Internet DRAFT - draft-chunduri-ospf-self-defined-sub-tlvs
draft-chunduri-ospf-self-defined-sub-tlvs
Network Working Group U. Chunduri
Internet-Draft Ericsson Inc.
Intended status: Standards Track X. Xu
Expires: September 10, 2015 Huawei
L. Contreras
Telefonica I+D
M. Boucadair
France Telecom
March 9, 2015
Using Self-defined Sub-TLVs for Agile Service Deployment
draft-chunduri-ospf-self-defined-sub-tlvs-03
Abstract
This document proposes a TLV within the body of the OSPF Router
Information (RI) Opaque LSA, called Self-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 September 10, 2015.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
2. Sample Use Cases . . . . . . . . . . . . . . . . . . . . . . 3
3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
4. Self-defined Sub-TLV Container TLV . . . . . . . . . . . . . 4
5. Self-defined Sub-TLV . . . . . . . . . . . . . . . . . . . . 5
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 6
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
8. Security Considerations . . . . . . . . . . . . . . . . . . . 6
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 6
9.1. Normative References . . . . . . . . . . . . . . . . . . 6
9.2. Informative References . . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7
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 Self-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.
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 denotes both
OSPFv2 and OSPFv3.
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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. Sample Use Cases
There can be several possible use cases and applications for Self-
defined Sub-TLV Container TLV defined in Section 4. This section
provides few examples how operators can deploy services rapidly by
advertising associated attributes. However, the illustrations listed
below are not meant to be restrictive or exhaustive.
o Advertising Service Functions and it's attributes
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 Self-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
the controller to adjust its policies and react dynamically.
Typical actions would be, to withdraw a service instance from
being invoked 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.
o Dissemination of dynamic information
It's possible for operators to disseminate the node local
information like energy efficiency, congestion information,
certain critical node statistics periodically to an external
controller managing the network. How a Controller uses this
information is beyond the scope of this document.
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3. Terminology
This memo makes use of the terms defined in [RFC4970].
4. Self-defined Sub-TLV Container TLV
A new TLV within the body of the OSPFv2 and OSPFv3 RI Opaque LSA,
called Self-defined Sub-TLV Container TLV is defined to carry one or
more self-defined sub-TLVs.
The format of the Self-defined Sub-TLV Container TLV is shown in
Figure 1.
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 Self-defined Sub-TLV |
o o
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// ... //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Last Self-defined Sub-TLV |
o o
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: Self-defined Sub-TLV Container TLV
Type: TBD Section 7
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 Self-defined Sub-TLVs advertised.
Value: Contains one or more nested TLV triplets of self-defined sub-
TLVs as defined in Section 5.
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 Self-defined sub-TLV Container TLV inherits
applicability as well as restrictions as specified in Section 3 of
[RFC4970].
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5. Self-defined Sub-TLV
The self-defined sub-TLV has the following structure and can be part
of the Container TLV as defined in Section 4 within the body of the
OSPF RI LSA.
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: Self-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.
The meaning of the self-defined sub-TLV is totally opaque to OSPF.
Routers advertising the self-defined sub-TLV are configured to do so
without knowing (or even explicitly supporting) functionality implied
by the sub-TLV.
The meaning of a self-defined sub-TLV is defined by the network local
policy and is controlled via configuration.
How a receiving node communicates the self-defined sub-TLVs with the
policy manager is outside the scope of this document.
There is no need for any specification to define any self-defined
sub-TLV. Furthermore, the semantics of the self-defined sub-TLV
order has no meaning. That is, there is no implied meaning to the
ordering of the self-defined sub-TLV that indicates a certain
operation or set of operations that need to be performed based on the
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ordering. The ordering of self-defined sub-TLVs and the
interpretation of the self-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.
6. 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 and Les Ginsberg for their review and
comments.
7. IANA Considerations
This document includes a request to IANA to allocate a TLV type code
for the new RI LSA TLV proposed in Section 4 of this document from
OSPF Router Information (RI) TLVs Registry defined by [RFC4970].
8. Security Considerations
This document does not introduce any new security risk other than
what is specified by [RFC4970].
9. References
9.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC4970] Lindem, A., Shen, N., Vasseur, JP., Aggarwal, R., and S.
Shaffer, "Extensions to OSPF for Advertising Optional
Router Capabilities", RFC 4970, July 2007.
[RFC5838] Lindem, A., Mirtorabi, S., Roy, A., Barnes, M., and R.
Aggarwal, "Support of Address Families in OSPFv3", RFC
5838, April 2010.
9.2. 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-00 (work in progress), October 2014.
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Authors' Addresses
Uma Chunduri
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
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
France Telecom
Rennes 35000
France
Email: mohamed.boucadair@orange.com
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