GENWiki

Premier IT Outsourcing and Support Services within the UK

User Tools

Site Tools


rfc:rfc6827

Internet Engineering Task Force (IETF) A. Malis, Ed. Request for Comments: 6827 Verizon Communications Obsoletes: 5787 A. Lindem, Ed. Updates: 5786 Ericsson Category: Standards Track D. Papadimitriou, Ed. ISSN: 2070-1721 Alcatel-Lucent

                                                          January 2013
           Automatically Switched Optical Network (ASON)
                    Routing for OSPFv2 Protocols

Abstract

 The ITU-T has defined an architecture and requirements for operating
 an Automatically Switched Optical Network (ASON).
 The Generalized Multiprotocol Label Switching (GMPLS) protocol suite
 is designed to provide a control plane for a range of network
 technologies.  These include optical networks such as time division
 multiplexing (TDM) networks including the Synchronous Optical
 Network/Synchronous Digital Hierarchy (SONET/SDH), Optical Transport
 Networks (OTNs), and lambda switching optical networks.
 The requirements for GMPLS routing to satisfy the requirements of
 ASON routing and an evaluation of existing GMPLS routing protocols
 are provided in other documents.  This document defines extensions to
 the OSPFv2 Link State Routing Protocol to meet the requirements for
 routing in an ASON.
 Note that this work is scoped to the requirements and evaluation
 expressed in RFC 4258 and RFC 4652 and the ITU-T Recommendations that
 were current when those documents were written.  Future extensions or
 revisions of this work may be necessary if the ITU-T Recommendations
 are revised or if new requirements are introduced into a revision of
 RFC 4258.  This document obsoletes RFC 5787 and updates RFC 5786.

Malis, et al. Standards Track [Page 1] RFC 6827 ASON Routing for OSPFv2 Protocols January 2013

Status of This Memo

 This is an Internet Standards Track document.
 This document is a product of the Internet Engineering Task Force
 (IETF).  It represents the consensus of the IETF community.  It has
 received public review and has been approved for publication by the
 Internet Engineering Steering Group (IESG).  Further information on
 Internet Standards is available in Section 2 of RFC 5741.
 Information about the current status of this document, any errata,
 and how to provide feedback on it may be obtained at
 http://www.rfc-editor.org/info/rfc6827.

Copyright Notice

 Copyright (c) 2013 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
 Provisions Relating to IETF Documents
 (http://trustee.ietf.org/license-info) in effect on the date of
 publication of this document.  Please review these documents
 carefully, as they describe your rights and restrictions with respect
 to this document.  Code Components extracted from this document must
 include Simplified BSD License text as described in Section 4.e of
 the Trust Legal Provisions and are provided without warranty as
 described in the Simplified BSD License.

Malis, et al. Standards Track [Page 2] RFC 6827 ASON Routing for OSPFv2 Protocols January 2013

Table of Contents

 1. Introduction ....................................................4
    1.1. Conventions Used in This Document ..........................5
 2. Routing Areas, OSPF Areas, and Protocol Instances ...............5
 3. Terminology and Identification ..................................6
 4. Reachability ....................................................7
 5. Link Attribute ..................................................8
    5.1. Local Adaptation ...........................................8
    5.2. Bandwidth Accounting .......................................9
 6. Routing Information Scope .......................................9
    6.1. Link Advertisement (Local and Remote TE Router ID Sub-TLV) .9
    6.2. Reachability Advertisement (Local TE Router ID Sub-TLV) ...11
 7. Routing Information Dissemination ..............................11
    7.1. Import/Export Rules .......................................12
    7.2. Loop Prevention ...........................................12
         7.2.1. Inter-RA Export Upward/Downward Sub-TLVs ...........13
         7.2.2. Inter-RA Export Upward/Downward Sub-TLV Processing .13
 8. OSPFv2 Scalability .............................................14
 9. Security Considerations ........................................15
 10. IANA Considerations ...........................................15
    10.1. Sub-TLVs of the Link TLV .................................15
    10.2. Sub-TLVs of the Node Attribute TLV .......................16
    10.3. Sub-TLVs of the Router Address TLV .......................16
 11. Management Considerations .....................................17
    11.1. Routing Area (RA) Isolation ..............................17
    11.2. Routing Area (RA) Topology/Configuration Changes .........17
 12. Comparison to Requirements in RFC 4258 ........................17
 13. References ....................................................25
    13.1. Normative References .....................................25
    13.2. Informative References ...................................25
 14. Acknowledgements ..............................................26
    14.1. RFC 5787 Acknowledgements ................................26
 Appendix A. ASON Terminology ......................................27
 Appendix B. ASON Routing Terminology ..............................28
 Appendix C. Changes from RFC 5787 .................................29

Malis, et al. Standards Track [Page 3] RFC 6827 ASON Routing for OSPFv2 Protocols January 2013

1. Introduction

 The Generalized Multiprotocol Label Switching (GMPLS) [RFC3945]
 protocol suite is designed to provide a control plane for a range of
 network technologies.  These include optical networks such as time
 division multiplexing (TDM) networks including SONET/SDH, Optical
 Transport Networks (OTNs), and lambda switching optical networks.
 The ITU-T defines the architecture of the Automatically Switched
 Optical Network (ASON) in [G.8080].
 [RFC4258] describes the routing requirements for the GMPLS suite of
 routing protocols to support the capabilities and functionality of
 ASON control planes identified in [G.7715] and in [G.7715.1].
 [RFC4652] evaluates the IETF Link State routing protocols against the
 requirements identified in [RFC4258].  Section 7.1 of [RFC4652]
 summarizes the capabilities to be provided by OSPFv2 [RFC2328] in
 support of ASON routing.  This document describes the OSPFv2
 specifics for ASON routing.
 Multi-layer transport networks are constructed from multiple networks
 of different technologies operating in a client-server relationship.
 The ASON routing model includes the definition of routing levels that
 provide scaling and confidentiality benefits.  In multi-level
 routing, domains called routing areas (RAs) are arranged in a
 hierarchical relationship.  Note that as described in [RFC4652],
 there is no implied relationship between multi-layer transport
 networks and multi-level routing.  The multi-level routing mechanisms
 described in this document work for both single-layer and multi-layer
 networks.
 Implementations may support a hierarchical routing topology (multi-
 level) for multiple transport network layers and/or a hierarchical
 routing topology for a single transport network layer.
 This document describes the processing of the generic (technology-
 independent) link attributes that are defined in [RFC3630],
 [RFC4202], and [RFC4203] and that are extended in this document.  As
 described in Section 5.2, technology-specific traffic engineering
 attributes and their processing may be defined in other documents
 that complement this document.

Malis, et al. Standards Track [Page 4] RFC 6827 ASON Routing for OSPFv2 Protocols January 2013

 Note that this work is scoped to the requirements and evaluation
 expressed in [RFC4258] and [RFC4652] and the ITU-T Recommendations
 that were current when those documents were written.  Future
 extensions or revisions of this work may be necessary if the ITU-T
 Recommendations are revised or if new requirements are introduced
 into a revision of [RFC4258].

1.1. Conventions Used in This Document

 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].
 The reader is assumed to be familiar with the terminology and
 requirements developed in [RFC4258] and the evaluation outcomes
 described in [RFC4652].
 General ASON terminology is provided in Appendix A.  ASON routing
 terminology is described in Appendix B.

2. Routing Areas, OSPF Areas, and Protocol Instances

 An ASON routing area (RA) represents a partition of the transport
 plane, and its identifier is used within the control plane as the
 representation of this partition.
 RAs are hierarchically contained: a higher-level (parent) RA contains
 lower-level (child) RAs that in turn MAY also contain RAs.  Thus, RAs
 contain RAs that recursively define successive hierarchical RA
 levels.  Routing information may be exchanged between levels of the
 RA hierarchy, i.e., Level N+1 and N, where Level N represents the RAs
 contained by Level N+1.  The links connecting RAs may be viewed as
 external links (inter-RA links), and the links representing
 connectivity within an RA may be viewed as internal links (intra-RA
 links).  The external links to an RA at one level of the hierarchy
 may be internal links in the parent RA.  Intra-RA links of a child RA
 MAY be hidden from the parent RA's view [RFC4258].
 An ASON RA can be mapped to an OSPF area, but the hierarchy of ASON
 RA levels does not map to the hierarchy of OSPF areas.  Instead,
 successive hierarchical levels of RAs MUST be represented by separate
 instances of the protocol.  Thus, inter-level routing information
 exchange (as described in Section 7) involves the export and import
 of routing information between protocol instances.

Malis, et al. Standards Track [Page 5] RFC 6827 ASON Routing for OSPFv2 Protocols January 2013

 An ASON RA may therefore be identified by the combination of its OSPF
 Instance ID and its OSPF Area ID.  With proper and careful network-
 wide configuration, this can be achieved using just the OSPF Area ID,
 and this process is RECOMMENDED in this document.  These concepts are
 discussed in Section 7.
 A key ASON requirement is the support of multiple transport planes or
 layers.  Each transport node has associated topology (links and
 reachability), which is used for ASON routing.

3. Terminology and Identification

 This section describes the mapping of key ASON entities to OSPF
 entities.  Appendix A contains a complete glossary of ASON routing
 terminology.
 There are three categories of identifiers used for ASON routing
 (G.7715.1): transport-plane names, control-plane identifiers for
 components, and Signaling Communications Network (SCN) addresses.
 This section discusses the mapping between ASON routing identifiers
 and corresponding identifiers defined for GMPLS routing and how these
 support the physical (or logical) separation of transport-plane
 entities and control-plane components.  GMPLS supports this
 separation of identifiers and planes.
 In the context of OSPF Traffic Engineering (TE), an ASON transport
 node corresponds to a unique OSPF TE node.  An OSPF TE node is
 uniquely identified by the TE Router Address TLV [RFC3630].  In this
 document, the TE Router Address is referred to as the TE Router ID.
 In GMPLS, TE router addresses are advertised as reachable in both the
 control and transport planes, see Section 4 below.  Furthermore, the
 TE Router ID should not be confused with the OSPF Router ID that
 uniquely identifies an OSPF router within an OSPF routing domain
 [RFC2328] and is in a name space for control-plane components.
 The Router Address top-level TLV definition, processing, and usage
 are largely unchanged from [RFC3630].  This TLV specifies a stable
 OSPF TE node IP address, i.e., the IP address is always reachable
 when there is IP connectivity to the associated OSPF TE node.
 ASON defines a Routing Controller (RC) as an entity that handles
 (abstract) information needed for routing and the routing information
 exchange with peering RCs by operating on the Routing Database (RDB).
 ASON defines a Protocol Controller (PC) as an entity that handles
 protocol-specific message exchanges according to the reference point
 over which the information is exchanged (e.g., E-NNI, I-NNI) and
 internal exchanges with the RC [RFC4258].  In this document, an OSPF
 router advertising ASON TE topology information will perform both the

Malis, et al. Standards Track [Page 6] RFC 6827 ASON Routing for OSPFv2 Protocols January 2013

 functions of the RC and PC.  The OSPF routing domain comprises the
 control plane, and each OSPF router is uniquely identified by its
 OSPF Router ID [RFC2328].

4. Reachability

 In ASON, reachability information describes the set of endpoints that
 are reachable by the associated node in the transport plane.
 Reachability information represents transport-plane resources, e.g.,
 an optical cross-connect interface, and uses transport-plane
 identifiers.
 In order to advertise blocks of reachable address prefixes, a
 summarization mechanism is introduced that is based on the techniques
 described in [RFC5786].  For ASON reachability advertisement, blocks
 of reachable address prefixes are advertised together with the
 associated transport-plane node.  The transport-plane node is
 identified in OSPF TE Link State Advertisements (LSAs) by its TE
 Router ID, as discussed in Section 6.
 In order to support ASON reachability advertisement, the Node
 Attribute TLV defined in [RFC5786] is used to advertise the
 combination of a TE Router ID and its set of associated reachable
 address prefixes.  The Node Attribute TLV can contain the following
 sub-TLVs:
  1. Local TE Router ID sub-TLV: Length: 4; Defined in Section 6.2
  2. Node IPv4 Local Address sub-TLV: Length: variable; [RFC5786]
  3. Node IPv6 Local Address sub-TLV: Length: variable; [RFC5786]
 A router may support multiple transport nodes as discussed in
 Section 6 and, as a result, may be required to advertise reachability
 separately for each transport node.  As a consequence, it MUST be
 possible for the router to originate more than one TE LSA containing
 the Node Attribute TLV when used for ASON reachability advertisement.
 Hence, the Node Attribute TLV [RFC5786] advertisement rules are
 relaxed.  A Node Attribute TLV MAY appear in more than one TE LSA
 originated by the RC when the RC is advertising reachability
 information for a different transport node identified by the Local TE
 Router sub-TLV (refer to Section 6.2).
 As specified in [RFC3630], TE-advertised router addresses are also
 advertised as reachable in the control plane and are therefore also
 valid identifiers in the ASON SCN name space.

Malis, et al. Standards Track [Page 7] RFC 6827 ASON Routing for OSPFv2 Protocols January 2013

5. Link Attribute

 With the exception of local adaptation (described below), the mapping
 of link attributes and characteristics to OSPF TE Link TLV sub-TLVs
 is unchanged [RFC4652].  OSPF TE Link TLV sub-TLVs are described in
 [RFC3630] and [RFC4203].  Advertisement of this information SHOULD be
 supported on a per-layer basis, i.e., one TE LSA per unique switching
 capability and bandwidth granularity combination.

5.1. Local Adaptation

 Local adaptation is defined as a TE link attribute (i.e., sub-TLV)
 that describes the cross/inter-layer relationships.
 The Interface Switching Capability Descriptor (ISCD) TE Attribute
 [RFC4202] identifies the ability of the TE link to support cross-
 connection to another link within the same layer.  When advertising
 link adaptation, it also identifies the ability to use a locally
 terminated connection that belongs to one layer as a data link for
 another layer (adaptation capability).  However, the information
 associated with the ability to terminate connections within that
 layer (referred to as the termination capability) is advertised with
 the adaptation capability.
 For instance, a link between two optical cross-connects will contain
 at least one ISCD attribute describing the Lambda Switching Capable
 (LSC) switching capability.  Conversely, a link between an optical
 cross-connect and an IP/MPLS Label Switching Router (LSR) will
 contain at least two ISCD attributes, one for the description of the
 LSC termination capability and one for the Packet Switching Capable
 (PSC) adaptation capability.
 In OSPFv2, the Interface Switching Capability Descriptor (ISCD) is a
 sub-TLV (type 15) of the top-level Link TLV (type 2) [RFC4203].  The
 adaptation and termination capabilities are advertised using two
 separate ISCD sub-TLVs within the same top-level Link TLV.
 An interface MAY have more than one ISCD sub-TLV, per [RFC4202] and
 [RFC4203].  Hence, the corresponding advertisements should not result
 in any compatibility issues.

Malis, et al. Standards Track [Page 8] RFC 6827 ASON Routing for OSPFv2 Protocols January 2013

5.2. Bandwidth Accounting

 GMPLS routing defines an ISCD that provides, among other things, the
 quantities of the maximum/minimum available bandwidth per priority
 for Label Switched Paths (LSPs).  One or more ISCD sub-TLVs can be
 associated with an interface, per [RFC4202] and [RFC4203].  This
 information, combined with the Unreserved Bandwidth Link TLV sub-TLV
 [RFC3630], provides the basis for bandwidth accounting.
 In the ASON context, additional information may be included when the
 representation and information in the other advertised fields are not
 sufficient for a specific technology, e.g., SDH.  The definition of
 technology-specific information elements is beyond the scope of this
 document.  Some technologies will not require additional information
 beyond what is already defined in [RFC3630], [RFC4202], and
 [RFC4203].

6. Routing Information Scope

 For ASON routing, the control-plane component routing adjacency
 topology (i.e., the associated Protocol Controller (PC) connectivity)
 and the transport topology are not assumed to be congruent [RFC4258].
 Hence, a single OSPF router (i.e., the PC) MUST be able to advertise
 on behalf of multiple transport-layer nodes.  The OSPF routers are
 identified by OSPF Router ID, and the transport nodes are identified
 by TE Router ID.
 The Router Address TLV [RFC3630] is used to advertise the TE Router
 ID associated with the advertising Routing Controller (RC).  TE
 Router IDs for additional transport nodes are advertised through
 specification of the Local TE Router Identifier in the Local and
 Remote TE Router TE sub-TLV and the Local TE Router Identifier
 sub-TLV described in the sections below.  These Local TE Router
 Identifiers are typically used as the local endpoints for TE LSPs
 terminating on the associated transport node.
 The use of multiple OSPF Routers to advertise TE information for the
 same transport node is not considered a required use case and is not
 discussed further in this document.

6.1. Link Advertisement (Local and Remote TE Router ID Sub-TLV)

 When an OSPF Router advertises on behalf of multiple transport nodes,
 the link endpoints cannot be automatically assigned to a single
 transport node associated with the advertising router.  In this case,
 the local and remote transport nodes MUST be identified by TE Router
 ID to unambiguously specify the transport topology.

Malis, et al. Standards Track [Page 9] RFC 6827 ASON Routing for OSPFv2 Protocols January 2013

 For this purpose, a new sub-TLV of the OSPFv2 TE LSA top-level Link
 TLV is introduced that defines the Local and Remote TE Router ID.
 The Type field of the Local and Remote TE Router ID sub-TLV is
 assigned the value 10 (see Section 10).  The Length field takes the
 value 8.  The Value field of this sub-TLV contains 4 octets of the
 Local TE Router Identifier followed by 4 octets of the Remote TE
 Router Identifier.  The value of the Local and Remote TE Router
 Identifier MUST NOT be set to 0.
 The format of the Local and Remote TE Router ID sub-TLV is:
  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 (10)           |          Length (8)           |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                 Local TE Router Identifier                    |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                 Remote TE Router Identifier                   |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 This sub-TLV MUST be included as a sub-TLV of the top-level Link TLV
 if the OSPF router is advertising on behalf of one or more transport
 nodes having TE Router IDs different from the TE Router ID advertised
 in the Router Address TLV.  For consistency, this sub-TLV MUST be
 included when OSPF is used for the advertisement of ASON information
 as described herein.  If it is not included in a Link TLV, or if a
 value of 0 is specified for the Local or Remote TE Router Identifier,
 the Link TLV will not be used for transport-plane path computation.
 Additionally, the condition SHOULD be logged for possible action by
 the network operator.
 Note: The Link ID sub-TLV identifies the other end of the link (i.e.,
 Router ID of the neighbor for point-to-point links) [RFC3630].  When
 the Local and Remote TE Router ID sub-TLV is present, it MUST be used
 to identify local and remote transport node endpoints for the link
 and the Link-ID sub-TLV MUST be ignored.  In fact, when the Local and
 Remote TE Router ID sub-TLV is specified, the Link-ID sub-TLV MAY be
 omitted.  The Local and Remote TE Router ID sub-TLV, if specified,
 MUST only be specified once.  If specified more than once, instances
 other than the first will be ignored and the condition SHOULD be
 logged for possible action by the network operator.

Malis, et al. Standards Track [Page 10] RFC 6827 ASON Routing for OSPFv2 Protocols January 2013

6.2. Reachability Advertisement (Local TE Router ID Sub-TLV)

 When an OSPF router is advertising on behalf of multiple transport
 nodes, the routing protocol MUST be able to associate the advertised
 reachability information with the correct transport node.
 For this purpose, a new sub-TLV of the OSPFv2 TE LSA top-level Node
 Attribute TLV is introduced.  This TLV associates the local prefixes
 (see above) to a given transport node identified by the TE Router ID.
 The Type field of the Local TE Router ID sub-TLV is assigned the
 value 5 (see Section 10).  The Length field takes the value 4.  The
 Value field of this sub-TLV contains the Local TE Router Identifier
 encoded over 4 octets.
 The format of the Local TE Router ID sub-TLV is:
  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 (5)          |          Length (4)           |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                 Local TE Router Identifier                    |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 This sub-TLV MUST be included as a sub-TLV of the top-level Node
 Attribute TLV if the OSPF router is advertising on behalf of one or
 more transport nodes having TE Router IDs different from the TE
 Router ID advertised in the Router Address TLV.  For consistency,
 this sub-TLV MUST be included when OSPF is used for the advertisement
 of ASON information as described herein.  If it is not included in a
 Node Attribute TLV, or if a value of 0 is specified for the Local TE
 Router Identifier, the Note Attribute TLV will not be used for
 determining ASON SCN reachability.  Additionally, the condition
 SHOULD be logged for possible action by the network operator.

7. Routing Information Dissemination

 An ASON routing area (RA) represents a partition of the transport
 plane, and its identifier is used within the control plane as the
 representation of this partition.  An RA may contain smaller RAs
 inter-connected by links.  ASON RA levels do not map directly to OSPF
 areas.  Rather, hierarchical levels of RAs are represented by
 separate OSPF protocol instances.  However, it is useful to align the
 RA IDs and area ID in order to facilitate isolation of RAs as
 described in Section 11.1.

Malis, et al. Standards Track [Page 11] RFC 6827 ASON Routing for OSPFv2 Protocols January 2013

 Routing Controllers (RCs) supporting multiple RAs disseminate
 information downward and upward in this ASON hierarchy.  The vertical
 routing information dissemination mechanisms described in this
 section do not introduce or imply hierarchical OSPF areas.  RCs
 supporting RAs at multiple levels are structured as separate OSPF
 instances with routing information exchange between levels described
 by import and export rules between these instances.  The
 functionality described herein does not pertain to OSPF areas or OSPF
 Area Border Router (ABR) functionality.

7.1. Import/Export Rules

 RCs supporting RAs disseminate information upward and downward in the
 hierarchy by importing/exporting routing information as TE LSAs.  TE
 LSAs are area-scoped Opaque LSAs with Opaque type 1 [RFC3630].  The
 information that MAY be exchanged between adjacent levels includes
 the Router Address, Link, and Node Attribute top-level TLVs.
 The imported/exported routing information content MAY be transformed,
 e.g., filtered or aggregated, as long as the resulting routing
 information is consistent.  In particular, when more than one RC is
 bound to adjacent levels and both are allowed to import/export
 routing information, it is expected that these transformations are
 performed in a consistent manner.  Definition of these policy-based
 mechanisms are outside the scope of this document.
 In practice, and in order to avoid scalability and processing
 overhead, routing information imported/exported downward/upward in
 the hierarchy is expected to include reachability information (see
 Section 4) and, upon strict policy control, link topology
 information.

7.2. Loop Prevention

 When more than one RC is bound to an adjacent level of the ASON
 hierarchy and is configured to export routing information upward or
 downward, a specific mechanism is required to avoid looping of
 routing information.  Looping is the re-advertisement of routing
 information into an RA that had previously advertised that routing
 information upward or downward into an upper or lower level RA in the
 ASON hierarchy.  For example, without loop-prevention mechanisms,
 this could happen when the RC advertising routing information
 downward in the hierarchy is not the same one that advertises routing
 information upward in the hierarchy.

Malis, et al. Standards Track [Page 12] RFC 6827 ASON Routing for OSPFv2 Protocols January 2013

7.2.1. Inter-RA Export Upward/Downward Sub-TLVs

 The Inter-RA Export sub-TLVs can be used to prevent the
 re-advertisement of OSPF TE routing information into an RA that
 previously advertised that information.  The type value 13 (see
 Section 10) will indicate that the associated routing information has
 been exported downward.  The type value 12 (see Section 10) will
 indicate that the associated routing information has been exported
 upward.  While it is not required for routing information exported
 downward, both sub-TLVs will include the Routing Area (RA) ID from
 which the routing information was exported.  This RA is not
 necessarily the RA originating the routing information but the RA
 from which the information was immediately exported.
 These additional sub-TLVs MAY be included in TE LSAs that include any
 of the following top-level TLVs:
  1. Router Address top-level TLV
  2. Link top-level TLV
  3. Node Attribute top-level TLV
 The Type field of the Inter-RA Export Upward and Inter-RA Export
 Downward sub-TLVs are respectively assigned the values 12 and 13 (see
 Section 10).  The Length field in these sub-TLVs takes the value 4.
 The Value field in these sub-TLVs contains the associated RA ID.  The
 RA ID value must be a unique identifier for the RA within the ASON
 routing domain.
 The format of the Inter-RA Export Upward and Inter-RA Export Downward
 sub-TLVs is graphically depicted below:
  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
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |       Upward/Downward Type    |           Length (4)          |
 |             (12/13)           |                               |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                       Associated RA ID                        |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

7.2.2. Inter-RA Export Upward/Downward Sub-TLV Processing

 TE LSAs MAY be imported or exported downward or upward in the ASON
 routing hierarchy.  The direction and advertising RA ID are
 advertised in an Inter-RA Export Upward/Downward sub-TLV.  They MUST
 be retained and advertised in the receiving RA with the associated
 routing information.

Malis, et al. Standards Track [Page 13] RFC 6827 ASON Routing for OSPFv2 Protocols January 2013

 When exporting routing information upward in the ASON routing
 hierarchy, any information received from a level above, i.e., tagged
 with an Inter-RA Export Downward sub-TLV, MUST NOT be exported
 upward.  Since an RA at Level N is contained by a single RA at
 Level N+1, this is the only checking that is necessary and the
 associated RA ID is used solely for informational purposes.
 When exporting routing information downward in the ASON routing
 hierarchy, any information received from a level below, i.e., tagged
 with an Inter-RA Export Upward sub-TLV, MUST NOT be exported downward
 if the target RA ID matches the RA ID associated with the routing
 information.  This additional checking is required for routing
 information exported downward since a single RA at Level N+1 may
 contain multiple RAs at Level N in the ASON routing hierarchy.  In
 other words, routing information MUST NOT be exported downward into
 the RA from which it was received.

8. OSPFv2 Scalability

 The extensions described herein are only applicable to ASON routing
 domains, and it is not expected that the attendant reachability (see
 Section 4) and link information will ever be combined with global
 Internet or Layer 3 Virtual Private Network (VPN) routing.  If there
 were ever a requirement for a given RC to participate in both
 domains, separate OSPFv2 instances would be utilized.  However, in a
 multi-level ASON hierarchy, the potential volume of information could
 be quite large and the recommendations in this section MUST be
 followed by RCs implementing this specification.
  1. Routing information exchange upward/downward in the hierarchy

between adjacent RAs MUST, by default, be limited to reachability

   information.  In addition, several transformations such as prefix
   aggregation are RECOMMENDED to reduce the amount of information
   imported/exported by a given RC when such transformations will not
   impact consistency.
  1. Routing information exchange upward/downward in the ASON hierarchy

involving TE attributes MUST be under strict policy control.

   Pacing and min/max thresholds for triggered updates are strongly
   RECOMMENDED.
  1. The number of routing levels MUST be maintained under strict policy

control.

Malis, et al. Standards Track [Page 14] RFC 6827 ASON Routing for OSPFv2 Protocols January 2013

9. Security Considerations

 This document specifies the contents and processing of OSPFv2 TE LSAs
 [RFC3630] and [RFC4202].  The TE LSA extensions defined in this
 document are not used for Shortest Path First (SPF) computation and
 have no direct effect on IP routing.  Additionally, ASON routing
 domains are delimited by the usual administrative domain boundaries.
 Any mechanisms used for securing the exchange of normal OSPF LSAs can
 be applied equally to all TE LSAs used in the ASON context.
 Authentication of OSPFv2 LSA exchanges (such as OSPF cryptographic
 authentication [RFC2328] [RFC5709]) can be used to provide
 significant protection against active attacks.  [RFC5709] defines a
 mechanism for authenticating OSPFv2 packets by making use of the
 Hashed Message Authentication Code (HMAC) algorithm in conjunction
 with the SHA family of cryptographic hash functions.
 RCs implementing export/import of ASON routing information between
 RAs MUST also include policy control of both the maximum amount of
 information advertised between RAs and the maximum rate at which it
 is advertised.  This is to isolate the consequences of an RC being
 compromised to the RAs to which that subverted RC is attached.
 The "Analysis of OSPF Security According to KARP Design Guide"
 [OSPF-SEC] provides a comprehensive analysis of OSPFv2 and OSPFv3
 security relative to the requirements specified in [RFC6518].

10. IANA Considerations

 This document defines new sub-TLVs for inclusion in OSPF TE LSAs.
 IANA has assigned values per the assignment policies for the
 registries of code points for these sub-TLVs [RFC3630].
 The following subsections summarize the required sub-TLVs.

10.1. Sub-TLVs of the Link TLV

 This document defines the following sub-TLVs of the Link TLV
 advertised in the OSPF TE LSA:
  1. Local and Remote TE Router ID sub-TLV (10)
  2. Inter-RA Export Upward sub-TLV (12)
  3. Inter-RA Export Downward sub-TLV (13)
 Codepoints for these sub-TLVs have been allocated in the Standards
 Action range of the "Types for sub-TLVs of TE Link TLV (Value 2)"
 registry [RFC3630].

Malis, et al. Standards Track [Page 15] RFC 6827 ASON Routing for OSPFv2 Protocols January 2013

 Note that the same values for the Inter-RA Export Upward sub-TLV and
 the Inter-RA Export Downward sub-TLV MUST be used when they appear in
 the Link TLV, Node Attribute TLV, and Router Address TLV.

10.2. Sub-TLVs of the Node Attribute TLV

 This document defines the following sub-TLVs of the Node Attribute
 TLV advertised in the OSPF TE LSA:
  1. Local TE Router ID sub-TLV (5)
  2. Inter-RA Export Upward sub-TLV (12)
  3. Inter-RA Export Downward sub-TLV (13)
 Codepoints for these sub-TLVs have been assigned in Standards Action
 range of the "Types for sub-TLVs of TE Node Attribute TLV (Value 5)"
 [RFC5786].
 Note that the same values for the Inter-RA Export Upward sub-TLV and
 the Inter-RA Export Downward sub-TLV MUST be used when they appear in
 the Link TLV, Node Attribute TLV, and Router Address TLV.

10.3. Sub-TLVs of the Router Address TLV

 The Router Address TLV is advertised in the OSPF TE LSA [RFC3630].
 Since the TLV had no sub-TLVs defined, a "Types for sub-TLVs of
 Router Address TLV (Value 1)" registry has been defined.
 The registry guidelines for the assignment of types for sub-TLVs of
 the Router Address TLV are as follows:
    o  Types in the range 0-32767 are to be assigned via Standards
       Action.
    o  Type 0 in the aforementioned Standards Action range (0-32767)
       is reserved.
    o  Types in the range 32768-32777 are for experimental use; these
       will not be registered with IANA and MUST NOT be mentioned by
       RFCs.
    o  Types in the range 32778-65535 are not to be assigned at this
       time.  Before any assignments can be made in this range, there
       MUST be a Standards Track RFC that specifies IANA
       Considerations that covers the range being assigned.

Malis, et al. Standards Track [Page 16] RFC 6827 ASON Routing for OSPFv2 Protocols January 2013

 This document defines the following sub-TLVs for inclusion in the
 Router Address TLV:
  1. Inter-RA Export Upward sub-TLV (12)
  2. Inter-RA Export Downward sub-TLV (13)
 Codepoints for these sub-TLVs have been allocated in the Standards
 Action range of the "Types for sub-TLVs of Router Address TLV
 (Value 1)" registry.
 Note that the same values for the Inter-RA Export Upward sub-TLV and
 the Inter-RA Export Downward sub-TLV MUST be used when they appear in
 the Link TLV, Node Attribute TLV, and Router Address TLV.

11. Management Considerations

11.1. Routing Area (RA) Isolation

 If the RA ID is mapped to the OSPF Area ID as recommended in
 Section 2, OSPF [RFC2328] implicitly provides isolation.  On any
 intra-RA link, packets will only be accepted if the area ID in the
 OSPF packet header matches the area ID for the OSPF interface on
 which the packet was received.  Hence, RCs will only establish
 adjacencies and exchange reachability information (see Section 4.0)
 with RCs in the same RA.  Other mechanisms for RA isolation are
 beyond the scope of this document.

11.2. Routing Area (RA) Topology/Configuration Changes

 The GMPLS Routing for ASON requirements [RFC4258] dictate that the
 routing protocol MUST support reconfiguration and SHOULD support
 architectural evolution.  OSPF [RFC2328] includes support for the
 dynamic introduction or removal of ASON reachability information
 through the flooding and purging of OSPF Opaque LSAs [RFC5250].
 Also, when an RA is partitioned or an RC fails, stale LSAs SHOULD NOT
 be used unless the advertising RC is reachable.  The configuration of
 OSPF RAs and the policies governing the redistribution of ASON
 reachability information between RAs are implementation issues
 outside of the OSPF routing protocol and beyond the scope of this
 document.

12. Comparison to Requirements in RFC 4258

 The following table shows how this document complies with the
 requirements in [RFC4258].  The first column contains a requirements
 number (1-30) and the relevant section in RFC 4258.  The second
 column describes the requirement, the third column discusses the

Malis, et al. Standards Track [Page 17] RFC 6827 ASON Routing for OSPFv2 Protocols January 2013

 compliance to that requirement, and the fourth column lists the
 relevant section in this document and/or another RFC that already
 satisfies the requirement.

Malis, et al. Standards Track [Page 18] RFC 6827 ASON Routing for OSPFv2 Protocols January 2013

+----------+---------------------------+---------------+-------------+
| RFC 4258 |   RFC 4258 Requirement    |  Compliance   |  Reference  |
| Section  |                           |               |             |
|  (Req.   |                           |               |             |
| Number)  |                           |               |             |
+----------+---------------------------+---------------+-------------+
| 3 (1)    | The failure of an RC, or  |  Implied by   |   Not an    |
|          |      the failure of       | separation of |attribute of |
|          |communications between RCs,| transport and |   routing   |
|          |and the subsequent recovery|control plane. |  protocol.  |
|          |from the failure condition |               |             |
|          | MUST NOT disrupt calls in |               |             |
|          |         progress.         |               |             |
+----------+---------------------------+---------------+-------------+
| 3.1 (2)  |   Multiple Hierarchical   |      Yes      | Sections 2  |
|          |  Levels of ASON Routing   |               |    and 3.   |
|          |       Areas (RAs).        |               |             |
+----------+---------------------------+---------------+-------------+
| 3.1 (3)  |   Prior to establishing   | Yes, when RA  |Section 11.1.|
|          | communications, RCs MUST  | maps to OSPF  |             |
|          |verify that they are bound | Area ID.      |             |
|          |  to the same parent RA.   | Otherwise,    |             |
|          |                           | out of scope. |             |
+----------+---------------------------+---------------+-------------+
| 3.1 (4)  | The RC ID MUST be unique  |      Yes      |RFC 2328 and |
|          | within its containing RA. |               | Section 3.  |
+----------+---------------------------+---------------+-------------+
| 3.1 (5)  |Each RA within a carrier's |Yes - although | Sections 2, |
|          | network SHALL be uniquely | uniqueness is | 3, and 11.1.|
|          | identifiable. RA IDs MAY  |the operator's |             |
|          |   be associated with a    |responsibility.|             |
|          |transport-plane name space,|               |             |
|          |    whereas RC IDs are     |               |             |
|          |     associated with a     |               |             |
|          | control-plane name space. |               |             |
+----------+---------------------------+---------------+-------------+
| 3.2 (6)  |   Hierarchical Routing    |      Yes      |  Section 7. |
|          | Information Dissemination.|               |             |
+----------+---------------------------+---------------+-------------+
| 3.2 (7)  |    Routing Information    |      Yes      | Section 7.1.|
|          |exchanged between levels N |               |             |
|          |   and N+1 via separate    |               |             |
|          |       instances and       |               |             |
|          |      import/export.       |               |             |
+----------+---------------------------+---------------+-------------+

Malis, et al. Standards Track [Page 19] RFC 6827 ASON Routing for OSPFv2 Protocols January 2013

+----------+---------------------------+---------------+-------------+
| 3.2 (8)  |    Routing Information    |   No - Not    |             |
|          |exchanged between levels N |  described.   |             |
|          | and N+1 via external link |               |             |
|          |     (inter-RA links).     |               |             |
+----------+---------------------------+---------------+-------------+
| 3.2 (9)  |    Routing information    |      Yes      | Sections 4, |
|          |   exchange MUST include   |               |6, 6.1, 6.2, |
|          | reachability information  |               |    and 8.   |
|          |   and MAY include, upon   |               |             |
|          | policy decision, node and |               |             |
|          |      link topology.       |               |             |
+----------+---------------------------+---------------+-------------+
| 3.2 (10) |  There SHOULD NOT be any  |Yes - separate | Sections 2  |
|          |    dependencies on the    |  instances.   |    and 3.   |
|          |different routing protocols|               |             |
|          |  used within an RA or in  |               |             |
|          |      different RAs.       |               |             |
+----------+---------------------------+---------------+-------------+
| 3.2 (11) |The routing protocol SHALL |      Yes      | Section 7.2.|
|          | differentiate the routing |               |             |
|          |information originated at a|               |             |
|          |given-level RA from derived|               |             |
|          |    routing information    |               |             |
|          |  (received from external  |               |             |
|          |   RAs), even when this    |               |             |
|          |information is forwarded by|               |             |
|          |  another RC at the same   |               |             |
|          |          level.           |               |             |
+----------+---------------------------+---------------+-------------+
| 3.2 (12) | The routing protocol MUST |      Yes      | Section 7.2.|
|          |  provide a mechanism to   |               |             |
|          |    prevent information    |               |             |
|          |propagated from a Level N+1|               |             |
|          | RA's RC into the Level N  |               |             |
|          |    RA's RC from being     |               |             |
|          |  re-introduced into the   |               |             |
|          |    Level N+1 RA's RC.     |               |             |
+----------+---------------------------+---------------+-------------+
| 3.2 (13) | The routing protocol MUST |      Yes      | Section 7.2.|
|          |  provide a mechanism to   |               |             |
|          |    prevent information    |               |             |
|          |propagated from a Level N-1|               |             |
|          | RA's RC into the Level N  |               |             |
|          |    RA's RC from being     |               |             |
|          |  re-introduced into the   |               |             |
|          |    Level N-1 RA's RC.     |               |             |
+----------+---------------------------+---------------+-------------+

Malis, et al. Standards Track [Page 20] RFC 6827 ASON Routing for OSPFv2 Protocols January 2013

+----------+---------------------------+---------------+-------------+
| 3.2 (14) |  Instance of a Level N    |      Yes      | Sections 2, |
|          |  routing function and an  |               |  3, and 7.  |
|          |  instance of a Level N+1  |               |             |
|          |  routing function in the  |               |             |
|          |       same system.        |               |             |
+----------+---------------------------+---------------+-------------+
| 3.2 (15) |    The Level N routing    | Not described |     N/A     |
|          | function is on a separate | but possible. |             |
|          |   system than the Level   |               |             |
|          |   N+1 routing function.   |               |             |
+----------+---------------------------+---------------+-------------+
| 3.3 (16) |The RC MUST support static | The automation| Sections 2  |
|          | (i.e., operator assisted) | requirement is|and 3. Refer |
|          | and MAY support automated | ambiguous.    | to RFC 2328 |
|          |   configuration of the    | OSPF supports |  for OSPF   |
|          |information describing its | auto-discovery|    auto-    |
|          |relationship to its parent | of neighbors  | discovery.  |
|          | and its child within the  | and topology. |             |
|          |  hierarchical structure   | Default and   |             |
|          |  (including RA ID and RC  | automatically |             |
|          |           ID).            | configured    |             |
|          |                           | polices are   |             |
|          |                           | out of scope. |             |
+----------+---------------------------+---------------+-------------+
| 3.3 (17) |The RC MUST support static |Yes - when OSPF|RFC 2328 and |
|          | (i.e., operator assisted) |area maps to RA|Section 11.1.|
|          | and MAY support automated | discovery is  |             |
|          |   configuration of the    |  automatic.   |             |
|          |information describing its |               |             |
|          | associated adjacencies to |               |             |
|          |  other RCs within an RA.  |               |             |
+----------+---------------------------+---------------+-------------+
| 3.3 (18) |The routing protocol SHOULD|      Yes      |  RFC 2328.  |
|          |support all the types of RC|               |             |
|          | adjacencies described in  |               |             |
|          |Section 9 of [G.7715]. The |               |             |
|          | latter includes congruent |               |             |
|          |topology (with distributed |               |             |
|          |  RC) and hubbed topology  |               |             |
|          |(e.g., note that the latter|               |             |
|          |  does not automatically   |               |             |
|          |  imply a designated RC).  |               |             |
+----------+---------------------------+---------------+-------------+

Malis, et al. Standards Track [Page 21] RFC 6827 ASON Routing for OSPFv2 Protocols January 2013

+----------+---------------------------+---------------+-------------+
| 3.4 (19) |The routing protocol SHOULD|      Yes      |RFC 2328, RFC|
|          | be capable of supporting  |               |  5250, and  |
|          |architectural evolution in |               |Section 11.2.|
|          |  terms of the number of   |               |             |
|          |hierarchical levels of RAs,|               |             |
|          |as well as the aggregation |               |             |
|          | and segmentation of RAs.  |               |             |
+----------+---------------------------+---------------+-------------+
|3.5.2 (20)|Advertisements MAY contain |               |             |
|          |the following common set of|               |             |
|          | information regardless of |               |             |
|          | whether they are link or  |               |             |
|          |       node related:       |               |             |
|          |  -  RA ID of the RA to    |      Yes      |  Section    |
|          |     which the             |               |   7.2.1.    |
|          |     advertisement is      |               |             |
|          |     bounded               |               |             |
|          |  -  RC ID of the entity   |      Yes      |  RFC 2328.  |
|          |     generating the        |               |             |
|          |     advertisement         |               |             |
|          |  -  Information to        |      Yes      |RFC 2328, RFC|
|          |     uniquely identify     |               |    5250.    |
|          |     advertisements        |               |             |
|          |  -  Information to        |   No - Must   |             |
|          |     determine whether an  |compare to old.|             |
|          |     advertisement has     |               |             |
|          |     been updated          |               |             |
|          |  -  Information to        |      Yes      |  Section    |
|          |     indicate when an      |               |   7.2.1.    |
|          |     advertisement has been|               |             |
|          |     derived from a        |               |             |
|          |     different level RA.   |               |             |
+----------+---------------------------+---------------+-------------+

Malis, et al. Standards Track [Page 22] RFC 6827 ASON Routing for OSPFv2 Protocols January 2013

+----------+---------------------------+---------------+-------------+
|3.5.3 (21)|The Node Attributes' Node  |Yes - Prefixes |  RFC 5786,  |
|          |ID and Reachability must be|   only for    | Sections 4  |
|          |   advertised. It MAY be   | reachability. |   and 6.    |
|          |  advertised as a set of   |               |             |
|          |associated external (e.g., |               |             |
|          |  User Network Interface   |               |             |
|          |  (UNI)) address/address   |               |             |
|          |   prefixes or a set of    |               |             |
|          |   associated Subnetwork   |               |             |
|          |   Point Pool (SNPP) link  |               |             |
|          | IDs/SNPP ID prefixes, the |               |             |
|          |selection of which MUST be |               |             |
|          |   consistent within the   |               |             |
|          |     applicable scope.     |               |             |
+----------+---------------------------+---------------+-------------+
|3.5.4 (22)| The Link Attributes' Local|      Yes      | Section 6.1.|
|          | SNPP link ID, Remote SNPP |               |             |
|          |link ID, and layer specific|               |             |
|          |  characteristics must be  |               |             |
|          |        advertised.        |               |             |
+----------+---------------------------+---------------+-------------+
|3.5.4 (23)| Link Signaling Attributes |      Yes      | Section 5,  |
|          |other than Local Adaptation|               | RFC 4652 -  |
|          |(Signal Type, Link Weight, |               |  Section    |
|          |  Resource Class, Local    |               |   5.3.1.    |
|          |   Connection Types, Link  |               |             |
|          |      Capacity, Link       |               |             |
|          |   Availability, Diversity |               |             |
|          |          Support).        |               |             |
+----------+---------------------------+---------------+-------------+
|3.5.4 (24)|   Link Signaling Local    |      Yes      | Section 5.1.|
|          |        Adaptation.        |               |             |
+----------+---------------------------+---------------+-------------+
|  5 (25)  |   The routing adjacency   |      Yes      | Sections 2, |
|          |    topology (i.e., the    |               |  3, and 6.  |
|          |associated PC connectivity |               |             |
|          |topology) and the transport|               |             |
|          |network topology SHALL NOT |               |             |
|          |be assumed to be congruent.|               |             |
+----------+---------------------------+---------------+-------------+
|  5 (26)  |The routing topology SHALL |      Yes      |RFC 2328, RFC|
|          |  support multiple links   |               |    3630.    |
|          |  between nodes and RAs.   |               |             |
+----------+---------------------------+---------------+-------------+

Malis, et al. Standards Track [Page 23] RFC 6827 ASON Routing for OSPFv2 Protocols January 2013

+----------+---------------------------+---------------+-------------+
|  5 (27)  |The routing protocol SHALL |      Yes      |RFC 2328, RFC|
|          |  converge such that the   |               |    5250.    |
|          |  distributed Routing      |               |             |
|          |  Databases (RDBs) become  |               |             |
|          |synchronized after a period|               |             |
|          |         of time.          |               |             |
+----------+---------------------------+---------------+-------------+
|  5 (28)  |Self-consistent information|Yes - However, | Section 7.1.|
|          |  at the receiving level   | this is not a |             |
|          |    resulting from any     |    routing    |             |
|          |  transformation (filter,  |   protocol    |             |
|          |   summarize, etc.) and    |   function.   |             |
|          | forwarding of information |               |             |
|          |  from one RC to RC(s) at  |               |             |
|          |   different levels when   |               |             |
|          |multiple RCs are bound to a|               |             |
|          |        single RA.         |               |             |
+----------+---------------------------+---------------+-------------+
|  5 (29)  |    In order to support    |Partial - OSPF |RFC 2328 and |
|          | operator-assisted changes | supports the  |  RFC 5250.  |
|          |    in the containment     |  purging of   |             |
|          | relationships of RAs, the |     stale     |             |
|          |  routing protocol SHALL   |advertisements |             |
|          |support evolution in terms |and origination|             |
|          |     of the number of      |  of new. The  |             |
|          |hierarchical levels of RAs.|non-disruptive |             |
|          |  For example, support of  |  behavior is  |             |
|          | non-disruptive operations |implementation |             |
|          |such as adding and removing|   specific.   |             |
|          | RAs at the top/bottom of  |               |             |
|          | the hierarchy, adding or  |               |             |
|          |  removing a hierarchical  |               |             |
|          |level of RAs in or from the|               |             |
|          |middle of the hierarchy, as|               |             |
|          |  well as aggregation and  |               |             |
|          |   segmentation of RAs.    |               |             |
+----------+---------------------------+---------------+-------------+
|  5 (30)  | A collection of links and |Yes - Within an| Sections 4  |
|          |nodes such as a subnetwork | RA it must be |    and 6.   |
|          |   or RA MUST be able to   |  consistent.  |             |
|          |  represent itself to the  |               |             |
|          | wider network as a single |               |             |
|          | logical entity with only  |               |             |
|          |its external links visible |               |             |
|          | to the topology database. |               |             |
+----------+---------------------------+---------------+-------------+

Malis, et al. Standards Track [Page 24] RFC 6827 ASON Routing for OSPFv2 Protocols January 2013

13. References

13.1. Normative References

 [RFC2119]    Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.
 [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.
 [RFC3945]    Mannie, E., Ed., "Generalized Multi-Protocol Label
              Switching (GMPLS) Architecture", RFC 3945, October 2004.
 [RFC4202]    Kompella, K., Ed., and Y. Rekhter, Ed., "Routing
              Extensions in Support of Generalized Multi-Protocol
              Label Switching (GMPLS)", RFC 4202, October 2005.
 [RFC4203]    Kompella, K., Ed., and Y. Rekhter, Ed., "OSPF Extensions
              in Support of Generalized Multi-Protocol Label Switching
              (GMPLS)", RFC 4203, October 2005.
 [RFC5250]    Berger, L., Bryskin, I., Zinin, A., and R. Coltun, "The
              OSPF Opaque LSA Option", RFC 5250, July 2008.
 [RFC5786]    Aggarwal, R. and K. Kompella, "Advertising a Router's
              Local Addresses in OSPF Traffic Engineering (TE)
              Extensions", RFC 5786, March 2010.

13.2. Informative References

 [RFC4258]    Brungard, D., Ed., "Requirements for Generalized Multi-
              Protocol Label Switching (GMPLS) Routing for the
              Automatically Switched Optical Network (ASON)",
              RFC 4258, November 2005.
 [RFC4652]    Papadimitriou, D., Ed., Ong, L., Sadler, J., Shew, S.,
              and D. Ward, "Evaluation of Existing Routing Protocols
              against Automatic Switched Optical Network (ASON)
              Routing Requirements", RFC 4652, October 2006.
 [RFC5709]    Bhatia, M., Manral, V., Fanto, M., White, R., Barnes,
              M., Li, T., and R. Atkinson, "OSPFv2 HMAC-SHA
              Cryptographic Authentication", RFC 5709, October 2009.

Malis, et al. Standards Track [Page 25] RFC 6827 ASON Routing for OSPFv2 Protocols January 2013

 [RFC6518]    Lebovitz, G. and M. Bhatia, "Keying and Authentication
              for Routing Protocols (KARP) Design Guidelines",
              RFC 6518, February 2012.
 [OSPF-SEC]   Hartman, S. and Zhang, D., "Analysis of OSPF Security
              According to KARP Design Guide", Work in Progress,
              November 2012.
 [G.7715]     ITU-T Rec. G.7715/Y.1706, "Architecture and Requirements
              in the Automatically Switched Optical Network",
              June 2002.
 [G.7715.1]   ITU-T Rec. G.7715.1/Y.1706.1, "ASON Routing Architecture
              and Requirements for Link State Protocols",
              February 2004.
 [G.805]      ITU-T Rec. G.805, "Generic Functional Architecture of
              Transport Networks)", March 2000.
 [G.8080]     ITU-T Rec. G.8080/Y.1304, "Architecture for the
              automatically switched optical network", February 2012.

14. Acknowledgements

 The editors would like to thank Lyndon Ong, Remi Theillaud, Stephen
 Shew, Jonathan Sadler, Deborah Brungard, Lou Berger, and Adrian
 Farrel for their useful comments and suggestions.

14.1. RFC 5787 Acknowledgements

 The author would like to thank Dean Cheng, Acee Lindem, Pandian
 Vijay, Alan Davey, Adrian Farrel, Deborah Brungard, and Ben Campbell
 for their useful comments and suggestions.
 Lisa Dusseault and Jari Arkko provided useful comments during IESG
 review.
 Question 14 of Study Group 15 of the ITU-T provided useful and
 constructive input.

Malis, et al. Standards Track [Page 26] RFC 6827 ASON Routing for OSPFv2 Protocols January 2013

Appendix A. ASON Terminology

 This document makes use of the following terms:
 Administrative domain: (See Recommendation [G.805].)  For the
    purposes of [G.7715.1], an administrative domain represents the
    extent of resources that belong to a single player such as a
    network operator, a service provider, or an end-user.
    Administrative domains of different players do not overlap amongst
    themselves.
 Control plane: performs the call control and connection control
    functions.  Through signaling, the control plane sets up and
    releases connections and may restore a connection in case of a
    failure.
 (Control) Domain: represents a collection of (control) entities that
    are grouped for a particular purpose.  The control plane is
    subdivided into domains matching administrative domains.  Within
    an administrative domain, further subdivisions of the control
    plane are recursively applied.  A routing control domain is an
    abstract entity that hides the details of the RC distribution.
 External NNI (E-NNI): interfaces located between protocol controllers
    between control domains.
 Internal NNI (I-NNI): interfaces located between protocol controllers
    within control domains.
 Link: (See Recommendation G.805.)  A "topological component" that
    describes a fixed relationship between a "subnetwork" or "access
    group" and another "subnetwork" or "access group".  Links are not
    limited to being provided by a single server trail.
 Management plane: performs management functions for the transport
    plane, the control plane, and the system as a whole.  It also
    provides coordination between all the planes.  The following
    management functional areas are performed in the management plane:
    performance, fault, configuration, accounting, and security
    management.
 Management domain: (See Recommendation G.805.)  A management domain
    defines a collection of managed objects that are grouped to meet
    organizational requirements according to geography, technology,
    policy, or other structure, and for a number of functional areas
    such as Fault, Configuration, Accounting, Performance, and
    Security (FCAPS), for the purpose of providing control in a
    consistent manner.  Management domains can be disjoint, contained,

Malis, et al. Standards Track [Page 27] RFC 6827 ASON Routing for OSPFv2 Protocols January 2013

    or overlapping.  As such, the resources within an administrative
    domain can be distributed into several possible overlapping
    management domains.  The same resource can therefore belong to
    several management domains simultaneously, but a management domain
    shall not cross the border of an administrative domain.
 Subnetwork Point (SNP): The SNP is a control-plane abstraction that
    represents an actual or potential transport-plane resource.  SNPs
    (in different subnetwork partitions) may represent the same
    transport resource.  A one-to-one correspondence should not be
    assumed.
 Subnetwork Point Pool (SNPP): A set of SNPs that are grouped together
    for the purposes of routing.
 Termination Connection Point (TCP): A TCP represents the output of a
    Trail Termination function or the input to a Trail Termination
    Sink function.
 Transport plane: provides bidirectional or unidirectional transfer of
    user information, from one location to another.  It can also
    provide transfer of some control and network management
    information.  The transport plane is layered; it is equivalent to
    the Transport Network defined in Recommendation G.805.
 User Network Interface (UNI): interfaces are located between protocol
    controllers between a user and a control domain.  Note: There is
    no routing function associated with a UNI reference point.

Appendix B. ASON Routing Terminology

 This document makes use of the following terms:
 Routing Area (RA): an RA represents a partition of the transport
    plane, and its identifier is used within the control plane as the
    representation of this partition.  Per [G.8080], an RA is defined
    by a set of subnetworks, the links that interconnect them, and the
    interfaces representing the ends of the links exiting that RA.  An
    RA may contain smaller RAs inter-connected by links.  The limit of
    subdivision results in an RA that contains two subnetworks
    interconnected by a single link.
 Routing Database (RDB): a repository for the local topology, network
    topology, reachability, and other routing information that is
    updated as part of the routing information exchange and may
    additionally contain information that is configured.  The RDB may
    contain routing information for more than one routing area (RA).

Malis, et al. Standards Track [Page 28] RFC 6827 ASON Routing for OSPFv2 Protocols January 2013

 Routing Components: ASON routing architecture functions.  These
    functions can be classified as protocol independent (Link Resource
    Manager (LRM), Routing Controller (RC)) or protocol specific
    (Protocol Controller (PC)).
 Routing Controller (RC): handles (abstract) information needed for
    routing and the routing information exchange with peering RCs by
    operating on the RDB.  The RC has access to a view of the RDB.
    The RC is protocol independent.
 Note: Since the RDB may contain routing information pertaining to
    multiple RAs (and possibly to multiple layer networks), the RCs
    accessing the RDB may share the routing information.
 Link Resource Manager (LRM): supplies all the relevant component and
    TE link information to the RC.  It informs the RC about any state
    changes of the link resources it controls.
 Protocol Controller (PC): handles protocol-specific message exchanges
    according to the reference point over which the information is
    exchanged (e.g., E-NNI, I-NNI) and internal exchanges with the RC.
    The PC function is protocol dependent.

Appendix C. Changes from RFC 5787

 This document contains the following changes from RFC 5787:
 1. This document will be on the Standards Track, rather than
    Experimental, and reflects experience gained from RFC 5787
    implementation and interoperability testing.  This also required
    changes to the IANA Considerations.
 2. There is a new Section 3 on Terminology and Identification to
    describe the mapping of key ASON entities to OSPF entities.
 3. Sections were reorganized to explain terminology before defining
    prefix extensions.
 4. There is a new Section 11, Management Considerations, which
    describes how existing OSPF mechanisms address ASON requirements
    on Routing Area changes.
 5. There is a new Section 12, which compares the document to the
    requirements in RFC 4258.
 6. The prefix format was changed to reference RFC 5786 rather than
    defining a separate format and The Node Attribute TLV in RFC 5786
    has been updated as a result.

Malis, et al. Standards Track [Page 29] RFC 6827 ASON Routing for OSPFv2 Protocols January 2013

 7. Routing Information Advertisements were simplified from RFC 5787.
 8. Review comments from ITU-T SG15 and the IESG were incorporated.

Authors' Addresses

 Andrew G. Malis
 Verizon Communications
 60 Sylvan Rd.
 Waltham, MA 02451 USA
 EMail: andrew.g.malis@verizon.com
 Acee Lindem
 Ericsson
 102 Carric Bend Court
 Cary, NC 27519
 EMail: acee.lindem@ericsson.com
 Dimitri Papadimitriou
 Alcatel-Lucent
 Copernicuslaan, 50
 2018 Antwerpen, Belgium
 EMail: dimitri.papadimitriou@alcatel-lucent.com

Malis, et al. Standards Track [Page 30]

/data/webs/external/dokuwiki/data/pages/rfc/rfc6827.txt · Last modified: 2013/01/10 22:05 by 127.0.0.1

Donate Powered by PHP Valid HTML5 Valid CSS Driven by DokuWiki