Common Control and Measurment Plane I. Hussain Internet-Draft R. Valiveti Intended status: Informational Infinera Corp Expires: August 17, 2019 Q. Wang ZTE L. Andersson M. Chen H. Zheng Huawei February 13, 2019 GMPLS Routing and Signaling Framework for Flexible Ethernet (FlexE) draft-izh-ccamp-flexe-fwk-07 Abstract This document specifies the GMPLS control plane requirements, framework, and architecture for the FlexE technology. The document also discusses interoperation between the GMPLS control plane for FlexE and the control plane of any networking layer using the FlexE technology as a server layer. As different from earlier Ethernet data planes FlexE allows for decoupling of the Ethernet Physical layer (PHY) and Media Access Control layer (MAC) rates. Study Group 15 (SG15) of the ITU-T has endorsed the FlexE Implementation Agreement from Optical Internetworking Forum (OIF) and included it, by reference, in some of their Recommendations. Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at https://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on August 17, 2019. Hussain, et al. Expires August 17, 2019 [Page 1] Internet-Draft FlexE Extensions February 2019 Copyright Notice Copyright (c) 2019 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 (https://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. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1. Requirements Language . . . . . . . . . . . . . . . . . . 5 1.2. Updates in the version . . . . . . . . . . . . . . . . . 5 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 6 3. FlexE Reference Model . . . . . . . . . . . . . . . . . . . . 7 4. GMPLS Controlled FlexE . . . . . . . . . . . . . . . . . . . 8 4.1. Interfaces in a FlexE network . . . . . . . . . . . . . . 9 4.2. Mapping of traffic in the data plane . . . . . . . . . . 9 4.3. The GMPLS Control Plane and the FlexE identifiers . . . . 10 4.4. Operational concerns . . . . . . . . . . . . . . . . . . 11 4.5. Pre-configured vs. Control Plane established LSPs in a FlexE capable network . . . . . . . . . . . . . . . . . . 11 4.6. Signaling Channel . . . . . . . . . . . . . . . . . . . . 12 4.7. MPLS LSP over the FlexE Data Plane . . . . . . . . . . . 12 4.8. Configuring the data plane in FlexE capable nodes . . . . 14 4.8.1. Configure/Establish a FlexE Group/Link . . . . . . . 14 4.8.2. Configure/Establish a FlexE Client . . . . . . . . . 15 4.8.3. Advertise FlexE Groups and FlexE Clients . . . . . . 15 5. Framework and Architecture . . . . . . . . . . . . . . . . . 15 5.1. FlexE Framework . . . . . . . . . . . . . . . . . . . . . 16 5.2. FlexE Architecture . . . . . . . . . . . . . . . . . . . 16 5.2.1. Architecture Components . . . . . . . . . . . . . . . 16 5.2.2. FlexE Layer Model . . . . . . . . . . . . . . . . . . 16 5.2.2.1. FlexE Group structure . . . . . . . . . . . . . . 17 5.2.2.2. FlexE Client mapping . . . . . . . . . . . . . . 17 6. Control Plane . . . . . . . . . . . . . . . . . . . . . . . . 17 6.1. GMPLS Routing . . . . . . . . . . . . . . . . . . . . . . 18 6.2. GMPLS Signaling . . . . . . . . . . . . . . . . . . . . . 18 6.2.1. LSP setup with pre-configured FlexE infrastructure . 19 6.2.2. LSP setup with partially configured FlexE infrastructure . . . . . . . . . . . . . . . . . . . 20 Hussain, et al. Expires August 17, 2019 [Page 2] Internet-Draft FlexE Extensions February 2019 6.2.3. LSP setup with non-configured FlexE infrastructure . 21 6.2.4. Packet Label Switching Data Plane . . . . . . . . . . 21 7. Operations, Administration, and Maintenance (OAM) . . . . . . 23 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 23 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 23 10. Security Considerations . . . . . . . . . . . . . . . . . . . 23 11. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 23 12. References . . . . . . . . . . . . . . . . . . . . . . . . . 23 12.1. Normative References . . . . . . . . . . . . . . . . . . 23 12.2. Informative References . . . . . . . . . . . . . . . . . 24 Appendix A. Requirements . . . . . . . . . . . . . . . . . . . . 25 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 26 1. Introduction This document specifies the GMPLS control plane requirements, framework, and architecture for the FlexE technology. The FlexE control plane requirements are found in an appendix. Prior to FlexE Ethernet MAC rates were until constrained to match the rates of the Ethernet PHY(s). FlexE, specified by the OIF, allows MAC rates to be different from PHY rates. An OIF implementation agreement [OIFFLEXE1] allows for complete decoupling of the MAC and PHY rates. This has been further extended in [OIFFLEXE2]. SG15 in ITU-T has endorsed the OIF FlexE data plane and parts of [G.872], [G.709], [G.798] and [G.8021]. The Recommendations depends on or are based on the FlexE data plane. The FlexE implementation agreement includes support for: a. MAC rates which are greater than the rate of a single PHY; multiple PHYs are bonded to achieve this b. MAC rates which are less than the rate of a PHY (sub-rate) c. support for channelization within a single PHY, or over a group of bonded PHYs. The capabilities supported by the FlexE data plane are: a. Support a large rate Ethernet MAC over bonded Ethernet PHYs, e.g. supporting a 200G MAC over 2 bonded 100GBASE-R PHY(s) b. Support a sub-rate Ethernet MAC over a single Ethernet PHY, e.g. supporting a 50G MAC over a 100GBASE-R PHY Hussain, et al. Expires August 17, 2019 [Page 3] Internet-Draft FlexE Extensions February 2019 c. Support a collection of flexible Ethernet clients over a single Ethernet PHY, e.g. supporting two MACs with the rates 25Gbps, and one with rate 50G over a single 100GBASE-R PHY d. Support a sub-rate Ethernet MAC over bonded PHYs, e.g. supporting a 150G Ethernet client over 2 bonded 100GBASE-R PHY(s) e. Support a collection of Ethernet MAC clients over bonded Ethernet PHYs, e.g. supporting a 50G and 150G MAC over 2 bonded 100GBASE-R PHY(s) FlexE networks feature FlexE Ethernet interfaces, for more details see Section 4.1. From a control plane perspective, the FlexE Groups may be viewed as logical links and FlexE Clients as logical sub-interfaces (or channelized interfaces). These logical point-to-point links may be realized in at least two different ways: a. direct point-to-point links with no intervening transport network. b. direct point-to-point links across a transport network transport network. c. Ethernet PHY(s) may be transparently transported via an Optical Transport Network (OTN), as defined by ITU-T in [G.709] and [G.798]. The OTN set of client mappings has been extended to support the use cases identified in the OIF FlexE implementation agreement. This document is a framework for the network control plane signaling and routing extensions required to establish FlexE links (FlexE Groups (PHY) and FlexE Clients (MAC)). FlexE Links may interconnect customer edge devices (CE to CE), CE to provider edge devices (PE), PE to PE, or devices at the edge to devices in the core (PE to P) or devices in the core (P to P). Any pair of neighbouring L2 and L3 device that support FlexE interfaces may be interconnected P2P using a FlexE link (PHY and MAC). Further a device that terminates a FlexE link MUST be able to extract either the L2 or L3 payload and switch on the appropriate level, i.e. Ethernet, MPLS or IP. It should be noted that any type of switching is outside is out of scope for the FlexE specification. Hussain, et al. Expires August 17, 2019 [Page 4] Internet-Draft FlexE Extensions February 2019 FlexE CE devices may typically be L3 routers or other devices that use FlexE at layers 1 and 2 to provide point-to-point connectivity between each other. Thus this draft considers the cases in which the two peer FlexE devices are: o interconnecting two parts of a customer network (CE to CE). o at the edge of the customer network (CE) and the close edge of the provider network (PE to CE). o opposite edges of the FlexE capable network (PE tom PE). o at the edge of the FlexE network PE interconnected to a provider device (PE to P). o interconnecting two provider devices (P to P). This list of deployment cases will help identify the GMPLS control plane (i.e. routing and signaling) extensions that may be required to support establishment of FlexE services. 1.1. Requirements Language The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here. 1.2. Updates in the version This section will be removed before posting. 1. Following a suggestion from Daniele the FlexE Control Plane Requirements has been moved to an appendix. 2. There are still some of the comments from Daniele that might need to be addressed, but we have had a pretty large overlap in comments, so the intention is that all should be addressed. 3. The terms Ethernet Interface and Ethernet sub-Interface has been re-introduced in relation to FlexE Group and FlexE Client respectively. Hussain, et al. Expires August 17, 2019 [Page 5] Internet-Draft FlexE Extensions February 2019 4. Except for some spelling corrections Section 5 to Section 7 are virtually untouched, though it is likely that some of the changes in the earlier parts of the document will have to be reflected into those sections also. 2. Terminology a. CE (Customer Edge): the group of functions that support the termination/origination of data received from or sent to the network. Sometimes the term CE device is used. b. controller: a joint term for any entity that may set up a LSP, FlexE Group or FlexE Client, e.g. a control plane, centralized controller, YANG model or management system. c. crunch: the term crunch in the context of OTN networks and FlexE links is used when e.g. unavailable calendar slots are not transported across the OTN network, but are removed at the ingress and recreated at the egress. d. Ethernet PHY: an entity representing Physical Coding Sublayer (PCS), Physical Media Attachment (PMA), and Physical Media Dependent (PMD) layers. e. FlexE Calendar: The total capacity of a FlexE Group is represented as a collection of slots which have a granularity of 5Gbps. The calendar for a FlexE Group composed of n 100G PHYs is represented as an array of 20n slots (each representing 5Gbps of bandwidth). This calendar is partitioned into sub-calendars, with 20 slots per 100G PHY. Each FlexE Client is mapped into one or more calendar slots (based on the bandwidth the FlexE Client flow will need). f. FlexE Channelized sub-Interface, the channelized Ethernet sub- interface realized by the FlexE Client. g. FlexE Client: An Ethernet flow based on a MAC data rate that may or may not correspond to any Ethernet PHY rate. h. FlexE Group: A FlexE Group is composed of from 1 to n Ethernet PHYs. In the first version of FlexE each PHY is identified by a number in the range {1-254}. i. FlexE Interface, the Ethernet interface realized the FlexE Group j. FlexE Shim: the layer that maps or demaps the FlexE Client flows carried over a FlexE Group. Hussain, et al. Expires August 17, 2019 [Page 6] Internet-Draft FlexE Extensions February 2019 k. LMP: Link Management Protocol l. LSP: Label Switched Path m. OIF: Optical Internetworking Forum n. OTN: Optical Transport Network o. PE: Provider Edge (device) the term is used for the functions needed at the edge of a provider network or the device to which these functions are allocated. p. P: Provider (device), the term is used for the functions needed in the core of a provider network or the device to which these functions are allocated. q. SG15: ITU-T Study Group 15 (Transport, Access and Home). r. TE: Traffic Engineering s. TED: Traffic Engineering Database 3. FlexE Reference Model The figure below gives a simplified FlexE reference model. Hussain, et al. Expires August 17, 2019 [Page 7] Internet-Draft FlexE Extensions February 2019 +-----+ | P | ...........+-+-+-+............. n x PHY . n x | | m x . . crunched | | crunched . +----+ +-----+ PHYs | | PHYs +-----+ +----+ | CE +------+ PE1 +------------+ +--------------+ PE2 +----+ CE | +----+ +-----+ +-----+ +----+ . . +----+ p x PHY . . +----+ | CE +-----------------------------------------------------+ CE | +----+ . . +----+ . OTN Network . . . ............................... +----+ q x PHY +----+ | CE +-----------------------------------------------------+ CE | +----+ +----+ Legend: m, n, p and q indicate how many PHYs there are in a FlexE Group Figure 1: FlexE Reference Model The services offered by Flexible Ethernet are essentially the same as for traditional Ethernet, connection less Ethernet transport. In essence the FlexE interfaces and links may be viewed as any other Ethernet interfaces or links. However, it is possible to capture additional TE information in the Traffic Engineering Data Base showing unique characteristics of FlexE channelized interfaces and links. This makes it possible for the control plane to strategically use FlexE networks to support advanced TE. 4. GMPLS Controlled FlexE The high level goals for using a GMPLS control plane for FlexE can be summarized as: o Set up a FlexE Group o Set up a FlexE Client o Advertise the TE information of FlexE Groups and FlexE Clients Hussain, et al. Expires August 17, 2019 [Page 8] Internet-Draft FlexE Extensions February 2019 o Set up of a higher layer LSPs that require to be (or would have significant benefits to) be run over a FlexE infrastructure. o Decoupling PHY and MAC bandwidth opens up some interesting features for networks that features FlexE links. By establishing several FlexE Clients with bandwidth that are part of the bandwidth of the FlexE Group, it is possible to create channels between to nodes. o By controlling the mapping a user packets (or frames) to these channels it is possible to create bandwidth that are dedicated for special purposes, and that can't be infringed on by packets (or frames) that does not satisfy this mapping. 4.1. Interfaces in a FlexE network FlexE Ethernet interfaces are realized by the means of a basic building block. The same building block is used for a single PHY and when the PHY's are bonded. The building block consists of two FlexE Shim functions (see Section 5.2.2.2) and a logical point to point link. The FlexE Shim functions are located at each end of the logical point to point link. This link carries the Ethernet PHY signals between the two FlexE Shim Functions. 4.2. Mapping of traffic in the data plane An example of which data plane mappings takes palace when an upper layer, e.g. IP or MPLS, send packets over a FlexE interfaces is shown in Figure 2. Hussain, et al. Expires August 17, 2019 [Page 9] Internet-Draft FlexE Extensions February 2019 IP packet IP Layer || \/ MPLS encapsulation MPLS || \/ FlexE Client ID FlexE || \/ calendar mapping FlexE || \/ FlexE Group FlexE Figure 2: Traffic Mapping In the mapping steps indicated in Figure 2 only one step in the mapping is visible by each layer. o the MPLS layer knows from the IP address, which MPLS label stack to encapsulate the IP packet in o the MPLS layer also know which MPLS label(s) that maps to which FlexE Client o the FlexE layer also knows from the FlexE Client Identifier, which calendar slots the packet will be transferred over o the FlexE layer knows which FlexE Group a certain set of calendar slots belongs too 4.3. The GMPLS Control Plane and the FlexE identifiers This section lists some of the procedures and actions on FlexE Interface Identifiers that a GMPLS Control plane need to perform. Also, a centralized controller, YANG model or a management system that are used to establish interfaces and links need to perform the same actions. The FlexE Group Identifier and the FlexE Client Identifier, included in the overhead of each frame sent over a FlexE Interface or sub- Interface, indicates a particular Group or Client. When the Control Plane, a centralized controller, a YANG model or a management system sets up a FlexE Interface at least the bandwidth Hussain, et al. Expires August 17, 2019 [Page 10] Internet-Draft FlexE Extensions February 2019 has to in included in the setup message. The FlexE system return the FlexE Group Identifier in the response message. When a channelized sub-interface is set up, the party the initiates the setup includes the Interface (FlexE Group) Identifier) over which the sub-Interface will be established, and the bandwidth requested for the sub-interface. The FlexE system returns the FlexE Client Identifier. The identifiers received by the party that initiate a setup of an FlexE Interfaces are used, by a controller, to set up FlexE sub- interfaces. The identifiers received by the party that initiate a setup of an FlexE sub-Interfaces are used, e.g. to map an MPLS label to the correct FlexE sub-interfaces. 4.4. Operational concerns When operating a links in a FlexE network it is likely that an operator would like to split the FlexE Interface in sub-Interfaces used for best effort traffic and sub-Interfaces for dedicated for special purposes. An example would be when there is a 100 Gbit/s FlexE are split in to five 10 Gbit/s sub-interfaces and one 50 Gbit/s sub-interface. The 50 Gbit/s sub-interface could be used best effort traffic, the five 10 Gbit/s could be used for dedicated traffic. In such cases it is conceivable that packets/frames that have a matching key will be put on a specific sub-Interface, while traffic that do not have a matching key will be put on the best effort sub- interface. 4.5. Pre-configured vs. Control Plane established LSPs in a FlexE capable network The FlexE infrastructure may be established in three different ways o The FlexE Groups and FlexE Client may be pre-configured o Only the FlexE Groups may be pre-configured, while the setup of the FlexE Client is triggered by the request to setup a MPLS LSP. o The setup of both FlexE Group and FlexE Client may be triggered by the request to setup an MPLS LSP. In the case the FlexE Groups and FlexE Clients are preconfigured the FlexE capable nodes need to have the ability to announce the preconfigured FlexE Client and/or FlexE Groups as if they were LSPs. Hussain, et al. Expires August 17, 2019 [Page 11] Internet-Draft FlexE Extensions February 2019 4.6. Signaling Channel In the type of equipment for which FlexE was first specified an out of band signaling channel is not commonly available. If that is the case, and the GMPLS FlexE control plane will be used, the FlexE Group will have to setup by e.g. a management system and a FlexE Client on that FlexE Group (also configured) will have to allocated as a signaling channel. Further details of the setup of the FlexE Groups, FlexE Clients and MPLS LSPs over a FlexE infrastructure will be found in Section 6.2. 4.7. MPLS LSP over the FlexE Data Plane FlexE is a true link layer technology, i.e. it is not switched, this means that the FlexE Groups and FlexE Clients are terminated on the next-hop node, and that the switching needs to take place on a higher layer. The FlexE technology can be used to establish link layer connectivity with high and deterministic bandwidth. However, there is no way described in the FlexE specification to, in a deterministic way, allocate certain traffic to a specific FlexE Client. Control of the FlexE link layer by a GMPLS control plane can achieve this. A GMPLS controlled FlexE capable node may be thought of using the traditional model of a node with a separation between control and data plane. Hussain, et al. Expires August 17, 2019 [Page 12] Internet-Draft FlexE Extensions February 2019 +------------------+ | +------------+ | | | GMPLS | | | | Control | | | | Plane | | | +------------+ | | ^ | | | | | v | | +------------+ | | | FlexE | | | | Data | | ^ | | Plane | | | +------------+ | +------------------+ Figure 3: GMPLS controlled FlexE Node The GMPLS control plane will speak extended standard GMPLS protocols with its neighbours and peers. Node A Node B Node Z +--CP +-|-----------+ |------------------+ ~ +---------+ | | | | | | | | | +------+ | | +--------------+ | | +-----+ | LSP | +->| v | | | | ....x..... | | | | ^ | | | | | . | | | | . . | | | | . | | | | +--.---+ | | +--.--------.--+ | | +--.--+ | FlexE | +->| o | | | | o | | o | | | | o | | Client | | | o | | | | o | | o | | | | o | | | | +--o---| | | +--o--+ +--o--+ | | +--o--| | FlexE | +->| U | | | | U | | U | | | | U | | Group | | U | | | | U | | U | | | | U | | | +--U---| | | +--U--+ +--U--+ | | +--U--+ | |-------U-----+ +----U--------U----+ +----U----+ U U U U UUUUUUUUUUUUUUUUUUUUU UUUUUUU ~ UUUUUUUU Legend ... = LSP ooo = FlexE Client UUU = FlexE Group Figure 4: GMPLS controlled network with FlexE infrastructure Hussain, et al. Expires August 17, 2019 [Page 13] Internet-Draft FlexE Extensions February 2019 Figure 4 describes how an MPLS LSP is mapped over a FlexE Client and FlexE Group. 4.8. Configuring the data plane in FlexE capable nodes In Figure 4 we show an LSP, a FlexE Client and a FlexE Group, the LSP is there because while the FlexE Channel and Group are not switched, switching in our example takes place on the LSP level. This section will discuss establishment of FlexE Clients and Groups, and mapping of the LSP onto a FlexE Client. The establishment of a LSP over a FlexE system is very similar to how this is done in any other system. Building on information gathered through the routing system and using the GMPLS signaling to establish the LSP. 4.8.1. Configure/Establish a FlexE Group/Link Consider the setup of a FlexE Group between node A and B, corresponding to the row of U's from node A to B in Figure 4. The FlexE Group is considered to consist of n PHYs, but does not have any FlexE Clients defined from start. When this is done by the GMPLS control plane, two conditions need to be fulfilled (1) there need to be a data channel defined between node A and B; and (2) a FlexE capable IGP-TE protocol needs to be running in the network. Node A will send an RSVP-TE message to node be with the information describing the FlexE Group to be setup. This information might be thought of as the "FlexE Group Label" (or part of the FlexE label). It will contain at least the following information: o A FlexE Group Identifier (FGid). o The number of active FlexE Channels (numFC), where 0 indicates that zero clients are active. o Number of PHYs that the FlexE Group is composed of, for each PHY * PHY identifier * PHY bandwidth * slot granularity/number of slots * available and unavailable slots Hussain, et al. Expires August 17, 2019 [Page 14] Internet-Draft FlexE Extensions February 2019 When node B receives the RSVP-TE message it checks that it can setup the requested FlexE Group. If the check turns positive, node send an acknowledgment to node A and the FlexE Group is setup. A more detailed description of how to setup a FlexE Group, will be included in the draft dealing with signaling in detail. 4.8.2. Configure/Establish a FlexE Client Consider the situation where a FlexE Group is already established (as described in Section 4.8.1) and an m G FlexE Client is needed. Similar to the establishment of the FlexE Group, node A will send a RSV-TE message to node B. This RSVP-TE message include at least the following information: o FlexE Group Identifier o FlexE Client Identifier o from which PHYs the slots will allocated, i.e. slots might come from more than one PHY. o Information per PHY * PHY bandwidth * slot granularity * available/unavailable slots * allocated slots A more detailed description of how to setup a FlexE Channel, will be included in the draft dealing with signaling in detail. 4.8.3. Advertise FlexE Groups and FlexE Clients Once the FlexE Group and FlexE Clients are configured they can be advertised into the routing system as normal routing adjacencies, including the FlexE specific TE information. 5. Framework and Architecture This section discusses FlexE framework and architecture. Framework is taken to mean how FlexE interoperates with other parts of the data communication system. Architecture is taken to mean how functional groups and elements within FlexE work together to deliver the Hussain, et al. Expires August 17, 2019 [Page 15] Internet-Draft FlexE Extensions February 2019 expected FlexE services. Framework is taken to mean how FlexE interacts with it environment. 5.1. FlexE Framework The service offered by Flexible Ethernet is a transport service very similar (or even identical) to the service offered by Ethernet. There are two major additions supported by FlexE: o FlexE is intended to support high bandwidth and FlexE can offer granular bandwidth from 5Gbits/s and a bandwidth as high as the FlexE Group allows. o As FlexE Groups and clients are setup as a configuration activity, by a centralized controller or by a GMPLS control plane the service is connection oriented. 5.2. FlexE Architecture 5.2.1. Architecture Components This section discusses the different parts of FlexE signaling and routing and how these parts interoperate. The FlexE routing mechanism is used to provide resource available information for setup of higher layer LSPs, like Ethernet PHYs' information, partial-rate support information. Based on the resource available information advertised by routing protocol, an end-to-end FlexE connection is computed, and then the signaling protocol is used to set up the end-to-end connection. FlexE signaling mechanism is used to setup LSPs. MPLS forwarding over a FlexE infrastructure is different from forwarding over other infrastructures. When MPLS runs over a FlexE infrastructure it is possible that there are more than FlexE Client that meet the next-hop requirements, often it is possible to use any suitable FlexE Clientfor a hop between two nodes. If the mapping between a MPLS encapsulated packet and the FlexE Client, this mapping need to be explicit when the LSP is set up, and the MPLS label will be used to find the correct FlexE Client. 5.2.2. FlexE Layer Model The FLexE layer model is similar Ethernet model, the Ethernet PHY layer corresponds to the "FlexE Group", and the MAC layer corresponds to the "FlexE Client". Hussain, et al. Expires August 17, 2019 [Page 16] Internet-Draft FlexE Extensions February 2019 As different from earlier Ethernet the combination of Flexe Group and Client allows for a huge freedom when it comes to define the bandwidth of an Ethernet connectivity. 5.2.2.1. FlexE Group structure The FlexE Group might be supported by virtually any transport network, including the Ethernet PHY. While the Ethernet PHY offers a fixed bandwidth the FlexE Group has been structured into 5 Gbit/s slots. This means that the FlexE Group can support FlexE Clients of a variety of bandwidths. The first version is defined for 20 slots of 5 Git/s over a 100 Gbit/ s PHY. The 100 Gbit/s PHYs can be bonded to give higher bandwidth. 5.2.2.2. FlexE Client mapping A FlexE Client is an Ethernet flow based on a MAC data rate that may or may not correspond to any Ethernet PHY rate. The FlexE Shim is the layer that maps or demaps the FlexE Client flows carried over a FlexE Group. As defined in [OIFFLEXE1], MAC rates of 10, 40, and any multiple of 25 Gbit/s are supported. This means that if there is a 100 Gbit/s FlexE Group between A and B, a FlexE Client of 10, 25, 40, 50, 75 and 100 Gbit/s can be created. However, by bonding, for example 5 PHYs of 100 Git/s to a single FlexE Group, FlexE Clients of 500 Gbit/s can be supported. 6. Control Plane This section discusses the procedures and extensions needed to the GMPLS Control Plane to establish FlexE LSPs. There are several ways to establish FlexE Groups, allocate slots for FlexE Clients, and setup higher layer LSPs. A configuration tool, a centralized controller or the GMPLS control plane can all be used. To create the FlexE GMPLS control plane Groups, FlexE Clients and higher layer LSPs, extensions to the following protocols may be needed: o "RSVP-TE: Extensions to RSVP for LSP Tunnels" (RSVP-TE) [RFC3209] o "Link Management Protocol" (LMP) [RFC4204] o "Path Computation Element (PCE) Communication Protocol" (PCEP) [RFC5440] Hussain, et al. Expires August 17, 2019 [Page 17] Internet-Draft FlexE Extensions February 2019 o IS-IS Extensions for Traffic Engineering (ISIS-TE) [RFC5305] o "OSPF Extensions in Support of Generalized Multi-Protocol Label Switching (GMPLS)" (OSPF-TE) [RFC4203] o "North-Bound Distribution of Link-State and Traffic Engineering (TE) Information Using BGP" (BGP-LS) [RFC7752] A FlexE control plane YANG model will also be needed. Section 6.2 and Section 6.1 discusses the role of the GMPLS control plane when primarily setting up LSPs. When discussing the signaling and routing procedures we assume that the FlexE Group has been established prior to executing the procedures needed to establish an LSP. Technically it is possible to establish FlexE Group, allocate FlexE Client slots and LSP with a single exchange of GMPLS signaling messages. 6.1. GMPLS Routing To establish an LSP the Traffic Engineering (TE) information is the most critical information, e.g. resource utilization on interfaces and link, including the availability of slots on the FlexE Groups. The GPMPLS routing protocols needs to be extended to handle this information. The Traffic Engineering Database (TED) will keep an updated version of this information. The FlexE capable nodes will be identified by IP-addresses, and the routing and traffic engineering information will be flooded to all nodes within the routing domain using TCP/IP. When an LSP over the FlexE infrastructure is about to be setup, e.g. R1 - R4 - R5 in Figure 5 the information in the TED is used verify that resources are available. When it is conformed that the LSP is established the TED is updated, marking the resources used for the new LSP as used. Similarly, when a LSP is taken down the resources are marked as free. 6.2. GMPLS Signaling As described in Section 4 the state of the FlexE infrastructure may effect the actions needed to setup an LSP in a FlexE capable network. The FlexE infrastructure maybe be: 1. fully pre-configured Hussain, et al. Expires August 17, 2019 [Page 18] Internet-Draft FlexE Extensions February 2019 2. partially pre-configured, i.e. the FlexE Group may be pre- configured, but not the FlexE Clients 3. not pre-configured, i.e. the setup of FlexE Group and FlexE Client will be triggered because of the request to setup an LSP. Figure 5 will be used to illustrate the different cases. +----+ | R1 +---------------------+ +----+ | | +----+ +--+--+ +----+ | R2 +------------------+ R4 +-------------------------+ R5 | +----+ +--+--+ +----+ | +----+ | | R3 +---------------------+ PHY R1 to R4 100 Gbit(s +----+ PHY R2 to R4 100 Gbit(s PHY R3 to R4 100 Gbit(s PHY R4 to R5 200 Gbit(s Figure 5: FlexE LSP Example The text in Section 6.2 is not a specification of the GMPLS signaling extensions for FlexE capable network, it is a description to illustrate the expected features of such a protocol. Nor do we discuss failure scenarios. 6.2.1. LSP setup with pre-configured FlexE infrastructure In this first example, referencing Figure 5, one 100 Gbit/s FlexE Group is configured between R1 and R4, between R2 and R4, and between R3 and R4. Between R4 and R5 there is a 200 Gbit/s FlexE Group. Over each 100 Gbit/s FlexE Group there are four 5 Gbit/s, two 20 Gbit/s and one 40 Gbit/s FlexE Clients configured. Over the 200 Git/ s FlexE Group there are eight 5 Gbit/s, four 20 Gbit/s and two 40 Gbit/s FlexE Clients configured. One of the 5 Gbit/s FlexE Clients on each FlexE Groups are used as signaling channel. Hussain, et al. Expires August 17, 2019 [Page 19] Internet-Draft FlexE Extensions February 2019 To establish the for example a 200 Mbit/s MPLS LSP the normal GMPLS request/response procedures are followed. R1 sends the request to R4, R4 allocate resources on one of the FlexE Clients, forward the request to R5. R5 responds to R4 indicating the label and the FlexE Client the traffic should be sent over, R4 does the same for R1. The only difference between the standard signaling and what happens here is that there the assigned label will be used to find the right FlexE Client. 6.2.2. LSP setup with partially configured FlexE infrastructure In the second example, also referencing Figure 5, the FlexE Groups are setup in the same way as in the first example, however only one 5 Gbit/s FlexE Client per FlexE Group are established by configuration. This FlexE Client will be used for signaling. When preparing to send the request that a 5 Gbit/s MPLS LSP shall be set up R1 discovers that there are no feasible FlexE Client between R1 aand R4. R1 therefore sends the request to establish such a FlexE Client, when receiving the request R4 allocates resources for the FlexE Client on the FlexE Group. There may be different strategies for allocating the bandwidth for this FlexE Client. Such strategies are out of scope for this document. R1 then sends the information about the FlexE Client to R1, and both ends establish the FlexE Client. When the FlexE Client between R1 and R4 is established, R1 proceeds to send the request for an MPLS LSP to R4. R4 will discover that a feasible FlexE Client is missing between R4 and R5. The same procedure s for setting up the FlexE Client between R1 and R4 is repeated for R4 and R5. When there is a feasible FlexE Client available the signaling to set up the MPLS LSP continues as normal. The label allocated for the MPLS LSP will be used to find the correct FlexE Client. When a FlexE Clients is set up in this way they can be announced into the routing system in two different ways. First, they can be made generally available, i.e. it will be free to use for anyone that want to set up LSPs over the FlexE Group between R1 and R4 and between R4 and R5. Second, the use of the FlexE Clients may be restricted to the application that initially did set up the FlexE Client. Hussain, et al. Expires August 17, 2019 [Page 20] Internet-Draft FlexE Extensions February 2019 6.2.3. LSP setup with non-configured FlexE infrastructure This example also refers to Figure 5 as different from the earlier example no FlexE Group or FlexE Client configuration is done prior to the first request for an MPLS LSP over the FlexE infrastructure. To make the set up of LSPs in a FlexE network where no FlexE Groups or FlexE Clients have been configured two conditions need to be fulfilled. First an out of band signaling channel must be available. Second the FlexE Capabilities must be announced in to the IGP and/or centralized controller. If these two conditions are fulfilled, the set up of an MPLS LSP progress pretty much as in the partially configured network. The difference is that the set up of both the FlexE Group and FlexE Client are triggered by the request to set up an MPLS LSP. As in the partially configured case FlexE Clients can be announced into the routing system in two different modes, either they are generally available. It or they are reserved for the applications that first established them. 6.2.4. Packet Label Switching Data Plane This section discusses how the FlexE LSP data plane works. In general it can be said that the interface offered by the FlexE Shim and the FlexE Client is equivalent to the interface offered by the Ethernet MAC. Figure 6 below illustrates the FlexE packet switching data plane procedures. Hussain, et al. Expires August 17, 2019 [Page 21] Internet-Draft FlexE Extensions February 2019 R1 R3 R4 ............. ...................... ........... . +-------+ . . +----------------+ . . +-----+ . . | LSP | . . | LSP \ / LSP | . . | LSP | . . | a | . . | a \/ b | . . | b | . . +-------+ . . +----------------+ . . +-----+ . . | ETH | . . | ETH | | ETH | . . | ETH | . . | i/f | . . | i/f | | i/f | . . | i/f | . . +-------+ . . +-----+ +-----+ . . +-----+ . . | FlexE | . . |FlexE| |FlexE| . . |FlexE| . . | trsp | . . |trsp | |trsp | . . |trsp | . . +---+---+ . . +--+--+ +--+--+ . . +--+--+ . ......|...... .....^..........|..... .....^..... | | | | +--------------------+ +--------------------+ Figure 6: LSP over FlexE Data Plane The data plane processes packets like this: o The LSP encapsulating and forwarding function in node R1 receives a packet that needs to be encapsulated as an MPLS packet with the label "a". The label "a" is used to figure out which FlexE emulated Ethernet interfaces the label encapsulated packet need to be forwarded over. o The Ethernet interfaces, by means of FlexE transport, forwards the packet to node R3. Node R3 swaps the label "a" to label "b" and uses "b" to decide over which interface to send the packet. o Node R3 forwards the packet to node R, which terminates the LSP. Sending MPLS encapsulated packets over a FlexE Client is similar to send them over an Ethernet 802.1 interface. The critical differences are: o FlexE channelized sub-interfaces guarantee a deterministic bandwidth for an LSP. o When a application that originally establish a FlexE Client reserve it for use by that application only, it is possible to create uninfringeable bandwidth end-to-end for an MPLS LSP. o FlexE infrastructure allows for creating very large end to end bandwidth Hussain, et al. Expires August 17, 2019 [Page 22] Internet-Draft FlexE Extensions February 2019 7. Operations, Administration, and Maintenance (OAM) To be added in a later version. 8. Acknowledgements 9. IANA Considerations This memo includes no request to IANA. Note to the RFC Editor: This section should be removed before publishing. 10. Security Considerations To be added in a later version. 11. Contributors Khuzema Pithewan, Infinera Corp, kpithewan@infinera.com Fatai Zhang, Huawei, zhangfatai@huawei.com Jie Dong, Huawei, jie.dong@huawei.com Zongpeng Du, Huawei, duzongpeng@huawei.com Xian Zhang, Huawei, zhang.xian@huawei.com James Huang, Huawei, james.huang@huawei.com Qiwen Zhong, Huawei, zhongqiwen@huawei.com Yongqing Zhu China Telecom zhuyq@gsta.com Huanan Chen China Telecom chenhuanan@gsta.com 12. References 12.1. Normative References [G.709] ITU, "Optical Transport Network Interfaces (http://www.itu.int/rec/T-REC-G.709-201606-P/en)", July 2016. Hussain, et al. Expires August 17, 2019 [Page 23] Internet-Draft FlexE Extensions February 2019 [G.798] ITU, "Characteristics of optical transport network hierarchy equipment functional blocks (http://www.itu.int/rec/T-REC-G.798-201212-I/en)", February 2014. [G.8021] ITU, "Characteristics of Ethernet transport network equipment functional blocks", November 2016. [G.872] ITU, "Architecture of optical transport networks", January 2017. [OIFFLEXE1] OIF, "FLex Ethernet Implementation Agreement Version 1.0 (OIF-FLEXE-01.0)", March 2016. [OIFFLEXE2] OIF, "FLex Ethernet Implementation Agreement Version 2.0 (OIF-FLEXE-02.0)", June 2018. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . 12.2. Informative References [RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V., and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP Tunnels", RFC 3209, DOI 10.17487/RFC3209, December 2001, . [RFC4203] Kompella, K., Ed. and Y. Rekhter, Ed., "OSPF Extensions in Support of Generalized Multi-Protocol Label Switching (GMPLS)", RFC 4203, DOI 10.17487/RFC4203, October 2005, . [RFC4204] Lang, J., Ed., "Link Management Protocol (LMP)", RFC 4204, DOI 10.17487/RFC4204, October 2005, . [RFC5305] Li, T. and H. Smit, "IS-IS Extensions for Traffic Engineering", RFC 5305, DOI 10.17487/RFC5305, October 2008, . Hussain, et al. Expires August 17, 2019 [Page 24] Internet-Draft FlexE Extensions February 2019 [RFC5440] Vasseur, JP., Ed. and JL. Le Roux, Ed., "Path Computation Element (PCE) Communication Protocol (PCEP)", RFC 5440, DOI 10.17487/RFC5440, March 2009, . [RFC7752] Gredler, H., Ed., Medved, J., Previdi, S., Farrel, A., and S. Ray, "North-Bound Distribution of Link-State and Traffic Engineering (TE) Information Using BGP", RFC 7752, DOI 10.17487/RFC7752, March 2016, . Appendix A. Requirements This section summarizes the signaling and routing requirements for a FlexE control plane, with respect to establishing FlexE Groups, FlexE Clients and MPLS LSPs that require support from an FlexE infrastructure. Req-1 The FlexE control plane SHALL support the creation of FlexE Groups. * A FlexE Groups consist one or more 100GE Ethernet PHY(s). In the first version of FlexE the number of PHYs are in the range of 1 to 254. * This requirement can be met by several methods, e.g. routing and signaling protocols, a centralized controller or a management system. Any such method need to have network access to the FlexE shims at each of the Ethernet PHY(s) termination points. Req-2 The FlexE control plane SHALL have the ability to delete a FlexE Group. Req-3 The FlexE control plane SHALL have the ability to initiate an administratively lock or unlock of a FlexE Group. * This ability is needed e.g. for executing the next requirement. Req-4 When a FlexE Group has been administratively looked is SHALL be possible to add PHYs to an operational FlexE Group. Req-5 When a FlexE Group has been administratively looked is SHALL be possible to remove PHYs from an operational FlexE Group. Hussain, et al. Expires August 17, 2019 [Page 25] Internet-Draft FlexE Extensions February 2019 Req-6 The FlexE control plane SHALL support the ability to collect, advertise and discover information about FlexE capable nodes, including the TE information the FlexE Groups and FlexE Clients the nodes support. Note: In essence correct, but something is backward. Need to think. Req-7 The FlexE control plane SHALL allow the addition (or removal) of one or more FlexE clients to a FlexE Group. The addition (or removal) of a FlexE Client flow SHALL NOT affect the services of the other FlexE Client signals. Req-8 The FlexE control plane SHALL, though this MAY not be possible in all network scenarios, support FlexE Client flow resizing without affecting any existing FlexE Clients within the same FlexE Group. Req-9 The FlexE control plane SHALL support establishment of MPLS LSPs that requires the support of a FlexE infrastructure. Authors' Addresses Iftekhar Hussain Infinera Corp 169 Java Drive Sunnyvale, CA 94089 USA Email: IHussain@infinera.com Radha Valiveti Infinera Corp 169 Java Drive Sunnyvale, CA 94089 USA Email: rvaliveti@infinera.com Qilei Wang ZTE Nanjing CN Email: wang.qilei@zte.com.cn Hussain, et al. Expires August 17, 2019 [Page 26] Internet-Draft FlexE Extensions February 2019 Loa Andersson Huawei Stockholm Sweden Email: loa@pi.nu Mach Chen Huawei CN Email: mach.chen@huawei.com Haomian Zheng Huawei CN Email: zhenghaomian@huawei.com Hussain, et al. Expires August 17, 2019 [Page 27]