draft-ietf-ospf-node-admin-tag-02.txt   draft-ietf-ospf-node-admin-tag-03.txt 
Open Shortest Path First IGP S. Hegde Open Shortest Path First IGP S. Hegde
Internet-Draft Juniper Networks, Inc. Internet-Draft Juniper Networks, Inc.
Intended status: Standards Track H. Raghuveer Intended status: Standards Track H. Raghuveer
Expires: December 3, 2015 Expires: February 28, 2016
H. Gredler H. Gredler
Juniper Networks, Inc. Juniper Networks, Inc.
R. Shakir R. Shakir
British Telecom British Telecom
A. Smirnov A. Smirnov
Cisco Systems, Inc. Cisco Systems, Inc.
Z. Li Z. Li
Huawei Technologies Huawei Technologies
B. Decraene B. Decraene
Orange Orange
June 1, 2015 August 27, 2015
Advertising per-node administrative tags in OSPF Advertising per-node administrative tags in OSPF
draft-ietf-ospf-node-admin-tag-02 draft-ietf-ospf-node-admin-tag-03
Abstract Abstract
This document describes an extension to OSPF protocol [RFC2328] to This document describes an extension to OSPF protocol to add an
add an optional operational capability, that allows tagging and optional operational capability, that allows tagging and grouping of
grouping of the nodes in an OSPF domain. This allows simplification, the nodes in an OSPF domain. This allows simplification, ease of
ease of management and control over route and path selection based on management and control over route and path selection based on
configured policies. This document describes an extension to OSPF configured policies. This document describes an extension to OSPF
protocol [RFC2328] to advertise per-node administrative tags. This protocol to advertise per-node administrative tags. This optional
optional operational capability allows to express and act upon operational capability allows to express and act upon locally-defined
locally-defined network policy which considers node properties network policy which considers node properties conveyed by tags.
conveyed by tags. Node tags may be used either by OSPF itself or by Node tags may be used either by OSPF itself or by other applications
other applications consuming information propagated via OSPF. consuming information propagated via OSPF.
This document describes the protocol extensions to disseminate per- This document describes the protocol extensions to disseminate per-
node administrative-tags to the OSPFv2 and OSPFv3 protocol. It node administrative-tags to the OSPFv2 and OSPFv3 protocol. It
provides example use cases of administrative node tags. provides example use cases of administrative node tags.
Requirements Language Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119]. document are to be interpreted as described in RFC 2119 [RFC2119].
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on December 3, 2015. This Internet-Draft will expire on February 28, 2016.
Copyright Notice Copyright Notice
Copyright (c) 2015 IETF Trust and the persons identified as the Copyright (c) 2015 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
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described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Administrative Tag TLV . . . . . . . . . . . . . . . . . . . 3 2. Administrative Tag TLV . . . . . . . . . . . . . . . . . . . 3
3. OSPF per-node administrative tag TLV . . . . . . . . . . . . 3 3. OSPF per-node administrative tag TLV . . . . . . . . . . . . 3
3.1. TLV format . . . . . . . . . . . . . . . . . . . . . . . 3 3.1. TLV format . . . . . . . . . . . . . . . . . . . . . . . 3
3.2. Elements of procedure . . . . . . . . . . . . . . . . . . 4 3.2. Elements of procedure . . . . . . . . . . . . . . . . . . 4
4. Applications . . . . . . . . . . . . . . . . . . . . . . . . 5 4. Applications . . . . . . . . . . . . . . . . . . . . . . . . 5
4.1. Service auto-discovery . . . . . . . . . . . . . . . . . 5 4.1. Service auto-discovery . . . . . . . . . . . . . . . . . 6
4.2. Fast-Rerouting policy . . . . . . . . . . . . . . . . . . 6 4.2. Fast-Rerouting policy . . . . . . . . . . . . . . . . . . 6
4.3. Controlling Remote LFA tunnel termination . . . . . . . . 7 4.3. Controlling Remote LFA tunnel termination . . . . . . . . 7
4.4. Mobile backhaul network service deployment . . . . . . . 7 4.4. Mobile backhaul network service deployment . . . . . . . 7
4.5. Explicit routing policy . . . . . . . . . . . . . . . . . 8 4.5. Explicit routing policy . . . . . . . . . . . . . . . . . 9
5. Security Considerations . . . . . . . . . . . . . . . . . . . 10 5. Security Considerations . . . . . . . . . . . . . . . . . . . 10
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10
7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 10 7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 10
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 10 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 10
8.1. Normative References . . . . . . . . . . . . . . . . . . 10 8.1. Normative References . . . . . . . . . . . . . . . . . . 10
8.2. Informative References . . . . . . . . . . . . . . . . . 10 8.2. Informative References . . . . . . . . . . . . . . . . . 11
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 11 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 11
1. Introduction 1. Introduction
It is useful to assign a per-node administrative tag to a router in It is useful to assign a per-node administrative tag to a router in
the OSPF domain and use it as an attribute associated with the node. the OSPF domain and use it as an attribute associated with the node.
The per-node administrative tag can be used in variety of The per-node administrative tag can be used in variety of
applications, for ex: - Traffic-engineering applications to provide applications, for ex: - Traffic-engineering applications to provide
different path-selection criteria, - Prefer or prune certain paths in different path-selection criteria, - Prefer or prune certain paths in
Loop Free Alternate (LFA) backup selection via local policies. Loop Free Alternate (LFA) backup selection via local policies.
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router in RI LSAs of different scopes. The same tag MAY be router in RI LSAs of different scopes. The same tag MAY be
advertised in multiple RI LSAs of the same scope, for example, OSPF advertised in multiple RI LSAs of the same scope, for example, OSPF
Area Border Router (ABR) may advertise the same tag in area-scope RI Area Border Router (ABR) may advertise the same tag in area-scope RI
LSAs in multiple areas connected to the ABR. LSAs in multiple areas connected to the ABR.
The per-node administrative tags are not meant to be extended by the The per-node administrative tags are not meant to be extended by the
future OSPF standards. The new OSPF extensions MUST NOT require use future OSPF standards. The new OSPF extensions MUST NOT require use
of per-node administrative tags or define well-known tag values. of per-node administrative tags or define well-known tag values.
Node administrative tags are for generic use and do not require IANA Node administrative tags are for generic use and do not require IANA
registry. The future OSPF extensions requiring well known values MAY registry. The future OSPF extensions requiring well known values MAY
define their own data signaling tailored to the needs of the feature define their own data signalling tailored to the needs of the feature
or MAY use capability TLV as defined in [RFC4970]. or MAY use capability TLV as defined in [RFC4970].
Being part of the RI LSA, the per-node administrative tag TLV must be Being part of the RI LSA, the per-node administrative tag TLV must be
reasonably small and stable. In particular, but not limited to, reasonably small and stable. In particular, but not limited to,
implementations supporting the per-node administrative tags MUST NOT implementations supporting the per-node administrative tags MUST NOT
tie advertised tags to changes in the network topology (both within tie advertised tags to changes in the network topology (both within
and outside the OSPF domain) or reachability of routes. and outside the OSPF domain) or reachability of routes.
Multiple node administrative tag TLVs MAY appear in an RI LSA or
multiple node administrative tag TLVs MAY be contained in different
instances of the RI LSA. The node administrative tags associated
with a node for the purpose of any computation or processing SHOULD
be a superset of node administrative tags from all the TLVs in all
instances of the RI LSA originated by that node.
When there is a change in the node administrative tag TLV or removal/
addition of a TLV in any instance of the RI-LSA, implementations MUST
take appropriate measures to update its state according to the
changed set of tags. Exact actions depend on features working with
administrative tags and is outside of scope of this specification.
4. Applications 4. Applications
This section lists several examples of how implementations might use This section lists several examples of how implementations might use
the Node administrative tags. These examples are given only to the Node administrative tags. These examples are given only to
demonstrate generic usefulness of the router tagging mechanism. demonstrate generic usefulness of the router tagging mechanism.
Implementation supporting this specification is not required to Implementation supporting this specification is not required to
implement any of the use cases. It is also worth noting that in some implement any of the use cases. It is also worth noting that in some
described use cases routers configured to advertise tags help other described use cases routers configured to advertise tags help other
routers in their calculations but do not themselves implement the routers in their calculations but do not themselves implement the
same functionality. same functionality.
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4.3. Controlling Remote LFA tunnel termination 4.3. Controlling Remote LFA tunnel termination
[RFC7490] proposed method of tunneling traffic after connected link [RFC7490] proposed method of tunneling traffic after connected link
failure to extend the basic LFA coverage and algorithm to find tunnel failure to extend the basic LFA coverage and algorithm to find tunnel
tail-end routers fitting LFA requirement. In most cases proposed tail-end routers fitting LFA requirement. In most cases proposed
algorithm finds more than one candidate tail-end router. In real algorithm finds more than one candidate tail-end router. In real
life network it may be desirable to exclude some nodes from the list life network it may be desirable to exclude some nodes from the list
of candidates based on the local policy. This may be either due to of candidates based on the local policy. This may be either due to
known limitations of the node (the router does not accept targeted known limitations of the node (the router does not accept targeted
LDP sessions required to implement Remote LFA tunneling) or due to LDP sessions required to implement Remote LFA tunnelling) or due to
administrative requirements (for example, it may be desirable to administrative requirements (for example, it may be desirable to
choose tail-end router among co-located devices). choose tail-end router among co-located devices).
The Node administrative tag delivers simple and scalable solution. The Node administrative tag delivers simple and scalable solution.
Remote LFA can be configured with a policy to accept during the tail- Remote LFA can be configured with a policy to accept during the tail-
end router calculation as candidates only routers advertising certain end router calculation as candidates only routers advertising certain
tag. Tagging routers allows to both exclude nodes not capable of tag. Tagging routers allows to both exclude nodes not capable of
serving as Remote LFA tunnel tail-ends and to define a region from serving as Remote LFA tunnel tail-ends and to define a region from
which tail-end router must be selected. which tail-end router must be selected.
4.4. Mobile backhaul network service deployment 4.4. Mobile backhaul network service deployment
The topology of mobile backhaul network usually adopts ring topology The topology of mobile back-haul network usually adopts ring topology
to save fiber resource and it is divided into the aggregate network to save fibre resource and it is divided into the aggregate network
and the access network. Cell Site Gateways(CSGs) connects the and the access network. Cell Site Gateways(CSGs) connects the
eNodeBs and RNC(Radio Network Controller) Site Gateways(RSGs) eNodeBs and RNC(Radio Network Controller) Site Gateways(RSGs)
connects the RNCs. The mobile traffic is transported from CSGs to connects the RNCs. The mobile traffic is transported from CSGs to
RSGs. The network takes a typical aggregate traffic model that more RSGs. The network takes a typical aggregate traffic model that more
than one access rings will attach to one pair of aggregate site than one access rings will attach to one pair of aggregate site
gateways(ASGs) and more than one aggregate rings will attach to one gateways(ASGs) and more than one aggregate rings will attach to one
pair of RSGs. pair of RSGs.
---------------- ----------------
/ \ / \
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+------+ +----+ Access +----+ / +------+ +----+ Access +----+ /
|eNodeB|---|CSG2| Ring 2 |ASG3|----------- |eNodeB|---|CSG2| Ring 2 |ASG3|-----------
+------+ +----+ +----+ +------+ +----+ +----+
\ / \ /
\ / \ /
\ / \ /
----------------- -----------------
Figure 2: Mobile Backhaul Network Figure 2: Mobile Backhaul Network
A typical mobile backhaul network with access rings and aggregate A typical mobile back-haul network with access rings and aggregate
links is shown in figure above. The mobile backhaul networks deploy links is shown in figure above. The mobile back-haul networks deploy
traffic engineering due to the strict Service Level Agreements(SLA). traffic engineering due to the strict Service Level Agreements(SLA).
The TE paths may have additional constraints to avoid passing via The TE paths may have additional constraints to avoid passing via
different access rings or to get completely disjoint backup TE paths. different access rings or to get completely disjoint backup TE paths.
The mobile backhaul networks towards the access side change The mobile back-haul networks towards the access side change
frequently due to the growing mobile traffic and addition of new frequently due to the growing mobile traffic and addition of new
eNodeBs. It's complex to satisfy the requirements using cost, link eNodeBs. It's complex to satisfy the requirements using cost, link
color or explicit path configurations. The node administrative tag color or explicit path configurations. The node administrative tag
defined in this document can be effectively used to solve the problem defined in this document can be effectively used to solve the problem
for mobile backhaul networks. The nodes in different rings can be for mobile back-haul networks. The nodes in different rings can be
assigned with specific tags. TE path computation can be enhanced to assigned with specific tags. TE path computation can be enhanced to
consider additional constraints based on node administrative tags. consider additional constraints based on node administrative tags.
4.5. Explicit routing policy 4.5. Explicit routing policy
Partially meshed network provides multiple paths between any two Partially meshed network provides multiple paths between any two
nodes in the network. In a data center environment, the topology is nodes in the network. In a data centre environment, the topology is
usually highly symmetric with many/all paths having equal cost. In a usually highly symmetric with many/all paths having equal cost. In a
long distance network, this is usually less the case for a variety of long distance network, this is usually less the case for a variety of
reasons (e.g. historic, fiber availability constraints, different reasons (e.g. historic, fibre availability constraints, different
distances between transit nodes, different roles ...). Hence between distances between transit nodes, different roles ...). Hence between
a given source and destination, a path is typically preferred over a given source and destination, a path is typically preferred over
the others, while between the same source and another destination, a the others, while between the same source and another destination, a
different path may be preferred. different path may be preferred.
+--------------------+ +--------------------+
| | | |
| +----------+ | | +----------+ |
| | | | | | | |
T-10-T | | T-10-T | |
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Thanks to Bharath R, Pushpasis Sarakar and Dhruv Dhody for useful Thanks to Bharath R, Pushpasis Sarakar and Dhruv Dhody for useful
inputs. Thanks to Chris Bowers for providing useful inputs to remove inputs. Thanks to Chris Bowers for providing useful inputs to remove
ambiguity related to tag-ordering. Thanks to Les Ginsberg and Acee ambiguity related to tag-ordering. Thanks to Les Ginsberg and Acee
Lindem for the inputs. Lindem for the inputs.
8. References 8. References
8.1. Normative References 8.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. 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, April 1998. [RFC2328] Moy, J., "OSPF Version 2", STD 54, RFC 2328,
DOI 10.17487/RFC2328, April 1998,
<http://www.rfc-editor.org/info/rfc2328>.
[RFC4970] Lindem, A., Shen, N., Vasseur, JP., Aggarwal, R., and S. [RFC4970] Lindem, A., Ed., Shen, N., Vasseur, JP., Aggarwal, R., and
Shaffer, "Extensions to OSPF for Advertising Optional S. Shaffer, "Extensions to OSPF for Advertising Optional
Router Capabilities", RFC 4970, July 2007. 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 [RFC5340] Coltun, R., Ferguson, D., Moy, J., and A. Lindem, "OSPF
for IPv6", RFC 5340, July 2008. for IPv6", RFC 5340, DOI 10.17487/RFC5340, July 2008,
<http://www.rfc-editor.org/info/rfc5340>.
[RFC7490] Bryant, S., Filsfils, C., Previdi, S., Shand, M., and N. [RFC7490] Bryant, S., Filsfils, C., Previdi, S., Shand, M., and N.
So, "Remote Loop-Free Alternate (LFA) Fast Reroute (FRR)", So, "Remote Loop-Free Alternate (LFA) Fast Reroute (FRR)",
RFC 7490, April 2015. RFC 7490, DOI 10.17487/RFC7490, April 2015,
<http://www.rfc-editor.org/info/rfc7490>.
8.2. Informative References 8.2. Informative References
[I-D.acee-ospf-rfc4970bis] [I-D.acee-ospf-rfc4970bis]
Lindem, A., Shen, N., Vasseur, J., Aggarwal, R., and S. Lindem, A., Shen, N., Vasseur, J., Aggarwal, R., and S.
Shaffer, "Extensions to OSPF for Advertising Optional Shaffer, "Extensions to OSPF for Advertising Optional
Router Capabilities", draft-acee-ospf-rfc4970bis-00 (work Router Capabilities", draft-acee-ospf-rfc4970bis-00 (work
in progress), July 2014. in progress), July 2014.
[I-D.ietf-rtgwg-lfa-manageability] [I-D.ietf-rtgwg-lfa-manageability]
Litkowski, S., Decraene, B., Filsfils, C., Raza, K., Litkowski, S., Decraene, B., Filsfils, C., Raza, K.,
Horneffer, M., and P. Sarkar, "Operational management of Horneffer, M., and P. Sarkar, "Operational management of
Loop Free Alternates", draft-ietf-rtgwg-lfa- Loop Free Alternates", draft-ietf-rtgwg-lfa-
manageability-08 (work in progress), March 2015. manageability-11 (work in progress), June 2015.
[RFC5286] Atlas, A. and A. Zinin, "Basic Specification for IP Fast [RFC5286] Atlas, A., Ed. and A. Zinin, Ed., "Basic Specification for
Reroute: Loop-Free Alternates", RFC 5286, September 2008. IP Fast Reroute: Loop-Free Alternates", RFC 5286,
DOI 10.17487/RFC5286, September 2008,
<http://www.rfc-editor.org/info/rfc5286>.
Authors' Addresses Authors' Addresses
Shraddha Hegde Shraddha Hegde
Juniper Networks, Inc. Juniper Networks, Inc.
Embassy Business Park Embassy Business Park
Bangalore, KA 560093 Bangalore, KA 560093
India India
Email: shraddha@juniper.net Email: shraddha@juniper.net
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