
the overlay network topology.
Service Classifier: Logical entity providing classification
function. Since they are logical, classifiers may be co-resident
with SFC elements such as SFs or SFFs. Service classifiers
perform classification and impose NSH. The initial classifier
imposes the initial NSH and sends the NSH packet to the first SFF
in the path. Non-initial (i.e. subsequent) classification can
occur as needed and can alter, or create a new service path.
Service Function (SF): Defined in [RFC7665].
Service Function Chain (SFC): Defined in [RFC7665].
Service Function Forwarder (SFF): Defined in [RFC7665].
Service Function Path (SFP): Defined in [RFC7665].
SFC Proxy: Defined in [RFC7665].
2.2. Problem Space
Network Service Header (NSH) addresses several limitations associated
with service function deployments. [RFC7498] provides a
comprehensive review of those issues.
2.3. NSH-based Service Chaining
The NSH creates a dedicated service plane, more specifically, NSH
enables:
1. Topological Independence: Service forwarding occurs within the
service plane, the underlying network topology does not require
modification. NSH provides an identifier used to select the
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network overlay for network forwarding.
2. Service Chaining: NSH enables service chaining per [RFC7665].
NSH contains path identification information needed to realize a
service path. Furthermore, NSH provides the ability to monitor
and troubleshoot a service chain, end-to-end via service-specific
OAM messages. The NSH fields can be used by administrators (via,
for example a traffic analyser) to verify (account, ensure
correct chaining, provide reports, etc.) the path specifics of
packets being forwarded along a service path.
3. NSH provides a mechanism to carry shared metadata between
participating entities and service functions. The semantics of
the shared metadata is communicated via a control plane, which is
outside the scope of this document, to participating nodes.
[SFC-CP] provides an example of such in section 3.3. Examples of
metadata include classification information used for policy
enforcement and network context for forwarding post service
delivery.
4. Classification and re-classification: sharing the metadata allows
service functions to share initial and intermediate
classification results with downstream service functions saving
re-classification, where enough information was enclosed.
5. NSH offers a common and standards-based header for service
chaining to all network and service nodes.
6. Transport Agnostic: NSH is transport independent. An appropriate
(for a given deployment) network transport protocol can be used
to transport NSH-encapsulated traffic. This transport may form
an overlay network and if an existing overlay topology provides
the required service path connectivity, that existing overlay may
be used.
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3. Network Service Header
A Network Service Header (NSH) contains service path information and
optionally metadata that 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/frame, for network forwarding.
A Service Classifier adds the NSH. The NSH is removed by the last
SFF in the service chain or by a SF that consumes the packet.
3.1. Network Service Header Format
An NSH is composed of a 4-byte (all references to bytes in this draft
refer to 8-bit bytes, or octets) Base Header, a 4-byte Service Path
Header and Context Headers, as shown in Figure 1 below.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Base Header |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Service Path Header |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Context Headers ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: Network Service Header
Base header: provides information about the service header and the
payload protocol.
Service Path Header: provide path identification and location within
a service path.
Context headers: carry metadata (i.e. context data) along a service
path.
3.2. NSH Base Header
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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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Figure 2: NSH Base Header
Base Header Field Descriptions:
Version: The version field is used to ensure backward compatibility
going forward with future NSH updates. It MUST be set to 0x0 by the
sender, in this first revision of NSH. Given the widespread
implementation of existing hardware that uses the first nibble after
an MPLS label stack for ECMP decision processing, this document
reserves version 01 and this value MUST NOT be used in future
versions of the protocol. Please see [RFC7325] for further
discussion of MPLS-related forwarding requirements.
O bit: Setting this bit indicates an Operations, Administration, and
Maintenance (OAM) packet. The actual packet format and processing of
SFC OAM messages is outside the scope of this specification (see [I-
D.ietf-sfc-oam-framework]).
SF/SFF/SFC Proxy/Classifer implementations, which do not support SFC
OAM procedures, SHALL discard packets with O-bit set.
SF/SFF/SFC Proxy/Classifer implementations MAY support a configurable
parameter to enable forwarding received SFC OAM packets unmodified to
the next element in the chain. Such behavior may be acceptable for a
subset of OAM functions, but can result in unexpected outcomes for
others, thus it is recommended to analyze the impact of forwarding an
OAM packet for all OAM functions prior to enabling this behavior.
The configurable parameter MUST be disabled by default.
For non OAM packets, the O-bit MUST be cleared and MUST NOT be
modified along the SFP.
C bit: Indicates that a critical metadata TLV is present. This bit
acts as an indication for hardware implementers to decide how to
handle the presence of a critical TLV without necessarily needing to
parse all TLVs present. For an MD Type of 0x1 (i.e. no variable
length metadata is present), the C bit MUST be set to 0x0.
All other flag fields are reserved for future use. Reserved bits
MUST be set to zero when sent and MUST be ignored upon receipt.
Length: total length, in 4-byte words, of NSH including the Base
Header, the Service Path Header and the context headers or optional
variable length metadata. The Length MUST be of value 0x6 for MD
Type equal to 0x1 and MUST be of value 0x2 or greater for MD Type
equal to 0x2. The NSH header length MUST be an integer number of 4
bytes. The length field indicates the "end" of NSH and where the
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original packet/frame begins.
MD Type: indicates the format of NSH beyond the mandatory Base Header
and the Service Path Header. MD Type defines the format of the
metadata being carried. Please see IANA Considerations section
below.
NSH defines two MD types:
0x1 - which indicates that the format of the header includes fixed
length context headers (see Figure 4 below).
0x2 - which does not mandate any headers beyond the Base Header and
Service Path Header, but may contain optional variable length context
information.
The format of the base header and the service path header is
invariant, and not affected by MD Type.
NSH implementations MUST support MD Type = 0x1, and SHOULD support MD
Type = 0x2. There exists, however, a middle ground, wherein a device
will support MD Type 0x1 (as per the MUST) metadata, yet be deployed
in a network with MD Type 0x2 metadata packets. In that case, the MD
Type 0x1 node, MUST utilize the base header length field to determine
the original payload offset if it requires access to the original
packet/frame.
Next Protocol: indicates the protocol type of the encapsulated data.
NSH does not alter the inner payload, and the semantics on the inner
protocol remain unchanged due to NSH service function chaining.
Please see IANA Considerations section below.
This draft defines the following Next Protocol values:
0x1 : IPv4
0x2 : IPv6
0x3 : Ethernet
0x4: NSH
0x5: MPLS
0x6-0xFD: Unassigned
0xFE-0xFF: Experimental
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3.3. Service Path Header
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Service Path Identifier (SPI) | Service Index |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Service Path Identifier (SPI): 24 bits
Service Index (SI): 8 bits
Figure 3: NSH Service Path Header
Service Path Identifier (SPI): identifies a service path.
Participating nodes MUST use this identifier for Service Function
Path selection. The initial classifier MUST set the appropriate SPI
for a given classification result.
Service Index (SI): provides location within the SFP. The initial
classifier MUST set the appropriate SI value for a given
classification result. The initial SI value SHOULD default to 255.
However, the classifier MUST allow configuration of other SI values.
Service Index MUST be decremented by Service Functions or by SFC
Proxy nodes after performing required services and the new
decremented SI value MUST be used in the egress NSH packet. The
initial Classifier MUST send the packet to the first SFF in the
identified SFP for forwarding along an SFP. If re-classification
occurs, and that re-classification results in a new SPI, the
(re)classifier is, in effect, the initial classifier for the
resultant SPI.
SI SHOULD be used in conjunction with SPI for SFP selection and,
consequently, determining the next SFF/SF in the path. Service Index
(SI) is also valuable when troubleshooting/ reporting service paths.
When an SPI and SI do not correspond to a valid next hop in a SFP, it
is an error and the SFF SHOULD generate an error/log message. The
value zero for SI is not valid and indicates a broken SFC or
malfunctioning SF. In addition to indicating the location within a
Service Function Path, SI can be used for service plane loop
detection.
3.4. NSH MD Type 1
When the Base Header specifies MD Type = 0x1, four Context Headers,
4-byte each, MUST be added immediately following the Service Path
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Header, as per Figure 4. Context Headers that carry no metadata MUST
be set to zero.
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=0x1 | Next Protocol |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Service Path Identifer | Service Index |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Mandatory Context Header |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Mandatory Context Header |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Mandatory Context Header |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Mandatory Context Header |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4: NSH MD Type=0x1
[dcalloc] and [broadalloc] provide specific examples of how metadata
can be allocated.
3.5. NSH MD Type 2
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
optional Variable Length Context Headers MUST be of an integer number
of 4-bytes. The base header length field MUST be used to determine
the offset to locate the original packet or frame for SFC nodes that
require access to that information.
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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=0x2 | Next Protocol |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Service Path Identifier | Service Index |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Variable Length Context Headers (opt.) ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 5: NSH MD Type=0x2
3.5.1. Optional Variable Length Metadata
The format of the optional variable length context headers, is as
described below.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Metadata Class |C| Type |R| Len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Variable Metadata |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 6: Variable Context Headers
Metadata Class (MD Class): The MD Class defines the scope of the
'Type' field to provide a hierarchical namespace. The IANA
Considerations section defines how the MD Class values can be
allocated to standards bodies, vendors, and others.
Type: the Type field is split into two ranges - 0 to 127 for non-
critical options and 128-255 for critical options. While the value
allocation is the responsibility of the MD Class owner, critical
options MUST NOT be allocated from the 0 to 127 range and non-
critical options MUST NOT be allocated from the 128-255 range.
Figure 7 below illustrates the placement of the Critical bit within
the Type field.
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+-+-+-+-+-+-+-+-+
|C| Type |
+-+-+-+-+-+-+-+-+
Figure 7: Critical Bit Placement Within the TLV Type Field
If an NSH-aware node receives an encapsulated packet containing a TLV
with the Critical bit set to 0x1 in the Type field and it does not
understand how to process the Type, it MUST drop the packet. Transit
devices (i.e. network nodes that do not participate in the service
plane) MUST NOT drop packets based on the setting of this bit.
Reserved bit: one reserved bit is present for future use. The
reserved bits MUST be set to 0x0.
Length: Length of the variable metadata, in single byte words. In
case the metadata length is not an integer number of 4-byte words,
the sender MUST add pad bytes immediately following the last metadata
byte to extend the metadata to an integer number of 4-byte words.
The receiver MUST round up the length field to the nearest 4-byte
word boundary, to locate and process the next field in the packet.
The receiver MUST access only those bytes in the metadata indicated
by the length field (i.e. actual number of single byte words) and
MUST ignore the remaining bytes up to the nearest 4-byte word
boundary. A value of 0x0 or higher can be used.
A value of 0x0 denotes a TLV header without a Variable Metadata
field.
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4. NSH Actions
NSH-aware nodes are the only nodes that MAY alter the content of the
NSH headers. NSH-aware nodes include: service classifiers, SFF, SF
and SFC proxies. These nodes have several possible header related
actions:
1. Insert or remove NSH: These actions can occur at the start and
end respectively of a service path. Packets are classified, and
if determined to require servicing, NSH will be imposed. A
service classifier MUST insert NSH at the start of an SFP. An
imposed NSH MUST contain valid Base Header and Service Path
Header. At the end of a service function path, a SFF, MUST be
the last node operating on the service header and MUST remove it.
Multiple logical classifiers may exist within a given service
path. Non-initial classifiers may re-classify data and that re-
classification MAY result in a new Service Function Path. When
the logical classifier performs re-classification that results in
a change of service path, it MUST remove the existing NSH and
MUST impose a new NSH with the Base Header and Service Path
Header reflecting the new service path information and set the
initial SI. Metadata MAY be preserved in the new NSH.
2. Select service path: The Service Path Header provides service
chain information and is used by SFFs to determine correct
service path selection. SFFs MUST use the Service Path Header
for selecting the next SF or SFF in the service path.
3. Update NSH: NSH-aware service functions (SF) MUST decrement the
service index. If an 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 MUST be dropped by the SFF.
Classifier(s) MAY update Context Headers if new/updated context
is available.
If an SFC proxy is in use (acting on behalf of a non-NSH-aware
service function for NSH actions), then the proxy MUST update
Service Index and MAY update contexts. When an SFC proxy
receives an NSH-encapsulated packet, it MUST remove the NSH
headers before 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 with the correct NSH, and MUST decrement the
Service Index.
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4. Service policy selection: Service Function instances derive
policy (i.e. service actions such as permit or deny) selection
and enforcement from the service header. Metadata shared in the
service header can provide a range of service-relevant
information such as traffic classification. Service functions
SHOULD use NSH to select local service policy.
Figure 8 maps each of the four actions above to the components in the
SFC architecture that can perform it.
+---------------+------------------+-------+----------------+---------+
| | Insert |Select | Update |Service |
| | or remove NSH |Service| NSH |policy |
| | |Function| |selection|
| Component +--------+--------+Path +----------------+ |
| | | | | Dec. |Update | |
| | Insert | Remove | |Service |Context| |
| | | | | Index |Header | |
+----------------+--------+--------+-------+--------+-------+---------+
| | + | + | | | + | |
|Classifier | | | | | | |
+--------------- +--------+--------+-------+--------+-------+---------+
|Service Function| | + | + | | | |
|Forwarder(SFF) | | | | | | |
+--------------- +--------+--------+-------+--------+-------+---------+
|Service | | | | + | + | + |
|Function (SF) | | | | | | |
+--------------- +--------+--------+-------+--------+-------+---------+
|SFC Proxy | + | + | | + | | |
+----------------+--------+--------+-------+--------+-------+---------+
Figure 8: NSH Action and Role Mapping
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5. NSH Encapsulation
Once NSH is added to a packet, an outer encapsulation is used to
forward the original packet and the associated metadata to the start
of a service chain. The encapsulation serves two purposes:
1. Creates a topologically independent services plane. Packets are
forwarded to the required services without changing the
underlying network topology
2. Transit network nodes simply forward the encapsulated packets as
is.
The service header is independent of the encapsulation used and is
encapsulated in existing transports. The presence of NSH is
indicated via protocol type or other indicator in the outer
encapsulation.
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6. Fragmentation Considerations
NSH and the associated transport header are "added" to the
encapsulated packet/frame. This additional information increases the
size of the packet. In order to ensure proper forwarding of NSH
packets, several options for handling fragmentation and re-assembly
exist:
As discussed in [encap-considerations], within an administrative
domain, an operator can ensure that the underlay MTU is sufficient to
carry SFC traffic without requiring fragmentation.
However, there will be cases where the underlay MTU is not large
enough to carry the NSH traffic. Since NSH does not provide
fragmentation support at the service plane, the transport/overlay
layer MUST provide the requisite fragmentation handling. Section 9
of [encap-considerations] provides guidance for those scenarios.
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7. Service Path Forwarding with NSH
7.1. SFFs and Overlay Selection
As described above, NSH contains a Service Path Identifier (SPI) and
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.
Rather the SPI provide a level of indirection between the service
path/topology and the network transport. Furthermore, there is no
requirement, or expectation of an SPI being bound to a pre-determined
or static network path.
The Service Index provides an indication of location within a service
path. The combination of SPI and SI provides the identification of a
logical SF and its order within the service plane, and is used to
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
equivalent. In the latter case, the SFF provides load distribution
amongst the collection of SFs as needed.
SI can also serve as a mechanism for loop detection within a service
path since each SF in the path decrements the index; an Service Index
of 0 indicates that a loop occurred and the packet must be discarded.
This indirection -- path ID to overlay -- creates a true service
plane. That is the SFF/SF topology is constructed without impacting
the network topology but more importantly service plane only
participants (i.e. most SFs) need not be part of the network overlay
topology and its associated infrastructure (e.g. control plane,
routing tables, etc.). As mentioned above, an existing overlay
topology may be used provided it offers the requisite connectivity.
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
Classifier). The SFF consults the SPI/ID values to determine the
appropriate overlay transport protocol (several may be used within a
given network) and next hop for the requisite SF. Figure 9 below
depicts an example of a single next-hop SPI/SI to network overlay
network locator mapping.
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+-------------------------------------------------------+
| SPI | SI | Next hop(s) | Transport |
+-------------------------------------------------------+
| 10 | 255 | 192.0.2.1 | VXLAN-gpe |
| 10 | 254 | 198.51.100.10 | GRE |
| 10 | 251 | 198.51.100.15 | GRE |
| 40 | 251 | 198.51.100.15 | GRE |
| 50 | 200 | 01:23:45:67:89:ab | Ethernet |
| 15 | 212 | Null (end of path) | None |
+-------------------------------------------------------+
Figure 9: SFF NSH Mapping Example
Additionally, further indirection is possible: the resolution of the
required SF network locator may be a localized resolution on an SFF,
rather than a service function chain control plane responsibility, as
per figures 10 and 11 below.
Please note: VXLAN-gpe and GRE in the above table refer to
[VXLAN-gpe] and [RFC2784], respectively.
+----------------------------+
| SPI | SI | Next hop(s) |
+----------------------------+
| 10 | 3 | SF2 |
| 245 | 12 | SF34 |
| 40 | 9 | SF9 |
+----------------------------+
Figure 10: NSH to SF Mapping Example
+----------------------------------------+
| SF | Next hop(s) | Transport |
+----------------------------------------|
| SF2 | 192.0.2.2 | VXLAN-gpe |
| SF34| 198.51.100.34 | UDP |
| SF9 | 2001:db8::1 | GRE |
+--------------------------+-------------
=
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Figure 11: SF Locator Mapping Example
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
given SF, essentially a series of weighted (equally or otherwise)
paths to be used (for load distribution, redundancy or policy), see
Figure 12. The metric depicted in Figure 12 is an example to help
illustrated weighing SFs. In a real network, the metric will range
from a simple preference (similar to routing next- hop), to a true
dynamic composite metric based on some service function-centric state
(including load, sessions state, capacity, etc.)
+----------------------------------+
| SPI | SI | NH | Metric |
+----------------------------------+
| 10 | 3 | 203.0.113.1 | 1 |
| | | 203.0.113.2 | 1 |
| | | | |
| 20 | 12 | 192.0.2.1 | 1 |
| | | 203.0.113.4 | 1 |
| | | | |
| 30 | 7 | 192.0.2.10 | 10 |
| | | 198.51.100.1| 5 |
+----------------------------------+
(encapsulation type omitted for formatting)
Figure 12: NSH Weighted Service Path
7.2. Mapping NSH to Network Transport
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.
Furthermore, the SPI to overlay mapping occurs at each SFF
independently. Any combination of topology selection is possible.
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
existing) overlay provided the requisite connectivity requirements
are satisfied.
Examples of mapping for a topology:
1. Next SF is located at SFFb with locator 2001:db8::1
SFFa mapping: SPI=10 --> VXLAN-gpe, dst-ip: 2001:db8::1
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2. Next SF is located at SFFc with multiple network locators for
load distribution purposes:
SFFb mapping: SPI=10 --> VXLAN-gpe, dst_ip:203.0.113.1,
203.0.113.2, 203.0.113.3, equal cost
3. Next SF is located at SFFd with two paths from SFFc, one for
redundancy:
SFFc mapping: SPI=10 --> VXLAN-gpe, dst_ip:192.0.2.10 cost=10,
203.0.113.10, cost=20
In the above example, each SFF makes an independent decision about
the network overlay path and policy for that path. In other words,
there is no a priori mandate about how to forward packets in the
network (only the order of services that must be traversed).
The network operator retains the ability to engineer the network
paths as required. For example, the overlay path between SFFs may
utilize traffic engineering, QoS marking, or ECMP, without requiring
complex configuration and network protocol support to be extended to
the service path explicitly. In other words, the network operates as
expected, and evolves as required, as does the service plane.
7.3. Service Plane Visibility
The SPI and SI serve an important function for visibility into the
service topology. An operator can determine what service path a
packet is "on", and its location within that path simply by viewing
the NSH information (packet capture, IPFIX, etc.). The information
can be used for service scheduling and placement decisions,
troubleshooting and compliance verification.
7.4. Service Graphs
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
collection of service function paths, with the interconnection
provided by classifiers (in-service path, non-initial re-
classification). These internal re-classifiers examine the packet 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
new NSH with new values is implementation specific) to reflect the
"result" of the classification. These classifiers may also of course
modify the metadata associated with the packet.
RFC7665, section 2.1 describes Service Graphs in detail.
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8. Policy Enforcement with NSH
8.1. NSH Metadata and Policy Enforcement
As described in Section 3, NSH provides the ability to carry metadata
along a service path. This metadata may be derived from several
sources, common examples include:
Network nodes/devices: Information provided by network nodes can
indicate network-centric information (such as VRF or tenant) that
may be used by service functions, or conveyed to another network
node post service path egress.
External (to the network) systems: External systems, such as
orchestration systems, often contain information that is valuable
for service function policy decisions. In most cases, this
information cannot be deduced by network nodes. For example, a
cloud orchestration platform placing workloads "knows" what
application is being instantiated and can communicate this
information to all NSH nodes via metadata carried in the context
header(s).
Service Functions: A classifier co-resident with Service Functions
often perform very detailed and valuable classification. In some
cases they may terminate, and be able to inspect encrypted
traffic.
Regardless of the source, metadata reflects the "result" of
classification. The granularity of classification may vary. For
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
able to inspect application information. Regardless of granularity,
the classification information can be represented in NSH.
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
local decisions and policy enforcement. The following two examples
highlight the relationship between metadata and policy:
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+-------+ +-------+ +-------+
| SFF )------->( SFF |------->| SFF |
+---^---+ +---|---+ +---|---+
,-|-. ,-|-. ,-|-.
/ \ / \ / \
( Class ) SF1 ) ( SF2 )
\ ify / \ / \ /
`---' `---' `---'
5-tuple: Permit Inspect
Tenant A Tenant A AppY
AppY
Figure 13: Metadata and Policy
+-----+ +-----+ +-----+
| SFF |---------> | SFF |----------> | SFF |
+--+--+ +--+--+ +--+--+
^ | |
,-+-. ,-+-. ,-+-.
/ \ / \ / \
( Class ) ( SF1 ) ( SF2 )
\ ify / \ / \ /
`-+-' `---' `---'
| Permit Deny AppZ
+---+---+ employees
| |
+-------+
external
system:
Employee
AppZ
Figure 14: External Metadata and Policy
In both of the examples above, the service functions perform policy
decisions based on the result of the initial classification: the SFs
did not need to perform re-classification, rather they rely on a
antecedent classification for local policy enforcement.
Depending on the information carried in the metadata, data privacy
considerations may need to be considered. For example, if the
metadata conveys tenant information, that information may need to be
authenticated and/or encrypted between the originator and the
intended recipients (which may include intended SFs only) . NSH
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itself does not provide privacy functions, rather it relies on the
transport/overlay layer. An operator can select the appropriate
transport to ensure the confidentiality (and other security)
considerations are met.
8.2. Updating/Augmenting Metadata
Post-initial metadata imposition (typically performed during initial
service path determination), metadata may be augmented or updated:
1. Metadata Augmentation: Information may be added to NSH's existing
metadata, as depicted in Figure 15. For example, if the initial
classification returns the tenant information, a secondary
classification (perhaps co-resident with DPI or SLB) may augment
the tenant classification with application information, and
impose that new information in the NSH metadata. The tenant
classification is still valid and present, but additional
information has been added to it.
2. Metadata Update: Subsequent classifiers may update the initial
classification if it is determined to be incorrect or not
descriptive enough. For example, the initial classifier adds
metadata that describes the traffic as "internet" but a security
service function determines that the traffic is really "attack".
Figure 16 illustrates an example of updating metadata.
+-----+ +-----+ +-----+
| SFF |---------> | SFF |----------> | SFF |
+--+--+ +--+--+ +--+--+
^ | |
,---. ,---. ,---.
/ \ / \ / \
( Class ) ( SF1 ) ( SF2 )
\ / \ / \ /
`-+-' `---' `---'
| Inspect Deny
+---+---+ employees employee+
| | Class=AppZ appZ
+-------+
external
system:
Employee
Figure 15: Metadata Augmentation
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+-----+ +-----+ +-----+
| SFF |---------> | SFF |----------> | SFF |
+--+--+ +--+--+ +--+--+
^ | |
,---. ,---. ,---.
/ \ / \ / \
( Class ) ( SF1 ) ( SF2 )
\ / \ / \ /
`---' `---' `---'
5-tuple: Inspect Deny
Tenant A Tenant A attack
--> attack
Figure 16: Metadata Update
8.3. Service Path Identifier and Metadata
Metadata information may influence the service path selection since
the Service Path Identifier and Service Index values can represent
the result of classification. A given SPI and SI can be defined
based on classification results (including metadata classification).
The imposition of the SPI/SI (new or an change of existing) reflect,
as previously described, the new SFP.
This relationship provides the ability to create a dynamic service
plane based on complex classification without requiring each node to
be capable of such classification, or requiring a coupling to the
network topology. This yields service graph functionality as
described in Section 7.4. Figure 17 illustrates an example of this
behavior.
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+-----+ +-----+ +-----+
| SFF |---------> | SFF |------+---> | SFF |
+--+--+ +--+--+ | +--+--+
| | | |
,---. ,---. | ,---.
/ \ / SF1 \ | / \
( SCL ) ( + ) | ( SF2 )
\ / \SCL2 / | \ /
`---' `---' +-----+ `---'
5-tuple: Inspect | SFF | Original
Tenant A Tenant A +--+--+ next SF
--> DoS |
V
,-+-.
/ \
( SF10 )
\ /
`---'
DoS
"Scrubber"
Figure 17: Path ID and Metadata
Specific algorithms for mapping metadata to an SPI are outside the
scope of this document.
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9. Security Considerations
As with many other protocols, NSH data can be spoofed or otherwise
modified. As noted in the descriptive text in [sfc-security-
requirements], in many deployments, NSH will be used in a controlled
environment, with trusted devices (e.g. a data center) thus
mitigating the risk of unauthorized header manipulation. As noted
there, far fewer protection mechanisms are needed in these
environments, which are the primary design target of NSH.
NSH is always encapsulated in a transport protocol and therefore,
when required, existing security protocols that provide authenticity
(e.g. [ [RFC6071]) can be used between SFF or even to SF. Similarly
if confidentiality is required, existing encryption protocols can be
used in conjunction with encapsulated NSH.
Further, existing best practices, such as [RFC2827] should be
deployed at the network layer to ensure that traffic entering the
service path is indeed "valid". [encap-considerations] provides
additional transport encapsulation considerations.
NSH metadata authenticity and confidentiality must be considered as
well. In order to protect the metadata, an operator can leverage the
aforementioned mechanisms provided the transport layer, authenticity
and/or confidentiality. An operator MUST carefully select the
transport/underlay services to ensure end to end security services,
when those are sought after. For example, if RFC6071 is used, the
operator MUST ensure it can be supported by the transport/underlay of
all relevant network segments as well as SFF and SFs. Further, as
described in [section 8.1], operators can and should use indirect
identification for personally identifying information, thus
significantly mitigating the risk of privacy violation.
Further, the extensibility of MD Type 2 to add information to
packets, and where needed to mark that data as critical, allows for
attaching signatures or even encryption keying information to the NSH
header in the future. Based on the learnings from the work on [nsh-
sec], it appears likely that this can provide any needed NSH-specific
security mechanisms in the future.
Lastly, SF security, although out of scope of this document, should
be considered, particularly if an SF needs to access, authenticate or
update NSH metadata.
Further security considerations are discussed in [nsh-sec].
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10. Contributors
This WG document originated as draft-quinn-sfc-nsh and had the
following co-authors and contributors. The editors of this document
would like to thank and recognize them and their contributions.
These co-authors and contributors provided invaluable concepts and
content for this document's creation.
Surendra Kumar
Cisco Systems
smkumar@cisco.com
Michael Smith
Cisco Systems
michsmit@cisco.com
Jim Guichard
Cisco Systems
jguichar@cisco.com
Rex Fernando
Cisco Systems
Email: rex@cisco.com
Navindra Yadav
Cisco Systems
Email: nyadav@cisco.com
Wim Henderickx
Alcatel-Lucent
wim.henderickx@alcatel-lucent.com
Andrew Dolganow
Alcaltel-Lucent
Email: andrew.dolganow@alcatel-lucent.com
Praveen Muley
Alcaltel-Lucent
Email: praveen.muley@alcatel-lucent.com
Tom Nadeau
Brocade
tnadeau@lucidvision.com
Puneet Agarwal
puneet@acm.org
Rajeev Manur
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Broadcom
rmanur@broadcom.com
Abhishek Chauhan
Citrix
Abhishek.Chauhan@citrix.com
Joel Halpern
Ericsson
joel.halpern@ericsson.com
Sumandra Majee
F5
S.Majee@f5.com
David Melman
Marvell
davidme@marvell.com
Pankaj Garg
Microsoft
pankajg@microsoft.com
Brad McConnell
Rackspace
bmcconne@rackspace.com
Chris Wright
Red Hat Inc.
chrisw@redhat.com
Kevin Glavin
Riverbed
kevin.glavin@riverbed.com
Hong (Cathy) Zhang
Huawei US R&D
cathy.h.zhang@huawei.com
Louis Fourie
Huawei US R&D
louis.fourie@huawei.com
Ron Parker
Affirmed Networks
ron_parker@affirmednetworks.com
Myo Zarny
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Goldman Sachs
myo.zarny@gs.com
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11. Acknowledgments
The authors would like to thank Sunil Vallamkonda, Nagaraj Bagepalli,
Abhijit Patra, Peter Bosch, Darrel Lewis, Pritesh Kothari, Tal
Mizrahi and Ken Gray for their detailed review, comments and
contributions.
A special thank you goes to David Ward and Tom Edsall for their
guidance and feedback.
Additionally the authors would like to thank Carlos Pignataro and
Larry Kreeger for their invaluable ideas and contributions which are
reflected throughout this document.
Loa Andersson provided a thorough review and valuable comments, we
thank him for that.
Lastly, Reinaldo Penno deserves a particular thank you for his
architecture and implementation work that helped guide the protocol
concepts and design.
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12. IANA Considerations
12.1. NSH EtherType
An IEEE EtherType, 0x894F, has been allocated for NSH.
12.2. Network Service Header (NSH) Parameters
IANA is requested to create a new "Network Service Header (NSH)
Parameters" registry. The following sub-sections request new
registries within the "Network Service Header (NSH) Parameters "
registry.
12.2.1. NSH Base Header Reserved Bits
There are ten bits at the beginning of the NSH Base Header. New bits
are assigned via Standards Action [RFC5226].
Bits 0-1 - Version
Bit 2 - OAM (O bit)
Bit 3 - Critical TLV (C bit)
Bits 4-9 - Reserved
12.2.2. NSH Version
IANA is requested to setup a registry of "NSH Version". New values
are assigned via Standards Action [RFC5226].
Version 00: This protocol version. This document.
Version 01: Reserved. This document.
Version 10: Unassigned.
Version 11: Unassigned.
12.2.3. MD Type Registry
IANA is requested to set up a registry of "MD Types". These are
8-bit values. MD Type values 0, 1, 2, 254, and 255 are specified in
this document. Registry entries are assigned by using the "IETF
Review" policy defined in RFC 5226 [RFC5226].
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+---------+--------------+---------------+
| MD Type | Description | Reference |
+---------+--------------+---------------+
| 0 | Reserved | This document |
| | | |
| 1 | NSH | This document |
| | | |
| 2 | NSH | This document |
| | | |
| 3..253 | Unassigned | |
| | | |
| 254 | Experiment 1 | This document |
| | | |
| 255 | Experiment 2 | This document |
+---------+--------------+---------------+
Table 1
12.2.4. MD Class Registry
IANA is requested to set up a registry of "MD Class". These are 16-
bit values. MD Classes defined by this document are assigned as
follows:
0x0000 to 0x01ff: IETF Review
0x0200 to 0xfff5: Expert Review
0xfff6 to 0xfffe: Experimental
0xffff: Reserved
12.2.5. NSH Base Header Next Protocol
IANA is requested to set up a registry of "Next Protocol". These are
8-bit values. Next Protocol values 0, 1, 2, 3, 4 and 5 are defined
in this draft. New values are assigned via Standards Action
[RFC5226].
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+---------------+--------------+---------------+
| Next Protocol | Description | Reference |
+---------------+--------------+---------------+
| 0 | Reserved | This document |
| | | |
| 1 | IPv4 | This document |
| | | |
| 2 | IPv6 | This document |
| | | |
| 3 | Ethernet | This document |
| | | |
| 4 | NSH | This document |
| | | |
| 5 | MPLS | This document |
| | | |
| 6..253 | Unassigned | |
| | | |
| 254 | Experiment 1 | This document |
| | | |
| 255 | Experiment 2 | This document |
+---------------+--------------+---------------+
Table 2
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13. References
13.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/
RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 5226,
DOI 10.17487/RFC5226, May 2008,
<http://www.rfc-editor.org/info/rfc5226>.
13.2. Informative References
[RFC2784] Farinacci, D., Li, T., Hanks, S., Meyer, D., and P.
Traina, "Generic Routing Encapsulation (GRE)", RFC 2784,
DOI 10.17487/RFC2784, March 2000,
<http://www.rfc-editor.org/info/rfc2784>.
[RFC2827] Ferguson, P. and D. Senie, "Network Ingress Filtering:
Defeating Denial of Service Attacks which employ IP Source
Address Spoofing", BCP 38, RFC 2827, DOI 10.17487/RFC2827,
May 2000, <http://www.rfc-editor.org/info/rfc2827>.
[RFC6071] Frankel, S. and S. Krishnan, "IP Security (IPsec) and
Internet Key Exchange (IKE) Document Roadmap", RFC 6071,
DOI 10.17487/RFC6071, February 2011,
<http://www.rfc-editor.org/info/rfc6071>.
[RFC7325] Villamizar, C., Ed., Kompella, K., Amante, S., Malis, A.,
and C. Pignataro, "MPLS Forwarding Compliance and
Performance Requirements", RFC 7325, DOI 10.17487/RFC7325,
August 2014, <http://www.rfc-editor.org/info/rfc7325>.
[RFC7498] Quinn, P., Ed. and T. Nadeau, Ed., "Problem Statement for
Service Function Chaining", RFC 7498, DOI 10.17487/
RFC7498, April 2015,
<http://www.rfc-editor.org/info/rfc7498>.
[RFC7665] Halpern, J., Ed. and C. Pignataro, Ed., "Service Function
Chaining (SFC) Architecture", RFC 7665, DOI 10.17487/
RFC7665, October 2015,
<http://www.rfc-editor.org/info/rfc7665>.
[SFC-CP] Boucadair, M., "Service Function Chaining (SFC) Control
Plane Components & Requirements", 2016, <https://
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datatracker.ietf.org/doc/draft-ietf-sfc-control-plane/>.
[VXLAN-gpe]
Quinn, P., Manur, R., Agarwal, P., Kreeger, L., Lewis, D.,
Maino, F., Smith, M., Yong, L., Xu, X., Elzur, U., Garg,
P., and D. Melman, "Generic Protocol Extension for VXLAN",
<https://datatracker.ietf.org/doc/
draft-ietf-nvo3-vxlan-gpe/>.
[broadalloc]
Napper, J., Kumar, S., Muley, P., and W. Hendericks, "NSH
Context Header Allocation -- Mobility", 2016, <https://
datatracker.ietf.org/doc/
draft-napper-sfc-nsh-broadband-allocation/>.
[dcalloc] Guichard, J., Smith, M., and et al., "Network Service
Header (NSH) Context Header Allocation (Data Center)",
2016, <https://datatracker.ietf.org/doc/
draft-guichard-sfc-nsh-dc-allocation/>.
[encap-considerations]
Nordmark, E., Tian, A., Gross, J., Hudson, J., Kreeger,
L., Garg, P., Thaler, P., and T. Herbert, "Encapsulation
Considerations", <https://datatracker.ietf.org/doc/
draft-ietf-rtgwg-dt-encap/>.
[nsh-sec] Reddy, T., Migault, D., Pignataro, C., Quinn, P., and C.
Inacio, "NSH Security and Privacy requirements", 2016, <ht
tps://datatracker.ietf.org/doc/
draft-reddy-sfc-nsh-security-req/>.
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Authors' Addresses
Paul Quinn (editor)
Cisco Systems, Inc.
Email: paulq@cisco.com
Uri Elzur (editor)
Intel
Email: uri.elzur@intel.com
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