TRILL

Explicit Congestion Notification (ECN) allows a forwarding element to notify downstream devices, including the destination, of the onset of congestion without having to drop packets. This can improve network efficiency through better congestion control without packet drops. This document extends ECN to TRansparent Interconnection of Lots of Links (TRILL) switches, including integration with IP ECN, and provides for ECN marking in the TRILL header extension flags word (RFC 7179).

A major issue in multilevel TRILL is how to manage RBridge nicknames. In this document, area border RBridges use a single nickname in both Level 1 and Level 2. RBridges in Level 2 must obtain unique nicknames but RBridges in different Level 1 areas may have the same nicknames.

Point-to-multipoint (P2MP) Bidirectional Forwarding Detection (BFD) is designed to verify multipoint connectivity. This document specifies the support of P2MP BFD in Transparent Interconnection of Lots of Links (TRILL). Similar to TRILL point-to-point BFD, BFD Control packets in TRILL P2MP BFD are transmitted using RBridge Channel messages. This document updates RFCs 7175 and 7177.

This document specifies extensions to the IETF TRILL (Transparent Interconnection of Lots of Links) protocol to support multi-topology routing of unicast and multi-destination traffic based on IS-IS (Intermediate System to Intermediate System) multi-topology specified in RFC 5120. This document updates RFCs 6325 and 7177.

This document addresses the problem of the size and freshness of the endnode learning table in edge Routing Bridges (RBridges), by allowing endnodes to volunteer for endnode learning and encapsulation/decapsulation. Such an endnode is known as a "Smart Endnode". Only the attached edge RBridge can distinguish a "Smart Endnode" from a "normal endnode". The Smart Endnode uses the nickname of the attached edge RBridge, so this solution does not consume extra nicknames. The solution also enables endnodes that are Fine-Grained Label (FGL) aware.

This document specifies methods to interconnect multiple TRILL (Transparent Interconnection of Lots of Links) sites with an intervening MPLS network using existing TRILL and VPLS (Virtual Private LAN Service) standards. This document addresses two problems: 1) providing connection between more than two TRILL sites that are separated by an MPLS provider network and 2) providing a single logical virtualized TRILL network for different tenants that are separated by an MPLS provider network.

The TRILL (Transparent Interconnection of Lots of Links) protocol, by default, learns end station addresses from observing the data plane. In particular, it learns local Media Access Control (MAC) addresses and the edge switch port of attachment from the receipt of local data frames and learns remote MAC addresses and the edge switch port of attachment from the decapsulation of remotely sourced TRILL Data packets.

This document specifies a message by which a TRILL switch can explicitly request other TRILL switches to flush certain MAC reachability learned through the decapsulation of TRILL Data packets. This is a supplement to the TRILL automatic address forgetting (see Section 4.8.3 of RFC 6325) and can assist in achieving more rapid convergence in case of topology or configuration change.

TRILL (Transparent Interconnection of Lots of Links) routing can be extended to support multiple levels by building on the multilevel feature of IS-IS routing. Depending on how nicknames are managed, there are two primary alternatives to realize TRILL multilevel: the unique nickname approach and the aggregated nickname approach as discussed in RFC 8243. This document specifies a unique nickname approach. This approach gives unique nicknames to all TRILL switches across the multilevel TRILL campus.

This document describes how data center networks can benefit from non-RBridge nodes performing TRILL (Transparent Interconnection of Lots of Links) encapsulation with assistance from a directory service.

The IETF TRILL (Transparent Interconnection of Lots of Links) protocol is implemented by devices called TRILL switches or RBridges (Routing Bridges). TRILL includes a general mechanism, called an RBridge Channel, for the transmission of typed messages between RBridges in the same campus and between RBridges and end stations on the same link. This document specifies a method to send vendor-specific messages over the RBridge Channel facility.

In Transparent Interconnection of Lots of Links (TRILL) active-active access, a Reverse Path Forwarding (RPF) check failure issue may occur when using the pseudo-nickname mechanism specified in RFC 7781. This document describes a solution to resolve this RPF check failure issue through centralized replication. All ingress Routing Bridges (RBridges) send Broadcast, Unknown Unicast, and Multicast (BUM) traffic to a centralized node with unicast TRILL encapsulation. When the centralized node receives the BUM traffic, it decapsulates the packets and forwards them to their destination RBridges using a distribution tree established per the TRILL base protocol (RFC 6325). To avoid RPF check failure on an RBridge sitting between the ingress RBridge and the centralized replication node, some change in the RPF calculation algorithm is required. RPF checks on each RBridge MUST be calculated as if the centralized node was the ingress RBridge, instead of being calculated using the actual ingress RBridge. This document updates RFC 6325.

This document describes mechanisms to optimize the Address Resolution Protocol (ARP) and Neighbor Discovery (ND) traffic in a Transparent Interconnection of Lots of Links (TRILL) campus. TRILL switches maintain a cache of IP / Media Access Control (MAC) address / Data Label bindings that are learned from ARP/ND requests and responses that pass through them. In many cases, this cache allows an edge Routing Bridge (RBridge) to avoid flooding an ARP/ND request by either responding to it directly or encapsulating it and unicasting it. Such optimization reduces packet flooding over a TRILL campus.

The base IETF TRILL (Transparent Interconnection of Lots of Links) protocol has a TRILL campus-wide MTU feature, specified in RFCs 6325 and 7177, that assures that link-state changes can be successfully flooded throughout the campus while being able to take advantage of a campus-wide capability to support jumbo packets. This document specifies recommended updates to that MTU feature to take advantage, for appropriate link-local packets, of link-local MTUs that exceed the TRILL campus MTU. In addition, it specifies an efficient algorithm for local MTU testing. This document updates RFCs 6325, 7177, and 7780.

Although TRILL is based on IS-IS, which supports multilevel unicast routing, extending TRILL to multiple levels has challenges that are not addressed by the already-existing capabilities of IS-IS. One issue is with the handling of multi-destination packet distribution trees. Other issues are with TRILL switch nicknames. How are such nicknames allocated across a multilevel TRILL network? Do nicknames need to be unique across an entire multilevel TRILL network? Or can they merely be unique within each multilevel area?

This informational document enumerates and examines alternatives based on a number of factors including backward compatibility, simplicity, and scalability; it makes recommendations in some cases.

This document describes mechanisms for providing directory service to TRILL (Transparent Interconnection of Lots of Links) edge switches. The directory information provided can be used in reducing multi-destination traffic, particularly ARP / Neighbor Discovery (ND) and unknown unicast flooding. It can also be used to detect traffic with forged source addresses.

TRILL (Transparent Interconnection of Lots of Links) supports multi-access LAN (Local Area Network) links where a single link can have multiple end stations and TRILL switches attached. Where multiple TRILL switches are attached to a link, native traffic to and from end stations on that link is handled by a subset of those TRILL switches called "Appointed Forwarders" as originally specified in RFC 6325, with the intent that native traffic in each VLAN be handled by at most one TRILL switch. This document clarifies and updates the Appointed Forwarder mechanism. It updates RFCs 6325 and 7177 and obsoletes RFC 6439.

The IETF TRILL (Transparent Interconnection of Lots of Links) protocol includes an optional mechanism (specified in RFC 7178) called RBridge Channel for the transmission of typed messages between TRILL switches in the same campus and the transmission of such messages between TRILL switches and end stations on the same link. This document specifies extensions to the RBridge Channel protocol header to support two features as follows: (1) a standard method to tunnel payloads whose type can be indicated by Ethertype through encapsulation in RBridge Channel messages; and (2) a method to support security facilities for RBridge Channel messages. This document updates RFC 7178.

The base TRILL (Transparent Interconnection of Lots of Links) protocol provides optimal pair-wise data frame forwarding for Layer 2 intra-subnet traffic but not for Layer 3 inter-subnet traffic. A centralized gateway solution is typically used for Layer 3 inter-subnet traffic forwarding but has the following issues:

1. Sub-optimum forwarding paths for inter-subnet traffic.

2. A centralized gateway that may need to support a very large number of gateway interfaces in a Data Center, one per tenant per Data Label used by that tenant, to provide interconnect functionality for all the Layer 2 Virtual Networks in a TRILL campus.

3. A traffic bottleneck at the gateway.

This document specifies an optional TRILL distributed gateway solution that resolves these centralized gateway issues.

TRILL (Transparent Interconnection of Lots of Links) uses distribution trees to deliver multi-destination frames. Multiple trees can be used by an ingress Routing Bridge (RBridge) for flows, regardless of the VLAN, Fine-Grained Label (FGL), and/or multicast group of the flow. Different ingress RBridges may choose different distribution trees for TRILL Data packets in the same VLAN, FGL, and/or multicast group. To avoid unnecessary link utilization, distribution trees should be pruned based on one or more of the following: VLAN, FGL, or multicast destination address. If any VLAN, FGL, or multicast group can be sent on any tree, for typical fast-path hardware, the amount of pruning information is multiplied by the number of trees, but there is limited hardware capacity for such pruning information.

This document specifies an optional facility to restrict the TRILL Data packets sent on particular distribution trees by VLAN, FGL, and/or multicast groups, thus reducing the total amount of pruning information so that it can more easily be accommodated by fast-path hardware.

This document specifies a TRILL (Transparent Interconnection of Lots of Links) IS-IS application sub-TLV that enables the reporting by a TRILL switch of sets of addresses. Each set of addresses reports all of the addresses that designate the same interface (port) and also reports the TRILL switch by which that interface is reachable. For example, a 48-bit MAC (Media Access Control) address, IPv4 address, and IPv6 address can be reported as all corresponding to the same interface reachable by a particular TRILL switch. Such information could be used in some cases to synthesize responses to, or bypass the need for, the Address Resolution Protocol (ARP), the IPv6 Neighbor Discovery (ND) protocol, or the flooding of unknown MAC addresses.

This document specifies the MIB for the OAM (Operations, Administration, and Maintenance) objects for IETF TRILL (Transparent Interconnection of Lots of Links).

Since the publication of the TRILL (Transparent Interconnection of Lots of Links) base protocol in 2011, active development and deployment of TRILL have revealed errata in RFC 6325 and areas that could use clarifications or updates. RFC 7177, RFC 7357, and an intended replacement of RFC 6439 provide clarifications and updates with respect to adjacency, the TRILL ESADI (End Station Address Distribution Information) protocol, and Appointed Forwarders, respectively. This document provides other known clarifications, corrections, and updates. It obsoletes RFC 7180 (the previous "TRILL clarifications, corrections, and updates" RFC), and it updates RFCs 6325, 7177, and 7179.

The IETF TRILL (Transparent Interconnection of Lots of Links) protocol provides support for flow-level multipathing for both unicast and multi-destination traffic in networks with arbitrary topology. Active-active access at the TRILL edge is the extension of these characteristics to end stations that are multiply connected to a TRILL campus as discussed in RFC 7379. In this document, the edge RBridge (Routing Bridge, or TRILL switch) group providing active-active access to such an end station is represented as a virtual RBridge. Based on the concept of the virtual RBridge, along with its pseudo-nickname, this document specifies a method for TRILL active-active access by such end stations.

TRILL (Transparent Interconnection of Lots of Links) active-active service provides end stations with flow-level load balance and resilience against link failures at the edge of TRILL campuses, as described in RFC 7379.

This document specifies a method by which member RBridges (also referred to as Routing Bridges or TRILL switches) in an active-active edge RBridge group use their own nicknames as ingress RBridge nicknames to encapsulate frames from attached end systems. Thus, remote edge RBridges (who are not in the group) will see one host Media Access Control (MAC) address being associated with the multiple RBridges in the group. Such remote edge RBridges are required to maintain all those associations (i.e., MAC attachments) and to not flip-flop among them (as would occur prior to the implementation of this specification). The design goals of this specification are discussed herein.

TRILL (Transparent Interconnection of Lots of Links) facilitates loop-free connectivity to non-TRILL networks via a choice of an Appointed Forwarder for a set of VLANs. Appointed Forwarders provide VLAN-based load sharing with an active-standby model. High-performance applications require an active-active load-sharing model. The active-active load-sharing model can be accomplished by representing any given non-TRILL network with a single virtual RBridge (also referred to as a virtual Routing Bridge or virtual TRILL switch). Virtual representation of the non-TRILL network with a single RBridge poses serious challenges in multi-destination RPF (Reverse Path Forwarding) check calculations. This document specifies required enhancements to build Coordinated Multicast Trees (CMT) within the TRILL campus to solve related RPF issues. CMT, which only requires a software upgrade, provides flexibility to RBridges in selecting a desired path of association to a given TRILL multi-destination distribution tree. This document updates RFC 6325.

This document specifies Transparent Interconnection of Lots of Links (TRILL) Operations, Administration, and Maintenance (OAM) fault management. Methods in this document follow the CFM (Connectivity Fault Management) framework defined in IEEE 802.1 and reuse OAM tools where possible. Additional messages and TLVs are defined for TRILL-specific applications or for cases where a different set of information is required other than CFM as defined in IEEE 802.1. This document updates RFC 6325.

Performance Monitoring (PM) is a key aspect of Operations, Administration, and Maintenance (OAM). It allows network operators to verify the Service Level Agreement (SLA) provided to customers and to detect network anomalies. This document specifies mechanisms for Loss Measurement and Delay Measurement in Transparent Interconnection of Lots of Links (TRILL) networks.

The IETF TRILL (Transparent Interconnection of Lots of Links) protocol provides support for flow-level multipathing with rapid failover for both unicast and multi-destination traffic in networks with arbitrary topology. Active-active connection at the TRILL edge is the extension of these characteristics to end stations that are multiply connected to a TRILL campus. This informational document discusses the high-level problems and goals when providing active-active connection at the TRILL edge.

The IETF TRILL (Transparent Interconnection of Lots of Links) protocol provides least-cost pair-wise data forwarding without configuration in multi-hop networks with arbitrary topologies and link technologies. TRILL supports multipathing of both unicast and multicast traffic. Devices that implement the TRILL protocol are called TRILL switches or RBridges (Routing Bridges).

ESADI (End Station Address Distribution Information) is an optional protocol by which a TRILL switch can communicate, in a Data Label (VLAN or fine-grained label) scoped way, end station address and reachability information to TRILL switches participating in ESADI for the relevant Data Label. This document updates RFC 6325, specifically the documentation of the ESADI protocol, and is not backwards compatible.

IEEE 802.1 has specified Connectivity Fault Management (CFM) Operations, Administration, and Maintenance (OAM) facilities. CFM messages are structured with an OpCode field and have provision for the inclusion of TLV-structured information. IEEE 802.1 has allocated blocks of CFM OpCodes and TLV Types to the IETF. This document specifies the IANA considerations for the assignment of values from these blocks.

The IETF has standardized Transparent Interconnection of Lots of Links (TRILL), a protocol for least-cost transparent frame routing in multi-hop networks with arbitrary topologies and link technologies, using link-state routing and a hop count. The TRILL base protocol standard supports the labeling of TRILL Data packets with up to 4K IDs. However, there are applications that require a larger number of labels providing configurable isolation of data. This document updates RFC 6325 by specifying optional extensions to the TRILL base protocol to safely accomplish this. These extensions, called fine-grained labeling, are primarily intended for use in large data centers, that is, those with more than 4K users requiring configurable data isolation from each other.

This document specifies how to interconnect a pair of Transparent Interconnection of Lots of Links (TRILL) switch ports using pseudowires under existing TRILL and Pseudowire Emulation End-to-End (PWE3) standards.

This document specifies a reference framework for Operations, Administration, and Maintenance (OAM) in Transparent Interconnection of Lots of Links (TRILL) networks. The focus of the document is on the fault and performance management aspects of TRILL OAM.

This document specifies use of the Bidirectional Forwarding Detection (BFD) protocol in Routing Bridge (RBridge) campuses based on the RBridge Channel extension to the Transparent Interconnection of Lots of Links (TRILL) protocol.

BFD is a widely deployed Operations, Administration, and Maintenance (OAM) mechanism in IP and MPLS networks, using UDP and Associated Channel Header (ACH) encapsulation respectively. This document specifies the BFD encapsulation over TRILL.

The IETF Transparent Interconnection of Lots of Links (TRILL) protocol provides optimal pair-wise data frame forwarding without configuration in multi-hop networks with arbitrary topology and link technology; it also provides support for multipathing of both unicast and multicast traffic. This document specifies the data formats and code points for the IS-IS extensions to support TRILL. These data formats and code points may also be used by technologies other than TRILL. This document obsoletes RFC 6326.

The IETF Transparent Interconnection of Lots of Links (TRILL) protocol supports arbitrary link technologies between TRILL switches, including point-to-point links and multi-access Local Area Network (LAN) links that can have multiple TRILL switches and end stations attached. TRILL uses Intermediate System to Intermediate System (IS-IS) routing. This document specifies the establishment, reporting, and termination of IS-IS adjacencies between TRILL switches, also known as RBridges (Routing Bridges). It also concerns four other link-local aspects of TRILL: Designated RBridge (DRB) selection, MTU (Maximum Transmission Unit) testing, pseudonode creation, and BFD (Bidirectional Forwarding Detection) session bootstrapping in connection with adjacency. State diagrams are included where appropriate. This document obsoletes RFC 6327 and updates RFC 6325.

This document specifies a general channel mechanism for sending messages, such as Bidirectional Forwarding Detection (BFD) messages, between Routing Bridges (RBridges) and between RBridges and end stations in an RBridge campus through extensions to the Transparent Interconnection of Lots of Links (TRILL) protocol.

The IETF Transparent Interconnection of Lots of Links (TRILL) base protocol (RFC 6325) specifies minimal hooks to safely support TRILL Header extensions. This document specifies an initial extension providing additional flag bits and specifies some of those bits. It updates RFC 6325.

Edge TRILL (Transparent Interconnection of Lots of Links) switches currently learn the mapping between MAC (Media Access Control) addresses and their egress TRILL switch by observing the data packets they ingress or egress or by the TRILL ESADI (End-Station Address Distribution Information) protocol. When an ingress TRILL switch receives a data frame for a destination address (MAC&Label) that the switch does not know, the data frame is flooded within the frame's Data Label across the TRILL campus.

This document describes the framework for using directory services to assist edge TRILL switches in reducing multi-destination frames, particularly unknown unicast frames flooding, and ARP/ND (Address Resolution Protocol / Neighbor Discovery), thus improving TRILL network scalability and security.

Operations, Administration, and Maintenance (OAM) is a general term used to identify functions and toolsets to troubleshoot and monitor networks. This document presents OAM requirements applicable to the Transparent Interconnection of Lots of Links (TRILL).

This memo defines a portion of the Management Information Base (MIB) for use with network management protocols. In particular, it defines objects for managing a Routing Bridge (RBridge), also known as a TRILL Switch, based on the IETF TRILL (Transparent Interconnection of Lots of Links) protocol. [STANDARDS-TRACK]

Fibre Channel over Ethernet (FCoE) and Transparent Interconnection of Lots of Links (TRILL) are two emerging standards in the data center environment. While these two protocols are seemingly unrelated, they have a very similar behavior in the forwarding plane, as both perform hop-by-hop forwarding over Ethernet, modifying the packet's Media Access Control (MAC) addresses at each hop. This document describes an architecture for the integrated deployment of these two protocols. This document is not an Internet Standards Track specification; it is published for informational purposes.

The Point-to-Point Protocol (PPP) defines a Link Control Protocol (LCP) and a method for negotiating the use of multiprotocol traffic over point-to-point links. This document describes PPP support for the Transparent Interconnection of Lots of Links (TRILL) Protocol, allowing direct communication between Routing Bridges (RBridges) via PPP links. [STANDARDS-TRACK]

Routing Bridges (RBridges) provide optimal pair-wise forwarding without configuration, safe forwarding even during periods of temporary loops, and support for multipathing of both unicast and multicast traffic. They achieve these goals using IS-IS routing and encapsulation of traffic with a header that includes a hop count.

RBridges are compatible with previous IEEE 802.1 customer bridges as well as IPv4 and IPv6 routers and end nodes. They are as invisible to current IP routers as bridges are and, like routers, they terminate the bridge spanning tree protocol.

The design supports VLANs and the optimization of the distribution of multi-destination frames based on VLAN ID and based on IP-derived multicast groups. It also allows unicast forwarding tables at transit RBridges to be sized according to the number of RBridges (rather than the number of end nodes), which allows their forwarding tables to be substantially smaller than in conventional customer bridges. [STANDARDS-TRACK]

Current IEEE 802.1 LANs use spanning tree protocols that have a number of challenges. These protocols need to strictly avoid loops, even temporary ones, during route propagation, because of the lack of header loop detection support. Routing tends not to take full advantage of alternate paths, or even non-overlapping pairwise paths (in the case of spanning trees). This document addresses these concerns and suggests applying modern network-layer routing protocols at the link layer. This document assumes that solutions would not address issues of scalability beyond that of existing IEEE 802.1 bridged links, but that a solution would be backward compatible with 802.1, including hubs, bridges, and their existing plug-and-play capabilities. This memo provides information for the Internet community.