Network Service Header
draft-quinn-sfc-nsh-03
The information below is for an old version of the document.
| Document | Type |
This is an older version of an Internet-Draft whose latest revision state is "Replaced".
|
|
|---|---|---|---|
| Authors | Paul Quinn , Jim Guichard , Rex Fernando , Surendra Kumar , Michael Smith , Navindra Yadav, Puneet Agarwal , Rajeev Manur , Abhishek Chauhan , Uri Elzur , Pankaj Garg , Brad McConnell , Chris Wright | ||
| Last updated | 2014-07-03 | ||
| Replaces | draft-quinn-nsh | ||
| Replaced by | draft-ietf-sfc-nsh, draft-ietf-sfc-nsh, RFC 8300 | ||
| RFC stream | (None) | ||
| Formats | |||
| Stream | Stream state | (No stream defined) | |
| Consensus boilerplate | Unknown | ||
| RFC Editor Note | (None) | ||
| IESG | IESG state | I-D Exists | |
| Telechat date | (None) | ||
| Responsible AD | (None) | ||
| Send notices to | (None) |
draft-quinn-sfc-nsh-03
Network Working Group P. Quinn
Internet-Draft J. Guichard
Intended status: Standards Track R. Fernando
Expires: January 4, 2015 S. Kumar
M. Smith
N. Yadav
Cisco Systems, Inc.
P. Agarwal
R. Manur
Broadcom
A. Chauhan
Citrix
U. Elzur
Intel
P. Garg
Microsoft
B. McConnell
Rackspace
C. Wright
Red Hat Inc.
July 3, 2014
Network Service Header
draft-quinn-sfc-nsh-03.txt
Abstract
This draft describes a Network Service Header (NSH) inserted onto
encapsulated packets or frames to realize service function paths.
NSH also provides a mechanism for metadata exchange along the
instantiated service path.
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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 January 4, 2015.
Copyright Notice
Copyright (c) 2014 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
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
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Table of Contents
1. Requirements Language . . . . . . . . . . . . . . . . . . . . 2
2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.1. Definition of Terms . . . . . . . . . . . . . . . . . . . 4
2.2. Problem Space . . . . . . . . . . . . . . . . . . . . . . 6
3. Network Service Header Overview . . . . . . . . . . . . . . . 8
4. NSH Base Header . . . . . . . . . . . . . . . . . . . . . . . 9
5. Service Path Header . . . . . . . . . . . . . . . . . . . . . 11
6. Mandatory Context Headers . . . . . . . . . . . . . . . . . . 12
6.1. Context Header Allocation Guidelines . . . . . . . . . . . 12
7. Optional Variable Length Metadata . . . . . . . . . . . . . . 14
8. NSH Actions . . . . . . . . . . . . . . . . . . . . . . . . . 16
9. NSH Encapsulation . . . . . . . . . . . . . . . . . . . . . . 17
10. NSH Usage . . . . . . . . . . . . . . . . . . . . . . . . . . 18
11. NSH Proxy Nodes . . . . . . . . . . . . . . . . . . . . . . . 19
12. NSH Encapsulation Examples . . . . . . . . . . . . . . . . . . 20
12.1. GRE + NSH . . . . . . . . . . . . . . . . . . . . . . . . 20
12.2. VXLAN-gpe + NSH . . . . . . . . . . . . . . . . . . . . . 20
13. Security Considerations . . . . . . . . . . . . . . . . . . . 21
14. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 22
15. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 23
15.1. NSH EtherType . . . . . . . . . . . . . . . . . . . . . . 23
15.2. Network Service Header (NSH) Parameters . . . . . . . . . 23
15.2.1. NSH Base Header Reserved Bits . . . . . . . . . . . . 23
15.2.2. MD Type Registry . . . . . . . . . . . . . . . . . . 23
15.2.3. TLV Class Registry . . . . . . . . . . . . . . . . . 24
15.2.4. NSH Base Header Next Protocol . . . . . . . . . . . . 24
16. References . . . . . . . . . . . . . . . . . . . . . . . . . . 25
16.1. Normative References . . . . . . . . . . . . . . . . . . . 25
16.2. Informative References . . . . . . . . . . . . . . . . . . 25
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 26
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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.
The current service function deployment models are 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 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 are necessary.
The approach taken by NSH is composed of the following elements:
1. Service path identification
2. Mandatory fixed size, transport independent per-packet/frame
service metadata.
3. Optional variable 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.
The SFC Architecture document [SFC-arch] 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.
2.1. Definition of Terms
Classification: Locally instantiated policy and customer/network/
service profile matching of traffic flows for identification of
appropriate outbound forwarding actions.
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SFC Network Forwarder (NF): SFC network forwarders provide network
connectivity for service functions forwarders and service
functions. SFC network forwarders participate in the network
overlay used for service function chaining as well as in the SFC
encapsulation.
Service Function Forwarder (SFF): A service function forwarder is
responsible for delivering traffic received from the NF to one or
more connected service functions, and from service functions to
the NF.
Service Function (SF): A function that is responsible for specific
treatment of received packets. A service function can act at the
network layer or other OSI layers. A service function can be a
virtual instance or be embedded in a physical network element.
One of multiple service functions can be embedded in the same
network element. Multiple instances of the service function can
be enabled in the same administrative domain.
Service Node (SN): Physical or virtual element that hosts one or
more service functions and has one or more network locators
associated with it for reachability and service delivery.
Service Function Chain (SFC): A service Function chain defines an
ordered set of service functions that must be applied to packets
and/or frames selected as a result of classification. The implied
order may not be a linear progression as the architecture allows
for nodes that copy to more than one branch. The term service
chain is often used as shorthand for service function chain.
Service Function Path (SFP): The instantiation of a SFC in the
network. Packets follow a service function path from a classifier
through the requisite service functions
Network Node/Element: Device that forwards packets or frames based
on outer header information. In most cases is not aware of the
presence of NSH.
Network Overlay: Logical network built on top of existing network
(the underlay). Packets are encapsulated or tunneled to create
the overlay network topology.
Network Service Header: Data plane header added to frames/packets.
The header contains information required for service chaining, as
well as metadata added and consumed by network nodes and service
elements.
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Service Classifier: Function that performs classification and
imposes an NSH. Creates a service path. Non-initial (i.e.
subsequent) classification can occur as needed and can alter, or
create a new service path.
Service Hop: NSH aware node, akin to an IP hop but in the service
overlay.
Service Path Segment: A segment of a service path overlay.
NSH Proxy: Acts as a gateway: removes and inserts NSH on behalf of a
service function that is not NSH aware.
2.2. Problem Space
Network Service Header (NSH) addresses several limitations associated
with service function deployments today.
1. Topological Dependencies: Network service deployments are often
coupled to network topology. Such dependency imposes constraints
on the service delivery, potentially inhibiting the network
operator from optimally utilizing service resources, and reduces
the flexibility. This limits scale, capacity, and redundancy
across network resources.
2. Service Chain Construction: Service function chains today are
most typically built through manual configuration processes.
These are slow and error prone. With the advent of newer service
deployment models the control/management planes provide not only
connectivity state, but will also be increasingly utilized for
the creation of network services. Such a control/management
planes could be centralized, or be distributed.
3. Application of Service Policy: Service functions rely on topology
information such as VLANs or packet (re) classification to
determine service policy selection, i.e. the service function
specific action taken. Topology information is increasingly less
viable due to scaling, tenancy and complexity reasons. The
topological information is often stale, providing the operator
with inaccurate placement that can result in suboptimal resource
utilization. Furthermore topology-centric information often does
not convey adequate information to the service functions, forcing
functions to individually perform more granular classification.
4. Per-Service (re)Classification: Classification occurs at each
service function independent from previously applied service
functions. More importantly, the classification functionality
often differs per service function and service functions may not
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leverage the results from other service functions.
5. Common Header Format: Various proprietary methods are used to
share metadata and create service paths. An open header provides
a common format for all network and service devices.
6. Limited End-to-End Service Visibility: Troubleshooting service
related issues is a complex process that involve both network-
specific and service-specific expertise. This is especially the
case when service function chains span multiple DCs, or across
administrative boundaries. Furthermore, the physical and virtual
environments (network and service), can be highly divergent in
terms of topology and that topological variance adds to these
challenges.
7. Transport Dependence: Service functions can and will be deployed
in networks with a range of transports, including under and
overlays. The coupling of service functions to topology requires
service functions to support many transports or for a transport
gateway function to be present.
Please see the Service Function Chaining Problem Statement [SFC-PS]
for a more detailed analysis of service function deployment problem
areas.
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3. Network Service Header Overview
A Network Service Header (NSH) contains metadata and service path
information that is added to a packet or frame and used to create a
service plane. The packets and the NSH are then encapsulated in an
outer header for transport.
The service header is added by a service classification function - a
device or application - that determines which packets require
servicing, and correspondingly which service path to follow to apply
the appropriate service.
A NSH is composed of a 4-byte base header, a 4-byte service path
header, four mandatory 4 byte context headers, and optional variable
length 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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Mandatory Context Header |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Mandatory Context Header |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Mandatory Context Header |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Mandatory Context Header |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Optional Variable Length 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 path.
Mandatory context headers: carry opaque metadata.
Optional variable length context headers: carry variable length
encoded information.
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4. 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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Version: 2 bits
Flags: 8 bits
Length: 6 bits
Metadata Type: 8 bits
Next protocol (NP): 8 bits
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.
O bit: Indicates that this packet is an operations and management
(OAM) packet. SFF and SFs nodes MUST examine the payload and take
appropriate action (e.g. return status information).
OAM message specifics and handling details are outside the scope of
this document.
C bit: Indicates that a critical metadata TLV is present (see section
7). 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. The C bit MUST be set
to 1 if one or more critical TLVs are present.
All other flag fields are reserved.
Length: total length, in 4 byte words, of the NSH header, including
optional variable TLVs. Length must be equal or greater than 6.
MD Type: indicates the format of NSH beyond the base header and the
type of metadata being carried. This typing is used to describe the
use for the metadata. A new registry will be requested from IANA for
the MD Type. NSH defines one type, type = 0x1 which indicates that
the format of the header is as per this draft.
The format of the base header is invariant, and not described by MD
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Type.
Next Protocol: indicates the protocol type of the original packet. A
new IANA registry will be created for protocol type.
This draft defines the following Next Protocol values:
0x1 : IPv4
0x2 : IPv6
0x3 : Ethernet
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5. 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 ID | Service Index |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Service path ID (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 path selection. An
administrator can use the service path value for reporting and
troubleshooting packets along a specific path.
Service Index (SI): provides location within the service path.
Service index MUST be decremented by service functions or proxy nodes
after performing required services. MAY be used in conjunction with
service path for path selection. Service Index is also valuable when
troubleshooting/reporting service paths. In addition to location
within a path, SI can be used for loop detection.
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6. Mandatory Context Headers
When the base header specifies MD type 1, NSH defines four 4-byte
context headers. These headers must be present and the format is
opaque as depicted in figure 4.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Context data |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4: Context Header
6.1. Context Header Allocation Guidelines
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Network Platform Context |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Network Shared Context |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Service Platform Context |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Service Shared Context |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 5: Context Data Significance
Figure 5, above, and the the following examples of context header
allocation are guidelines that illustrate how various forms of
information can be carried and exchanged via NSH.
Network platform context: provides platform-specific metadata shared
between network nodes. Examples include (but are not limited to)
ingress port information, forwarding context and encapsulation type.
Network shared context: metadata relevant to any network node such as
the result of edge classification. For example, application
information, identity information or tenancy information can be
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shared using this context header.
Service platform context: provides service platform specific metadata
shared between service functions. This context header is analogous
to the network platform context, enabling service platforms to
exchange platform-centric information such as an identifier used for
load balancing decisions.
Service shared context: metadata relevant to, and shared, between
service functions. As with the shared network context,
classification information such as application type can be conveyed
using this context.
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7. Optional Variable Length Metadata
In addition to the required, fixed size context headers, NSH MAY also
contain optional variable length context headers. These header are
formatted as TLVs.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Class | Type |R|R|R| Len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Variable Metadata |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 6: Variable Context Headers
TLV Class: describes the scope of the "Type" field. In some cases,
the TLV Class will identify a specific vendor, in others, the TLV
Class will identify specific standards body allocated types.
Type: the specific type of information being carried, within the
scope of a given TLV Class. Value allocation is the responsibility
of the TLV Class owner.
The most significant bit of the Type field indicates whether the TLV
is mandatory for the receiver to understand/process. This
effectively allocates Type values 0 to 127 for non-critical options
and Type values 128 to 255 for critical options. Figure 7 below
illustrates the placement of the Critical bit within the Type field.
+-+-------+
|C| Type |
+-+-------+
Figure 7: Critical Bit Placement Within the TLV Type Field
Encoding the criticality of the TLV within the Type field is
consistent with IPv6 option types.
If a receiver receives an encapsulated packet containing a TLV with
the Critical bit set in the Type field and it does not understand how
to process the Type, it MUST drop the packet. Transit devices MUST
NOT drop packets based on the setting of this bit.
Reserved bits: three reserved bit are present for future use. The
reserved bits MUST be zero.
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Length: Length of the variable metadata, in 4 byte words.
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8. NSH Actions
Service header aware nodes - service classifiers, SFF, SF and NSH
proxies, have several possible header related actions:
1. Insert or remove service header: These actions can occur at the
start and end respectively of a service path. Packets are
classified, and if determined to require servicing, a service
header imposed. The last node in a service chain, an SF, or an
associated SFF, removes NSH. A service classifier MUST insert a
NSH. At the end of a service function chain, the last node
operating on the service header MUST remove it.
A service function can re-classify data as required and that re-
classification might result in a new service path. If a SF
performs re-classification that results in a change of service
path, it MUST remove the existing NSH and MUST imposes a new NSH
with the base header reflecting the new path.
2. Select service path: The base header provides service chain
information and is used by SFFs to determine correct service path
selection. SFFs MUST use the base header for selecting the next
service in the service path.
3. Update a service header: NSH aware service functions MUST
decrement the service index. A service index = 0 indicates that
a packet MUST be dropped by the SFF performing NSH based
forwarding.
Service functions MAY update context headers if new/updated
context is available.
If an NSH proxy is in use (acting on behalf of a non-aware
service function for NSH actions), then the proxy MUST update
service index and MAY update contexts.
4. Service policy selection: Service function instances derive
policy selection from the service header. Context 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.
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9. 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.
See section 12 for NSH encapsulation examples.
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10. NSH Usage
NSH creates a dedicated service plane, that addresses many of the
limitations highlighted in section 2.2. More specifically, NSH
enables:
1. Topological Independence: Service forwarding occurs within the
service plane, via a network overlay, the underlying network
topology does not require modification. Service functions have
one or more network locators (e.g. IP address), to receive/send
data within the service plane, the NSH header contains an
identifier that is used to uniquely identify a service path and
the services within that path.
2. Service Chaining: 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 analyzer) to verify
(account, ensure correct chaining, provide reports, etc.) the
path specifics of packets being forwarded along a service path.
3. Metadata Sharing: NSH provides a mechanism to carry shared
metadata between network devices and service function, and
between service functions. The semantics of the shared metadata
is communicated via a control plane to participating nodes.
Examples of metadata include classification information used for
policy enforcement and network context for forwarding post
service delivery.
4. Transport Agnostic: NSH is transport independent and can be used
with overlay and underlay forwarding topologies.
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11. NSH Proxy Nodes
In order to support NSH unaware service functions, an NSH proxy is
used. The proxy node removes the NSH header and delivers, to the
service node, the original packet/frame via a local attachment
circuit. Examples of a local attachment circuit include, but are not
limited to: VLANs, IP in IP, GRE, VXLAN. When complete, the service
function returns the packet to the NSH-proxy via the same or
different attachment circuit.
NSH is re-imposed on packets returned to the proxy from the non-NSH
aware service.
Typically, a SFF will act as a NSH-proxy when required.
An NSH proxy MUST perform NSH actions as described in section 7.
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12. NSH Encapsulation Examples
12.1. GRE + NSH
IPv4 Packet:
+----------+--------------------+--------------------+
|L2 header | L3 header, proto=47|GRE header,PT=0x894F|
+----------+--------------------+--------------------+
--------------+----------------+
NSH, PT=0x1 |original packet |
--------------+----------------+
L2 Frame:
+----------+--------------------+--------------------+
|L2 header | L3 header, proto=47|GRE header,PT=0x894F|
+----------+--------------------+--------------------+
---------------+---------------+
NSH, NP=0x3 |original frame |
---------------+---------------+
Figure 8: GRE + NSH
12.2. VXLAN-gpe + NSH
IPv4 Packet:
+----------+--------------------+---------------------+
|L2 header | UDP dst port=TBD |VXLAN-gpe NP=0x4(NSH)|
+----------+--------------------+---------------------+
--------------+----------------+
NSH, NP=0x1 |original packet |
--------------+----------------+
L2 Frame:
+----------+--------------------+---------------------+
|L2 header | UDP dst port=TBD |VXLAN-gpe NP=0x4(NSH)|
+----------+--------------------+---------------------+
---------------+---------------+
NSH,NP=0x3 |original frame |
---------------+---------------+
Figure 9: VXLAN-gpe + NSH
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13. Security Considerations
As with many other protocols, NSH data can be spoofed or otherwise
modified. 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.
NSH is always encapsulated in a transport protocol and therefore,
when required, existing security protocols that provide authenticity
(e.g. RFC 2119 [RFC6071]) can be used.
Similarly if confidentiality is required, existing encryption
protocols can be used in conjunction with encapsulated NSH.
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14. Acknowledgments
The authors would like to thank Nagaraj Bagepalli, Abhijit Patra, Ron
Parker, Peter Bosch, Tom Nadeau, Darrel Lewis, Pritesh Kothari 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 draft.
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15. IANA Considerations
15.1. NSH EtherType
An IEEE EtherType, 0x894F, has been allocated for NSH.
15.2. 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.
15.2.1. 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)
Bits 2-9 - Reserved
15.2.2. MD Type Registry
IANA is requested to set up a registry of "MD Types". These are
8-bit values. MD Type values 0, 1, 254, and 255 are specified in
this document. Registry entries are assigned by using the "IETF
Review" policy defined in RFC 5226 [RFC5226].
+---------+--------------+---------------+
| MD Type | Description | Reference |
+---------+--------------+---------------+
| 0 | Reserved | This document |
| | | |
| 1 | NSH | This document |
| | | |
| 2..253 | Unassigned | |
| | | |
| 254 | Experiment 1 | This document |
| | | |
| 255 | Experiment 2 | This document |
+---------+--------------+---------------+
Table 1
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15.2.3. TLV Class Registry
IANA is requested to set up a registry of "TLV Types". These are 16-
bit values. Registry entries are assigned by using the "IETF Review"
policy defined in RFC 5226 [RFC5226].
15.2.4. 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 and 3 are defined in this
draft. New values are assigned via Standards Action [RFC5226].
+---------------+-------------+---------------+
| Next Protocol | Description | Reference |
+---------------+-------------+---------------+
| 0 | Reserved | This document |
| | | |
| 1 | IPv4 | This document |
| | | |
| 2 | IPv6 | This document |
| | | |
| 3 | Ethernet | This document |
| | | |
| 4..253 | Unassigned | |
+---------------+-------------+---------------+
Table 2
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16. References
16.1. Normative References
[RFC0791] Postel, J., "Internet Protocol", STD 5, RFC 791,
September 1981.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
16.2. Informative References
[RFC2784] Farinacci, D., Li, T., Hanks, S., Meyer, D., and P.
Traina, "Generic Routing Encapsulation (GRE)", RFC 2784,
March 2000.
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 5226,
May 2008.
[RFC6071] Frankel, S. and S. Krishnan, "IP Security (IPsec) and
Internet Key Exchange (IKE) Document Roadmap", RFC 6071,
February 2011.
[SFC-PS] Quinn, P., Ed. and T. Nadeau, Ed., "Service Function
Chaining Problem Statement", 2014, <http://
datatracker.ietf.org/doc/
draft-ietf-sfc-problem-statement/>.
[SFC-arch]
Quinn, P., Ed. and J. Halpern, Ed., "Service Function
Chaining (SFC) Architecture", 2014,
<http://datatracker.ietf.org/doc/draft-quinn-sfc-arch>.
[VXLAN-gpe]
Dutt, D., Quinn, P., Duda, ., Agarwal, P., Kreeger, L.,
Sridhar, T., Bursell, M., and C. Wright, "Generic Protocol
Extension for VXLAN",
<https://datatracker.ietf.org/doc/draft-quinn-vxlan-gpe/>.
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Authors' Addresses
Paul Quinn
Cisco Systems, Inc.
Email: paulq@cisco.com
Jim Guichard
Cisco Systems, Inc.
Email: jguichar@cisco.com
Rex Fernando
Cisco Systems, Inc.
Email: rex@cisco.com
Surendra Kumar
Cisco Systems, Inc.
Email: smkumar@cisco.com
Michael Smith
Cisco Systems, Inc.
Email: michsmit@cisco.com
Navindra Yadav
Cisco Systems, Inc.
Email: nyadav@cisco.com
Puneet Agarwal
Broadcom
Email: pagarwal@broadcom.com
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Rajeev Manur
Broadcom
Email: rmanur@broadcom.com
Abhishek Chauhan
Citrix
Email: Abhishek.Chauhan@citrix.com
Uri Elzur
Intel
Email: uri.elzur@intel.com
Pankaj Garg
Microsoft
Email: Garg.Pankaj@microsoft.com
Brad McConnell
Rackspace
Email: bmcconne@rackspace.com
Chris Wright
Red Hat Inc.
Email: chrisw@redhat.com
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