Internet DRAFT - draft-chunduri-ospf-operator-defined-tlvs
draft-chunduri-ospf-operator-defined-tlvs
Network Working Group U. Chunduri, Ed.
Internet-Draft Ericsson Inc.
Intended status: Standards Track X. Xu
Expires: July 8, 2016 Huawei
L. Contreras
Telefonica I+D
M. Boucadair, Ed.
France Telecom
L. Jalil
Verizon
January 5, 2016
Using Operator-defined TLVs for Agile Service Deployment
draft-chunduri-ospf-operator-defined-tlvs-02
Abstract
This document proposes a TLV within the body of the OSPF Router
Information (RI) Opaque LSA, called Operator-defined Sub-TLV
Container TLV. Here the term OSPF means both OSPFv2 and OSPFv3.This
attribute is meant to accommodate policy-based and deployment-
specific use cases.
Status of This Memo
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This Internet-Draft will expire on July 8, 2016.
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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
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
2. A Sample Use Case . . . . . . . . . . . . . . . . . . . . . . 3
3. Applicability . . . . . . . . . . . . . . . . . . . . . . . . 4
4. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
5. Operator-defined Sub-TLV Container TLV . . . . . . . . . . . 4
6. Operator-defined Sub-TLV . . . . . . . . . . . . . . . . . . 5
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 7
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
9. Security Considerations . . . . . . . . . . . . . . . . . . . 7
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 7
10.1. Normative References . . . . . . . . . . . . . . . . . . 7
10.2. Informative References . . . . . . . . . . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8
1. Introduction
There are some use cases where OSPF is used for service auto-
discovery by using node administrative tags [I-D.ietf-ospf-node-
admin-tag] . One major benefit of using administrative tags rather
than IANA defined TLVs or sub-TLVs to indicate different services is
to facilitate the rapid deployment of new services without any need
for the standardization of those TLVs or sub-TLVs. However, there
are some special use cases where the service to be advertised has one
or more attributes which need to be advertised as well. In such
case, the administrative tag is not much applicable anymore.
To inherit the benefit of administrative tags (i.e., allowing
operators to use OSPF for service auto-discovery without the need of
any standardization process) while meeting the requirement of
advertising services and their associated attributes, this document
proposes a TLV within the body of the OSPF Router Information (RI)
Opaque LSA, called Operator-defined Sub-TLV Container TLV. With such
TLV, operators could flexibly define one or more sub-TLVs indicating
one or more services and their associated attributes without relying
on any standardization process. This document gives a framework
where operator information can be transparently injected into the
routing domain.
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The characterization of the TLV and its associated sub-SLVs is local
to the each administrative domain. Defining new sub-TLVs is
therefore deployment-specific and policy-based. OSPF here denotes
both OSPFv2 and OSPFv3.
1.1. 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].
2. A Sample Use Case
This section describes a use case example to illustrate the use of
the Operator-defined Sub-TLV Container TLV defined in Section 5. It
shows how operators can deploy services rapidly by advertising
associated attributes. It is out of scope of this section to
identify an exhaustive list of deployment use cases.
In the context of service function chaining ([RFC7665]), advertising
Service Functions and it's attributes will ease automating how
service chains are structured and will help policy decision engines
(typically, a controller) to selectively direct the traffic to
appropriate service function instances according to a set policy
guidelines and/or the information reported in the Operator-defined
Sub-TLV.
Particularly, Service Function nodes implementing various service
functions within the network need to advertise each service function
they are offering, so that a control and/or management entity can
decide which instance to invoke for the delivery of an added- value
service or to react to particular events (such as failure of a
service function instance).
Each service can be identified by a dedicated sub-TLV type while the
associated attributes/identifiers of the service are indicated by the
value part of the corresponding sub-TLV. These identifiers MAY not
be globally unique and MAY not be exposed outside of a given
administrative domain.
The Operator-defined sub-TLV Container TLV could appear multiple
times within a given Router Information (RI) Opaque LSA, when more
than one service function instances needs to be advertised by a given
node based on a local policy.
Advertising service functions and it's attributes also allow a
controller to adjust its policies and react dynamically. Typical
actions would be, to withdraw a service instance from being invoked
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in the context of a service delivery, update load balancing polices,
dynamically activate a backup instance, etc.
The mechanisms, on how service information and attributes are used by
an external controller (for example to steer the traffic) is beyond
the scope of this document.
3. Applicability
This mechanism MUST only be used for local applications or non-
standard commercial applications. If the information injected in
this attribute requires a specific handling from an OSPF speaker
other than reading configuration parameters and encode it as
described in this document, then those MUST NOT be advertised through
this mechanism.
The attribute in this document is operator-defined. As such, it is
the responsibility of the provider to decide which information can be
conveyed as per the pre-defined format specific to the deployment by
means of the operator-defined attributes.
4. Terminology
This memo makes use of the terms defined in [RFC4970].
5. Operator-defined Sub-TLV Container TLV
A new TLV within the body of the OSPFv2 and OSPFv3 RI Opaque LSA,
called Operator-defined Sub-TLV Container TLV is defined to carry one
or more operator-defined sub-TLVs.
The format of the Operator-defined Sub-TLV Container TLV is shown in
Figure 1.
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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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| First Operator-defined Sub-TLV |
o o
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// ... //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Last Operator-defined Sub-TLV |
o o
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: Operator-defined Sub-TLV Container TLV
Type: TBD Section 8
Length: A 16-bit field that indicates the length of the value portion
in octets. It MUST be multiple of 4 octets dependent on the number
of Operator-defined Sub-TLVs advertised.
Value: Contains one or more nested TLV triplets of operator-defined
sub-TLVs as defined in Section 6.
There can be more than one TLV of these possible and the flooding
scope of this TLV depends on the application. Being part of the RI
Opaque LSA, the Operator-defined sub-TLV Container TLV inherits
applicability as well as restrictions as specified in Section 3 of
[RFC4970].
6. Operator-defined Sub-TLV
The operator-defined sub-TLV has the following structure and can be
part of the Container TLV as defined in Section 5 within the body of
the OSPF RI LSA.
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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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Attribute Length | Attribute Value (variable) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// ... //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Attribute Length | Attribute Value (variable) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: Operator-defined Sub-TLV
Type: Per Operator/Local Policy.
Length: A 16-bit field that indicates the length of the value portion
in octets and will be padded/formatted as described in Section 2.1 of
[RFC4970].
Value: Represents the associated attribute of the service or Type
defined locally (i.e., within a single administrative domain). The
Value field contains one or more {Attribute-Len, Attribute-value}
tuple. Attribute Length is of 2 bytes, for fixed formatting and
Attribute value as represented by attribute length. All multi byte
attribute values MUST be encoded in Network Byte Order (NBO). If
multiple fixed length values have to be represented, those SHOULD be
represented with multiple {Attribute-Len, Attribute-value} tuples.
The meaning of the operator-defined sub-TLV is totally opaque to OSPF
and is defined by the network local policy and is controlled via
configuration. The application that needs to consume the data
defined is likely to implement some validation checks.
Routers advertising the operator-defined sub-TLV are configured to do
so without knowing (or even explicitly supporting) functionality
implied by the sub-TLV.
How a receiving node communicates the operator-defined sub-TLVs with
the policy manager is outside the scope of this document.
The operator-defined TLV is formatted as described in Section 2.1 of
[RFC4970]. However, the code points of operator-defined sub-TLVs as
defined above are allocated by operators themselves, specific to the
deployment rather than IANA. Furthermore, the semantics of the
operator-defined sub-TLV order has no meaning. That is, there is no
implied meaning to the ordering of the operator-defined sub-TLV that
indicates a certain operation or set of operations that need to be
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performed based on the ordering. The ordering of operator-defined
sub-TLVs and the interpretation of the operator-defined sub-TLV is
deployment-specific. Routers can be configured with local policies
if the order of sub-TLV must be preserved. How a router is
configured with additional instructions (such as order preservation)
is implementation-specific.
It is reasonable that non-routing information should be advertise in
a non-routing instance of OSPF as defined in [I-D.ietf-ospf-
transport-instance] so as to minimize the impact on the operation of
routing. However, since the information contained in the self-
defined sub-TLV may be related to the routing, whether or not using a
non-routing instance to flood the self-defined sub-TLVs should be
determined by operators according to the information to be conveyed
by the self-defined sub-TLV.
7. Acknowledgements
Authors would like to thank Acee Lindem for reviewing and providing
suggestions on the initial version of the document. Also thankful to
Anton Smirnov, Peter Psenak, Chris Bowers and Les Ginsberg for their
review and comments.
8. IANA Considerations
This document includes a request to IANA to allocate a TLV type code
for the new RI LSA TLV proposed in Section 5 of this document from
OSPF Router Information (RI) TLVs Registry defined by [RFC4970].
9. Security Considerations
As Operator Defined TLV specified in this draft is part of RI LSA,
this document does not introduce any new security risk other than
what is specified by [RFC4970]. Security considerations for the base
OSPF protocol are covered in [RFC2328] and [RFC5340].
10. References
10.1. 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>.
[RFC2328] Moy, J., "OSPF Version 2", STD 54, RFC 2328,
DOI 10.17487/RFC2328, April 1998,
<http://www.rfc-editor.org/info/rfc2328>.
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[RFC4970] Lindem, A., Ed., Shen, N., Vasseur, JP., Aggarwal, R., and
S. Shaffer, "Extensions to OSPF for Advertising Optional
Router Capabilities", RFC 4970, DOI 10.17487/RFC4970, July
2007, <http://www.rfc-editor.org/info/rfc4970>.
[RFC5340] Coltun, R., Ferguson, D., Moy, J., and A. Lindem, "OSPF
for IPv6", RFC 5340, DOI 10.17487/RFC5340, July 2008,
<http://www.rfc-editor.org/info/rfc5340>.
10.2. Informative References
[I-D.ietf-ospf-node-admin-tag]
Hegde, S., Raghuveer, H., Gredler, H., Shakir, R.,
Smirnov, A., Li, Z., and B. Decraene, "Advertising per-
node administrative tags in OSPF", draft-ietf-ospf-node-
admin-tag-02 (work in progress), June 2015.
[I-D.ietf-ospf-transport-instance]
Lindem, A., Roy, A., and S. Mirtorabi, "OSPF Transport
Instance Extensions", draft-ietf-ospf-transport-
instance-11 (work in progress), June 2014.
[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>.
Authors' Addresses
Uma Chunduri (editor)
Ericsson Inc.
300 Holger Way,
San Jose, California 95134
USA
Phone: 408 750-5678
Email: uma.chunduri@ericsson.com
Xiaohu Xu
Huawei
Email: xuxiaohu@huawei.com
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Luis M. Contreras
Telefonica I+D
Ronda de la Comunicacion, s/n
Sur-3 building, 3rd floor
Madrid 28050
Spain
Email: luismiguel.contrerasmurillo@telefonica.com
URI: http://people.tid.es/LuisM.Contreras/
Mohamed Boucadair (editor)
France Telecom
Rennes 35000
France
Email: mohamed.boucadair@orange.com
Luay Jalil
Verizon
400 International Parkway
Richardson, Tx 75081
USA
Email: luay.jalil@verizon.com
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