OSPFv3

Summarization is often used in multi-area or multi-domain networks to improve network efficiency and scalability. With summarization in place, there is a need to signal loss of reachability to an individual prefix covered by the summary. This enables fast convergence by steering traffic, when applicable, away from the node which owns the prefix and is no longer reachable.

This document specifies protocol mechanisms in IS-IS and OSPF, together with two new flags, to advertise such prefix reachability loss.

The term "OSPF" in this document is used to refer to both OSPFv2 and OSPFv3.

Each OSPF prefix can be advertised with an 8-bit field to indicate specific properties of that prefix. However, all the OSPFv3 Prefix Options bits have already been assigned, and only a few bits remain unassigned in the Flags field of the OSPFv2 Extended Prefix TLV.

This document solves this problem by defining a variable-length Prefix Extended Flags sub-TLV for OSPF. This sub-TLV is applicable to OSPFv2 and OSPFv3.

Routing with link-state protocols in dense network topologies can result in suboptimal convergence times due to the overhead associated with flooding. This can be addressed by decreasing the flooding topology so that it is less dense.

This document discusses the problem in some depth and an architectural solution. Specific protocol changes for IS-IS, OSPFv2, and OSPFv3 are described in this document.

This document defines a YANG data model augmenting the IETF OSPF YANG data model (RFC 9129) to provide support for OSPFv3 Link State Advertisement (LSA) Extensibility as defined in RFC 8362. OSPFv3 Extended LSAs provide extensible TLV-based LSAs for the base LSA types defined in RFC 5340.

The Segment Routing (SR) architecture allows a flexible definition of the end-to-end path by encoding it as a sequence of topological elements called segments. It can be implemented over an MPLS or IPv6 data plane. This document describes the OSPFv3 extensions required to support SR over the IPv6 data plane.

Flexible Algorithm is a solution that allows some routing protocols (e.g., OSPF and IS-IS) to compute paths over a network based on user-defined (and hence, flexible) constraints and metrics. The computation is performed by routers participating in the specific network in a distributed manner using a Flexible Algorithm Definition (FAD). This definition is provisioned on one or more routers and propagated through the network by OSPF and IS-IS flooding.

Border Gateway Protocol - Link State (BGP-LS) enables the collection of various topology information from the network. This document defines extensions to the BGP-LS address family to advertise the FAD as a part of the topology information from the network.

Extensions have been defined for link-state routing protocols that enable distribution of application-specific link attributes for existing as well as newer applications such as Segment Routing (SR). This document defines extensions to the Border Gateway Protocol - Link State (BGP-LS) to enable the advertisement of these application-specific attributes as a part of the topology information from the network.

Seamless Bidirectional Forwarding Detection (S-BFD) defines a simplified mechanism to use Bidirectional Forwarding Detection (BFD) with large portions of negotiation aspects eliminated, thus providing benefits such as quick provisioning as well as improved control and flexibility to network nodes initiating the path monitoring. The link-state routing protocols (IS-IS and OSPF) have been extended to advertise the S-BFD Discriminators.

This document defines extensions to the BGP - Link State (BGP-LS) address family to carry the S-BFD Discriminators' information via BGP.

IANA has created "Protocol in the Segment ID Sub-TLV" and "Protocol in Label Stack Sub-TLV of Downstream Detailed Mapping TLV" registries under the "Multiprotocol Label Switching (MPLS) Label Switched Paths (LSPs) Ping Parameters" registry. RFC 8287 defines the code points for Open Shortest Path First (OSPF) and Intermediate System to Intermediate System (IS-IS) protocols.

This document specifies the code point to be used in the Segment ID sub-TLV and Downstream Detailed Mapping (DDMAP) TLV when the Interior Gateway Protocol (IGP) is OSPFv3. This document also updates RFC 8287 by clarifying that the existing "OSPF" code point is to be used only to indicate OSPFv2 and by defining the behavior when the Segment ID sub-TLV indicates the use of IPv6.

Segment Routing (SR) allows for a flexible definition of end-to-end paths by encoding paths as sequences of topological subpaths, called "segments". These segments are advertised by routing protocols, e.g., by the link-state routing protocols (IS-IS, OSPFv2, and OSPFv3) within IGP topologies.

This document defines extensions to the Border Gateway Protocol - Link State (BGP-LS) address family in order to carry SR information via BGP.

Segment Routing (SR) allows a flexible definition of end-to-end paths within IGP topologies by encoding paths as sequences of topological subpaths called "segments". These segments are advertised by the link-state routing protocols (IS-IS and OSPF).

This document describes the OSPFv3 extensions required for Segment Routing with the MPLS data plane.

OSPFv3 requires functional extension beyond what can readily be done with the fixed-format Link State Advertisement (LSA) as described in RFC 5340. Without LSA extension, attributes associated with OSPFv3 links and advertised IPv6 prefixes must be advertised in separate LSAs and correlated to the fixed-format LSAs. This document extends the LSA format by encoding the existing OSPFv3 LSA information in Type-Length-Value (TLV) tuples and allowing advertisement of additional information with additional TLVs. Backward-compatibility mechanisms are also described.

This document updates RFC 5340, "OSPF for IPv6", and RFC 5838, "Support of Address Families in OSPFv3", by providing TLV-based encodings for the base OSPFv3 unicast support and OSPFv3 address family support.

This document defines a mechanism to use IPv4 to transport OSPFv3 packets. Using OSPFv3 over IPv4 with the existing OSPFv3 Address Family extension can simplify transition from an OSPFv2 IPv4-only routing domain to an OSPFv3 dual-stack routing domain. This document updates RFC 5838 to support virtual links in the IPv4 unicast address family when using OSPFv3 over IPv4.

It is useful for routers in an OSPFv2 or OSPFv3 routing domain to know the capabilities of their neighbors and other routers in the routing domain. This document proposes extensions to OSPFv2 and OSPFv3 for advertising optional router capabilities. The Router Information (RI) Link State Advertisement (LSA) is defined for this purpose. In OSPFv2, the RI LSA will be implemented with an Opaque LSA type ID. In OSPFv3, the RI LSA will be implemented with a unique LSA type function code. In both protocols, the RI LSA can be advertised at any of the defined flooding scopes (link, area, or autonomous system (AS)). This document obsoletes RFC 4970 by providing a revised specification that includes support for advertisement of multiple instances of the RI LSA and a TLV for functional capabilities.

OSPFv3 is a candidate for deployments in environments where autoconfiguration is a requirement. One such environment is the IPv6 home network where users expect to simply plug in a router and have it automatically use OSPFv3 for intra-domain routing. This document describes the necessary mechanisms for OSPFv3 to be self-configuring. This document updates RFC 5340 by relaxing the HelloInterval/ RouterDeadInterval checking during OSPFv3 adjacency formation and adding hysteresis to the update of self-originated Link State Advertisements (LSAs).

Currently, OSPF for IPv6 (OSPFv3) uses IPsec as the only mechanism for authenticating protocol packets. This behavior is different from authentication mechanisms present in other routing protocols (OSPFv2, Intermediate System to Intermediate System (IS-IS), RIP, and Routing Information Protocol Next Generation (RIPng)). In some environments, it has been found that IPsec is difficult to configure and maintain and thus cannot be used. This document defines an alternative mechanism to authenticate OSPFv3 protocol packets so that OSPFv3 does not depend only upon IPsec for authentication.

The OSPFv3 Authentication Trailer was originally defined in RFC 6506. This document obsoletes RFC 6506 by providing a revised definition, including clarifications and refinements of the procedures.

This document modifies the "Unassigned" number space in the IANA "OSPFv3 Instance ID Address Family Values" registry by dividing it in two halves -- one half Unassigned but managed via Standards Action, and the other Reserved for Private Use. It updates RFC 5838.

Many Service Providers (SPs) offer Virtual Private Network (VPN) services to their customers using a technique in which Customer Edge (CE) routers are routing peers of Provider Edge (PE) routers. The Border Gateway Protocol (BGP) is used to distribute the customer's routes across the provider's IP backbone network, and Multiprotocol Label Switching (MPLS) is used to tunnel customer packets across the provider's backbone. Support currently exists for both IPv4 and IPv6 VPNs; however, only Open Shortest Path First version 2 (OSPFv2) as PE-CE protocol is specified. This document extends those specifications to support OSPF version 3 (OSPFv3) as a PE-CE routing protocol. The OSPFv3 PE-CE functionality is identical to that of OSPFv2 except for the differences described in this document. [STANDARDS-TRACK]

This document describes a mechanism for supporting multiple address families (AFs) in OSPFv3 using multiple instances. It maps an AF to an OSPFv3 instance using the Instance ID field in the OSPFv3 packet header. This approach is fairly simple and minimizes extensions to OSPFv3 for supporting multiple AFs. [STANDARDS-TRACK]

This memo defines a portion of the Management Information Base (MIB) for use with network management protocols in IPv6-based internets. In particular, it defines objects for managing the Open Shortest Path First (OSPF) Routing Protocol for IPv6, otherwise known as OSPF version 3 (OSPFv3). [STANDARDS-TRACK]

This document defines an OSPFv3-based (Open Shortest Path First version 3) Layer 1 Virtual Private Network (L1VPN) auto-discovery mechanism. This document parallels the existing OSPF version 2 L1VPN auto-discovery mechanism. The notable functional difference is the support of IPv6. This memo defines an Experimental Protocol for the Internet community.

This document describes extensions to OSPFv3 to support intra-area Traffic Engineering (TE). This document extends OSPFv2 TE to handle IPv6 networks. A new TLV and several new sub-TLVs are defined to support IPv6 networks. [STANDARDS-TRACK]

This document describes the modifications to OSPF to support version 6 of the Internet Protocol (IPv6). The fundamental mechanisms of OSPF (flooding, Designated Router (DR) election, area support, Short Path First (SPF) calculations, etc.) remain unchanged. However, some changes have been necessary, either due to changes in protocol semantics between IPv4 and IPv6, or simply to handle the increased address size of IPv6. These modifications will necessitate incrementing the protocol version from version 2 to version 3. OSPF for IPv6 is also referred to as OSPF version 3 (OSPFv3).

Changes between OSPF for IPv4, OSPF Version 2, and OSPF for IPv6 as described herein include the following. Addressing semantics have been removed from OSPF packets and the basic Link State Advertisements (LSAs). New LSAs have been created to carry IPv6 addresses and prefixes. OSPF now runs on a per-link basis rather than on a per-IP-subnet basis. Flooding scope for LSAs has been generalized. Authentication has been removed from the OSPF protocol and instead relies on IPv6's Authentication Header and Encapsulating Security Payload (ESP).

Even with larger IPv6 addresses, most packets in OSPF for IPv6 are almost as compact as those in OSPF for IPv4. Most fields and packet- size limitations present in OSPF for IPv4 have been relaxed. In addition, option handling has been made more flexible.

All of OSPF for IPv4's optional capabilities, including demand circuit support and Not-So-Stubby Areas (NSSAs), are also supported in OSPF for IPv6. [STANDARDS-TRACK]

This document describes the OSPFv3 graceful restart. The OSPFv3 graceful restart is identical to that of OSPFv2 except for the differences described in this document. These differences include the format of the grace Link State Advertisements (LSAs) and other considerations. [STANDARDS-TRACK]

This document describes means and mechanisms to provide authentication/confidentiality to OSPFv3 using an IPv6 Authentication Header/Encapsulating Security Payload (AH/ESP) extension header. [STANDARDS-TRACK]