draft-ietf-sfc-nsh-22.txt   draft-ietf-sfc-nsh-23.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: March 26, 2018 Intel Expires: March 26, 2018 Intel
C. Pignataro, Ed. C. Pignataro, Ed.
Cisco Cisco
September 22, 2017 September 22, 2017
Network Service Header (NSH) Network Service Header (NSH)
draft-ietf-sfc-nsh-22 draft-ietf-sfc-nsh-23
Abstract Abstract
This document describes a Network Service Header (NSH) imposed on This document describes a Network Service Header (NSH) imposed on
packets or frames to realize service function paths. The NSH also packets or frames to realize service function paths. The NSH also
provides a mechanism for metadata exchange along the instantiated provides a mechanism for metadata exchange along the instantiated
service paths. The NSH is the SFC encapsulation required to support service paths. The NSH is the SFC encapsulation required to support
the Service Function Chaining (SFC) architecture (defined in the Service Function Chaining (SFC) architecture (defined in
RFC7665). RFC7665).
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10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 28 10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 28
11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 28 11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 28
11.1. NSH EtherType . . . . . . . . . . . . . . . . . . . . . 29 11.1. NSH EtherType . . . . . . . . . . . . . . . . . . . . . 29
11.2. Network Service Header (NSH) Parameters . . . . . . . . 29 11.2. Network Service Header (NSH) Parameters . . . . . . . . 29
11.2.1. NSH Base Header Bits . . . . . . . . . . . . . . . . 29 11.2.1. NSH Base Header Bits . . . . . . . . . . . . . . . . 29
11.2.2. NSH Version . . . . . . . . . . . . . . . . . . . . 29 11.2.2. NSH Version . . . . . . . . . . . . . . . . . . . . 29
11.2.3. MD Type Registry . . . . . . . . . . . . . . . . . . 29 11.2.3. MD Type Registry . . . . . . . . . . . . . . . . . . 29
11.2.4. MD Class Registry . . . . . . . . . . . . . . . . . 30 11.2.4. MD Class Registry . . . . . . . . . . . . . . . . . 30
11.2.5. NSH Base Header Next Protocol . . . . . . . . . . . 31 11.2.5. NSH Base Header Next Protocol . . . . . . . . . . . 31
11.2.6. New IETF Assigned Optional Variable Length Metadata 11.2.6. New IETF Assigned Optional Variable Length Metadata
Type Registry . . . . . . . . . . . . . . . . . . . 31 Type Registry . . . . . . . . . . . . . . . . . . . 32
12. References . . . . . . . . . . . . . . . . . . . . . . . . . 32 12. References . . . . . . . . . . . . . . . . . . . . . . . . . 32
12.1. Normative References . . . . . . . . . . . . . . . . . . 32 12.1. Normative References . . . . . . . . . . . . . . . . . . 32
12.2. Informative References . . . . . . . . . . . . . . . . . 32 12.2. Informative References . . . . . . . . . . . . . . . . . 32
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 34 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 34
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
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encapsulated packet. It is therefore the last node operating on encapsulated packet. It is therefore the last node operating on
the service header. the service header.
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 of 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
replace the existing NSH with a new NSH with the Base Header and replace the existing NSH with a new NSH with the Base Header and
Service Path Header reflecting the new service path information Service Path Header reflecting the new service path information
and MUST set the initial SI. Metadata MAY be preserved in the and MUST set the initial SI. The O bit, as well as unassigned
new NSH. flags, MUST be copied transparently from the old NSH to a new
NSH. Metadata MAY be 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 the NSH: SFs MUST decrement the service index by one. If 3. Update the NSH: SFs MUST decrement the service index by one. If
an SFF receives a packet with an SPI and SI that do not 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, correspond to a valid next hop in a valid Service Function Path,
that packet MUST be dropped by the SFF. that packet MUST be dropped by the SFF.
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| | | | | | | |
| 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
Expert Review requests MUST include a single code point per request. Expert Review requests MUST include a single code point per request.
Designated Experts evaluating new allocation requests from this Designated Experts evaluating new allocation requests from this
registry should consider the potential scarcity of code points for an registry should consider the potential scarcity of code points for an
8-bit value, and check both for duplications as well as availability 8-bit value, and check both for duplications as well as availability
of documentation. of documentation. If the actual assignment of the Next Protocol
field allocation exceeds half of the range, that is when there are
128 unassigned values, IANA needs to alert the IESG. At this point,
a new more strict allocation policy SHOULD be considered.
11.2.6. New IETF Assigned Optional Variable Length Metadata Type 11.2.6. New IETF Assigned Optional Variable Length Metadata Type
Registry 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 Optional Variable Length Metadata Type Registry", as Assigned Optional Variable Length Metadata Type Registry", as
specified in Section 2.5.1. specified in Section 2.5.1.
The type values are assigned via Standards Action [RFC8126]. The type values are assigned via Standards Action [RFC8126].
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