draft-ietf-ospf-node-admin-tag-01.txt   draft-ietf-ospf-node-admin-tag-02.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: September 10, 2015 Expires: December 3, 2015
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
March 9, 2015 June 1, 2015
Advertising per-node administrative tags in OSPF Advertising per-node administrative tags in OSPF
draft-ietf-ospf-node-admin-tag-01 draft-ietf-ospf-node-admin-tag-02
Abstract Abstract
This document describes a mechanism to advertise per-node This document describes an extension to OSPF protocol [RFC2328] to
administrative tags in This document describes an extension to OSPF add an optional operational capability, that allows tagging and
protocol [RFC2328] to add an optional operational capability, that grouping of the nodes in an OSPF domain. This allows simplification,
allows tagging and grouping of the nodes in an OSPF domain. This ease of management and control over route and path selection based on
allows simplification, ease of management and control over route and configured policies. This document describes an extension to OSPF
path selection based on configured policies. protocol [RFC2328] to advertise per-node administrative tags. This
optional operational capability allows to express and act upon
locally-defined network policy which considers node properties
conveyed by tags. Node tags may be used either by OSPF itself or by
other applications 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. node administrative-tags to the OSPFv2 and OSPFv3 protocol. It
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].
Status of this Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
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 September 10, 2015. This Internet-Draft will expire on December 3, 2015.
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.
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described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Administrative Tag TLV . . . . . . . . . . . . . . . . . . . . 4 2. Administrative Tag TLV . . . . . . . . . . . . . . . . . . . 3
3. OSPF per-node administrative tag TLV . . . . . . . . . . . . . 4 3. OSPF per-node administrative tag TLV . . . . . . . . . . . . 3
3.1. TLV format . . . . . . . . . . . . . . . . . . . . . . . . 4 3.1. TLV format . . . . . . . . . . . . . . . . . . . . . . . 3
3.2. Elements of procedure . . . . . . . . . . . . . . . . . . 5 3.2. Elements of procedure . . . . . . . . . . . . . . . . . . 4
4. Applications . . . . . . . . . . . . . . . . . . . . . . . . . 6 4. Applications . . . . . . . . . . . . . . . . . . . . . . . . 5
5. Security Considerations . . . . . . . . . . . . . . . . . . . 11 4.1. Service auto-discovery . . . . . . . . . . . . . . . . . 5
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11 4.2. Fast-Rerouting policy . . . . . . . . . . . . . . . . . . 6
7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 11 4.3. Controlling Remote LFA tunnel termination . . . . . . . . 7
8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 11 4.4. Mobile backhaul network service deployment . . . . . . . 7
8.1. Normative References . . . . . . . . . . . . . . . . . . . 11 4.5. Explicit routing policy . . . . . . . . . . . . . . . . . 8
8.2. Informative References . . . . . . . . . . . . . . . . . . 12 5. Security Considerations . . . . . . . . . . . . . . . . . . . 10
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 12 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10
7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 10
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 10
8.1. Normative References . . . . . . . . . . . . . . . . . . 10
8.2. Informative References . . . . . . . . . . . . . . . . . 10
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 traffic-engineering The per-node administrative tag can be used in variety of
applications to provide different path-selection criteria. It can applications, for ex: - Traffic-engineering applications to provide
also be used to prefer or prune certain paths in Loop Free Alternate different path-selection criteria, - Prefer or prune certain paths in
(LFA) backup selection via local policies. Loop Free Alternate (LFA) backup selection via local policies.
This document provides mechanisms to advertise per-node This document provides mechanisms to advertise per-node
administrative tags in the OSPF. Path selection is a functional set administrative tags in the OSPF. Path selection is a functional set
which applies both to TE and non-TE applications. A new TLV is which applies both to TE and non-TE applications and hence new TLV
defined for carrying per-node administrative tags and is included in for carrying per-node administrative tags is included in Router
Router Information LSA [RFC4970] . Information LSA [RFC4970] .
2. Administrative Tag TLV 2. Administrative Tag TLV
An administrative Tag is a 32-bit integer value that can be used to An administrative Tag is a 32-bit integer value that can be used to
identify a group of nodes in the OSPF domain. identify a group of nodes in the OSPF domain.
The new TLV defined will be carried within an RI LSA for OSPFV2 and The new TLV defined will be carried within an RI LSA for OSPFV2 and
OSPFV3. Router information LSA [RFC4970] can have link, area or AS OSPFV3. Router information LSA [RFC4970] can have link, area or AS
level flooding scope. Choosing the flooding scope to flood the group level flooding scope. Choosing the flooding scope to flood the group
tags are defined by the policies and is a local matter. tags are defined by the policies and is a local matter.
skipping to change at page 4, line 41 skipping to change at page 3, line 41
node advertises the set of groups it is part of in the OSPF domain. node advertises the set of groups it is part of in the OSPF domain.
(for example, all PE-nodes are configured with certain tag value, all (for example, all PE-nodes are configured with certain tag value, all
P-nodes are configured with a different tag value in a domain). P-nodes are configured with a different tag value in a domain).
Multiple TLVs MAY be added in same RI-LSA or in different instance of Multiple TLVs MAY be added in same RI-LSA or in different instance of
the RI LSA as defined in [I-D.acee-ospf-rfc4970bis]. the RI LSA as defined in [I-D.acee-ospf-rfc4970bis].
3. OSPF per-node administrative tag TLV 3. OSPF per-node administrative tag TLV
3.1. TLV format 3.1. TLV format
As per [RFC4970], the format of the TLVs within the body of an RI LSA [RFC4970], defines Router Information (RI) LSA which may be used to
is the same as the format used by the Traffic Engineering Extensions advertise properties of the originating router. Payload of the RI
to OSPF [RFC3630]. LSA consists of one or more nested Type/Length/Value (TLV) triplets.
Node administrative tags are advertised in the Node Administrative
The LSA payload consists of one or more nested Type/Length/Value Tag TLV. The format of Node Administrative Tag TLV is:
(TLV) triplets. The format of each TLV is:
0 1 2 3 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 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 | | Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Administrative Tag #1 | | Administrative Tag #1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Administrative Tag #2 | | Administrative Tag #2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// // // //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Administrative Tag #N | | Administrative Tag #N |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: OSPF per-node Administrative Tag TLV Figure 1: OSPF per-node Administrative Tag TLV
Type : TBA Type : TBA, Suggested value 10
Length: A 16-bit field that indicates the length of the value portion Length: A 16-bit field that indicates the length of the value portion
in octets and will be a multiple of 4 octets dependent on the number in octets and will be a multiple of 4 octets dependent on the number
of tags advertised. of tags advertised.
Value: A sequence of multiple 4 octets defining the administrative Value: A sequence of multiple 4 octets defining the administrative
tags. Atleast one tag MUST be carried if this TLV is included in the tags. At least one tag MUST be carried if this TLV is included in
RI-LSA. the RI-LSA.
3.2. Elements of procedure 3.2. Elements of procedure
Meaning of the Node administrative tags is generally opaque to OSPF. Meaning of the Node administrative tags is generally opaque to OSPF.
Router advertising the per-node administrative tag (or tags) may be Router advertising the per-node administrative tag (or tags) may be
configured to do so without knowing (or even explicitly supporting) configured to do so without knowing (or even explicitly supporting)
functionality implied by the tag. functionality implied by the tag.
Interpretation of tag values is specific to the administrative domain Interpretation of tag values is specific to the administrative domain
of a particular network operator. The meaning of a per-node of a particular network operator. The meaning of a per-node
skipping to change at page 6, line 45 skipping to change at page 5, line 44
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.
1. Service auto-discovery 4.1. Service auto-discovery
Router tagging may be used to automatically discover group of Router tagging may be used to automatically discover group of routers
routers sharing a particular service. sharing a particular service.
For example, service provider might desire to establish full mesh For example, service provider might desire to establish full mesh of
of MPLS TE tunnels between all PE routers in the area of MPLS VPN MPLS TE tunnels between all PE routers in the area of MPLS VPN
network. Marking all PE routers with a tag and configuring network. Marking all PE routers with a tag and configuring devices
devices with a policy to create MPLS TE tunnels to all other with a policy to create MPLS TE tunnels to all other devices
devices advertising this tag will automate maintenance of the advertising this tag will automate maintenance of the full mesh.
full mesh. When new PE router is added to the area, all other PE When new PE router is added to the area, all other PE devices will
devices will open TE tunnels to it without the need of open TE tunnels to it without the need of reconfiguring them.
reconfiguring them.
2. Fast-Rerouting policy 4.2. Fast-Rerouting policy
Increased deployment of Loop Free Alternates (LFA) as defined in Increased deployment of Loop Free Alternates (LFA) as defined in
[RFC5286] poses operation and management challenges. [RFC5286] poses operation and management challenges.
[I-D.ietf-rtgwg-lfa-manageability] proposes policies which, when [I-D.ietf-rtgwg-lfa-manageability] proposes policies which, when
implemented, will ease LFA operation concerns. implemented, will ease LFA operation concerns.
One of the proposed refinements is to be able to group the nodes One of the proposed refinements is to be able to group the nodes in
in IGP domain with administrative tags and engineer the LFA based IGP domain with administrative tags and engineer the LFA based on
on configured policies. configured policies.
(a) Administrative limitation of LFA scope (a) Administrative limitation of LFA scope
Service provider access infrastructure is frequently Service provider access infrastructure is frequently designed in
designed in layered approach with each layer of devices layered approach with each layer of devices serving different
serving different purposes and thus having different purposes and thus having different hardware capabilities and
hardware capabilities and configured software features. configured software features. When LFA repair paths are being
When LFA repair paths are being computed, it may be computed, it may be desirable to exclude devices from being
desirable to exclude devices from being considered as LFA considered as LFA candidates based on their layer.
candidates based on their layer.
For example, if the access infrastructure is divided into For example, if the access infrastructure is divided into the
the Access, Distribution and Core layers it may be desirable Access, Distribution and Core layers it may be desirable for a
for a Distribution device to compute LFA only via Distribution device to compute LFA only via Distribution or Core
Distribution or Core devices but not via Access devices. devices but not via Access devices. This may be due to features
This may be due to features enabled on Access routers; due enabled on Access routers; due to capacity limitations or due to
to capacity limitations or due to the security requirements. the security requirements. Managing such a policy via
Managing such a policy via configuration of the router configuration of the router computing LFA is cumbersome and error
computing LFA is cumbersome and error prone. prone.
With the Node administrative tags it is possible to assign a With the Node administrative tags it is possible to assign a tag
tag to each layer and implement LFA policy of computing LFA to each layer and implement LFA policy of computing LFA repair
repair paths only via neighbors which advertise the Core or paths only via neighbors which advertise the Core or Distribution
Distribution tag. This requires minimal per-node tag. This requires minimal per-node configuration and network
configuration and network automatically adapts when new automatically adapts when new links or routers are added.
links or routers are added.
(b) LFA calculation optimization (b) LFA calculation optimization
Calculation of LFA paths may require significant resources Calculation of LFA paths may require significant resources of the
of the router. One execution of Dijkstra algorithm is router. One execution of Dijkstra algorithm is required for each
required for each neighbor eligible to become next hop of neighbor eligible to become next hop of repair paths. Thus a
repair paths. Thus a router with a few hundreds of router with a few hundreds of neighbors may need to execute the
neighbors may need to execute the algorithm hundreds of algorithm hundreds of times before the best (or even valid)
times before the best (or even valid) repair path is found. repair path is found. Manually excluding from the calculation
Manually excluding from the calculation neighbors which are neighbors which are known to provide no valid LFA (such as
known to provide no valid LFA (such as single-connected single-connected routers) may significantly reduce number of
routers) may significantly reduce number of Dijkstra Dijkstra algorithm runs.
algorithm runs.
LFA calculation policy may be configured so that routers LFA calculation policy may be configured so that routers
advertising certain tag value are excluded from LFA advertising certain tag value are excluded from LFA calculation
calculation even if they are otherwise suitable. even if they are otherwise suitable.
3. Controlling Remote LFA tunnel termination 4.3. Controlling Remote LFA tunnel termination
[I-D.ietf-rtgwg-remote-lfa] proposed method of tunneling traffic [RFC7490] proposed method of tunneling traffic after connected link
after connected link failure to extend the basic LFA coverage and failure to extend the basic LFA coverage and algorithm to find tunnel
algorithm to find tunnel tail-end routers fitting LFA tail-end routers fitting LFA requirement. In most cases proposed
requirement. In most cases proposed algorithm finds more than algorithm finds more than one candidate tail-end router. In real
one candidate tail-end router. In real life network it may be life network it may be desirable to exclude some nodes from the list
desirable to exclude some nodes from the list of candidates based of candidates based on the local policy. This may be either due to
on the local policy. This may be either due to known limitations known limitations of the node (the router does not accept targeted
of the node (the router does not accept targeted LDP sessions LDP sessions required to implement Remote LFA tunneling) or due to
required to implement Remote LFA tunneling) 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 The Node administrative tag delivers simple and scalable solution.
solution. Remote LFA can be configured with a policy to accept Remote LFA can be configured with a policy to accept during the tail-
during the tail-end router calculation as candidates only routers end router calculation as candidates only routers advertising certain
advertising certain tag. Tagging routers allows to both exclude tag. Tagging routers allows to both exclude nodes not capable of
nodes not capable of serving as Remote LFA tunnel tail-ends and serving as Remote LFA tunnel tail-ends and to define a region from
to define a region from which tail-end router must be selected. which tail-end router must be selected.
4. Mobile backhaul network service deployment 4.4. Mobile backhaul network service deployment
The topology of mobile backhaul network usually adopts ring The topology of mobile backhaul network usually adopts ring topology
topology to save fiber resource and it is divided into the to save fiber resource and it is divided into the aggregate network
aggregate network and the access network. Cell Site and the access network. Cell Site Gateways(CSGs) connects the
Gateways(CSGs) connects the eNodeBs and RNC(Radio Network eNodeBs and RNC(Radio Network Controller) Site Gateways(RSGs)
Controller) Site Gateways(RSGs) connects the RNCs. The mobile connects the RNCs. The mobile traffic is transported from CSGs to
traffic is transported from CSGs to RSGs. The network takes a RSGs. The network takes a typical aggregate traffic model that more
typical aggregate traffic model that more than one access rings than one access rings will attach to one pair of aggregate site
will attach to one pair of aggregate site gateways(ASGs) and more gateways(ASGs) and more than one aggregate rings will attach to one
than one aggregate rings will attach to one pair of RSGs. pair of RSGs.
---------------- ----------------
/ \ / \
/ \ / \
/ \ / \
+------+ +----+ Access +----+ +------+ +----+ Access +----+
|eNodeB|---|CSG1| Ring 1 |ASG1|------------- |eNodeB|---|CSG1| Ring 1 |ASG1|------------
+------+ +----+ +----+ \ +------+ +----+ +----+ \
\ / \ \ / \
\ / +----+ +---+ \ / +----+ +---+
\ +----+ |RSG1|----|RNC| \ +----+ |RSG1|----|RNC|
-------------| | Aggregate +----+ +---+ -------------| | Aggregate +----+ +---+
|ASG2| Ring | |ASG2| Ring |
-------------| | +----+ +---+ -------------| | +----+ +---+
/ +----+ |RSG2|----|RNC| / +----+ |RSG2|----|RNC|
/ \ +----+ +---+ / \ +----+ +---+
/ \ / / \ /
+------+ +----+ 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 backhaul network with access rings and aggregate
links is shown in figure above. The mobile backhaul networks links is shown in figure above. The mobile backhaul networks deploy
deploy traffic engineering due to the strict Service Level traffic engineering due to the strict Service Level Agreements(SLA).
Agreements(SLA). The TE paths may have additional constraints to The TE paths may have additional constraints to avoid passing via
avoid passing via different access rings or to get completely different access rings or to get completely disjoint backup TE paths.
disjoint backup TE paths. The mobile backhaul networks towards The mobile backhaul networks towards the access side change
the access side change frequently due to the growing mobile frequently due to the growing mobile traffic and addition of new
traffic and addition of new eNodeBs. It's complex to satisfy the eNodeBs. It's complex to satisfy the requirements using cost, link
requirements using cost, link color or explicit path color or explicit path configurations. The node administrative tag
configurations. The node administrative tag defined in this defined in this document can be effectively used to solve the problem
document can be effectively used to solve the problem for mobile for mobile backhaul networks. The nodes in different rings can be
backhaul networks. The nodes in different rings can be assigned assigned with specific tags. TE path computation can be enhanced to
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.
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 nodes in the network. In a data center environment, the topology is
is usually highly symmetric with many/all paths having equal usually highly symmetric with many/all paths having equal cost. In a
cost. In a long distance network, this is usually less the case long distance network, this is usually less the case for a variety of
for a variety of reasons (e.g. historic, fiber availability reasons (e.g. historic, fiber availability constraints, different
constraints, different distances between transit nodes, different distances between transit nodes, different roles ...). Hence between
roles ...). Hence between a given source and destination, a path a given source and destination, a path is typically preferred over
is typically preferred over the others, while between the same the others, while between the same source and another destination, a
source and another destination, a different path may be different path may be preferred.
preferred.
+--------------------+ +--------------------+
| | | |
| +----------+ | | +----------+ |
| | | | | | | |
T-10-T | | T-10-T | |
/| /| | | /| /| | |
/ | / | | | / | / | | |
--+ | | | | | --+ | | | | |
/ +--+-+ 100 | | / +--+-+ 100 | |
/ / | | | | / / | | | |
/ / R-18-R | | / / R-18-R | |
/ / /\ /\ | | / / /\ /\ | |
/ | / \ / \ | | / | / \ / \ | |
/ | / x \ | | / | / x \ | |
A-25-A 10 10 \ \ | | A-25-A 10 10 \ \ | |
/ / 10 10 | | / / 10 10 | |
/ / \ \ | | / / \ \ | |
A-25-A A-25-A | | A-25-A A-25-A | |
\ \ / / | | \ \ / / | |
201 201 201 201 | | 201 201 201 201 | |
\ \ / / | | \ \ / / | |
\ x / | | \ x / | |
\ / \ / | | \ / \ / | |
\/ \/ | | \/ \/ | |
I-24-I 100 100 I-24-I 100 100
| | | | | | | |
| +-----------+ | | +-----------+ |
| | | |
+---------------------+ +---------------------+
Figure 3: Explicit Routing topology Figure 3: Explicit Routing topology
In the above topology, operator may want to enforce the following In the above topology, operator may want to enforce the following
high level explicitly routed policies: - Traffic from A nodes to high level explicitly routed policies:
A nodes must not go through I nodes - Traffic from A nodes to I
nodes must not go through R and T nodes With node admin tag, tag - Traffic from A nodes to A nodes must not go through I nodes
A can be configured on all A nodes, (similarly I, R, T), and then
configure this single CSPF policy on all A nodes to avoid I nodes - Traffic from A nodes to I nodes must not go through R and T
for path calculation. nodes
With node admin tags, tag A (resp. I, R, T) can be configured on all
A (resp. I, R, T) nodes to advertise their role. Then a generic
CSPF policy can be configured on all A nodes to enforce the above
explicit routing objectives. (e.g. CSPF to destinations A exclude
node with tags I).
5. Security Considerations 5. Security Considerations
This document does not introduce any further security issues other This document does not introduce any further security issues other
than those discussed in [RFC2328] and [RFC5340]. than those discussed in [RFC2328] and [RFC5340].
6. IANA Considerations 6. IANA Considerations
This specification updates one OSPF registry: OSPF Router Information This specification updates one OSPF registry: OSPF Router Information
(RI) TLVs Registry (RI) TLVs Registry
skipping to change at page 11, line 41 skipping to change at page 10, line 36
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, March 1997.
[RFC2328] Moy, J., "OSPF Version 2", STD 54, RFC 2328, April 1998. [RFC2328] Moy, J., "OSPF Version 2", STD 54, RFC 2328, April 1998.
[RFC3630] Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering
(TE) Extensions to OSPF Version 2", RFC 3630,
September 2003.
[RFC4970] Lindem, A., Shen, N., Vasseur, JP., Aggarwal, R., and S. [RFC4970] Lindem, A., Shen, N., Vasseur, JP., Aggarwal, R., and S.
Shaffer, "Extensions to OSPF for Advertising Optional Shaffer, "Extensions to OSPF for Advertising Optional
Router Capabilities", RFC 4970, July 2007. Router Capabilities", RFC 4970, July 2007.
[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, July 2008.
[RFC7490] Bryant, S., Filsfils, C., Previdi, S., Shand, M., and N.
So, "Remote Loop-Free Alternate (LFA) Fast Reroute (FRR)",
RFC 7490, April 2015.
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. psarkar@juniper.net, "Operational Horneffer, M., and P. Sarkar, "Operational management of
management of Loop Free Alternates", Loop Free Alternates", draft-ietf-rtgwg-lfa-
draft-ietf-rtgwg-lfa-manageability-04 (work in progress), manageability-08 (work in progress), March 2015.
August 2014.
[I-D.ietf-rtgwg-remote-lfa]
Bryant, S., Filsfils, C., Previdi, S., Shand, M., and S.
Ning, "Remote LFA FRR", draft-ietf-rtgwg-remote-lfa-02
(work in progress), May 2013.
[RFC5286] Atlas, A. and A. Zinin, "Basic Specification for IP Fast [RFC5286] Atlas, A. and A. Zinin, "Basic Specification for IP Fast
Reroute: Loop-Free Alternates", RFC 5286, September 2008. Reroute: Loop-Free Alternates", RFC 5286, September 2008.
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
skipping to change at page 13, line 16 skipping to change at page 12, line 4
1194 N. Mathilda Ave. 1194 N. Mathilda Ave.
Sunnyvale, CA 94089 Sunnyvale, CA 94089
US US
Email: hannes@juniper.net Email: hannes@juniper.net
Rob Shakir Rob Shakir
British Telecom British Telecom
Email: rob.shakir@bt.com Email: rob.shakir@bt.com
Anton Smirnov Anton Smirnov
Cisco Systems, Inc. Cisco Systems, Inc.
De Kleetlaan 6a De Kleetlaan 6a
Diegem, 1831 Diegem 1831
Belgium Belgium
Email: as@cisco.com Email: as@cisco.com
Li zhenbin Li zhenbin
Huawei Technologies Huawei Technologies
Huawei Bld. No.156 Beiqing Rd Huawei Bld. No.156 Beiqing Rd
Beijing, 100095 Beijing 100095
China China
Email: lizhenbin@huawei.com Email: lizhenbin@huawei.com
Bruno Decraene Bruno Decraene
Orange Orange
Email: bruno.decraene@orange.com Email: bruno.decraene@orange.com
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