Change:
compatible with and useful to, DetNet networks.  All these functions have to identify flows those require TSN treatment. <del> As is the case for DetNet, a Layer 2 network node such as a bridge may need to identify the specific DetNet flow to which a packet belongs in order to provide the TSN/DetNet QoS for that packet.  It also may need a CoS marking, such as the priority field of an IEEE Std 802.1Q VLAN tag, to give the packet proper service. </del> <ins> TSN capabilities of the TSN sub-network are made available for MPLS (DetNet) flows via the protocol interworking function defined in IEEE8021CB.  For example, applied on the TSN edge port it can convert an ingress unicast MPLS (DetNet) flow to use a specific Layer-2 multicast destination MAC address and a VLAN, in order to direct the packet through a specific path inside the bridged network.  A similar interworking function pair at the other end of the TSN sub-network would restore the packet to its original Layer-2 destination MAC address and VLAN. Placement of TSN functions depends on the TSN capabilities of nodes. MPLS (DetNet) Nodes may or may not support TSN functions.  For a given TSN Stream (i.e., DetNet flow) an MPLS (DetNet) node is treated as a Talker or a Listener inside the TSN sub-network. </ins> <del> The challange for MPLS DeNet flows is that the protocol interworking function defined in IEEE8021CB works only for IP flows.  The aim of the protocol interworking function is to convert an ingress flow to use a specific multicast destination MAC address and VLAN, for example to direct the packets through a specific path inside the bridged network.  A similar interworking pair at the other end of the TSN sub-network would restore the packet to its original destination MAC address and VLAN. As protocol interworking function defined in IEEE8021CB does not work for MPLS labeled flows, the DetNet MPLS nodes MUST ensure proper TSN sub-network specific Ethernet encapsulation of the DetNet MPLS packets.  For a given TSN Stream (i.e., DetNet flow) an MPLS (DetNet) node MUST behave as a TSN-aware Talker or a Listener inside the TSN sub-network. 6.1. TSN capable MPLS (DetNet) nodes are TSN-aware Talker/Listener as shown in fig_mpls_with_tsn.  MPLS (DetNet) node MUST provide the TSN sub-network specific Ethernet encapsulation over the link(s) towards the sub-network.  An TSN-aware MPLS (DetNet) node MUST support the following TSN components: </del> <ins> 4.1. </ins> <del> For recognizing flows: </del> <ins> Mapping of a DetNet MPLS flow to a TSN Stream is provided via the combination of a passive and an active stream identification function that operate at the frame level.  The passive stream identification function is used to catch the MPLS label(s) of a DetNet MPLS flow and the active stream identification function is used to modify the Ethernet header according to the ID of the mapped TSN Stream. </ins> <del> Stream Identification (MPLS-flow-aware) </del> <ins> IEEEP8021CBdb defines a Mask-and-Match Stream identification function that can be used as a passive function for MPLS DetNet flows. </ins> <del> For FRER used inside the TSN domain, additonaly: </del> <ins> IEEE8021CB defines an Active Destination MAC and VLAN Stream identification function, what can replace some Ethernet header fields namely (1) the destination MAC-address, (2) the VLAN-ID and (3) priority parameters with alternate values.  Replacement is provided for the frame passed down the stack from the upper layers or up the stack from the lower layers. </ins> <del> Sequencing function (MPLS-flow-aware) </del> <ins> Active Destination MAC and VLAN Stream identification can be used within a Talker to set flow identity or a Listener to recover the original addressing information.  It can be used also in a TSN bridge that is providing translation as a proxy service for an End System. </ins> <del> Sequence encode/decode function </del> <ins> 4.2. </ins> <del> For FRER when the node is a TSN replication or elimination point, additionally: </del> <ins> This section covers required behavior of a TSN-aware MPLS (DetNet) node using a TSN sub-network. </ins> <del> Stream splitting function </del> <ins> From the TSN sub-network perspective MPLS (DetNet) nodes are treated as Talker or Listener, that may be (1) TSN-unaware or (2) TSN-aware. </ins> <del> Individual recovery function </del> <ins> In cases of TSN-unaware MPLS DetNet nodes the TSN relay nodes within the TSN sub-network must modify the Ethernet encapsulation of the DetNet MPLS flow (e.g., MAC translation, VLAN-ID setting, Sequence number addition, etc.) to allow proper TSN specific handling inside the sub-network.  There are no requirements defined for TSN-unaware MPLS DetNet nodes in this document. </ins> <del> [Editor's note: Should we added here requirements regarding IEEE 802.1Q C-VLAN component?] </del> <ins> MPLS (DetNet) nodes being TSN-aware can be treated as a combination of a TSN-unaware Talker/Listener and a TSN-Relay, as shown in fig_mpls_with_tsn.  In such cases the MPLS (DetNet) node must provide the TSN sub-network specific Ethernet encapsulation over the link(s) towards the sub-network. </ins> <del> The Stream Identification and The Sequencing functions are slightly modified for frames passed down the protocol stack from the upper layers. </del> <ins> A TSN-aware MPLS (DetNet) node impementations MUST support the Stream Identification TSN component for recognizing flows. </ins> <del> Stream Identification MUST pair MPLS flows and TSN Streams and encode that in data plane formats as well.  The packet's stream_handle subparameter (see IEEE8021CB) inside the Talker/Listener is defined based on the Flow-ID used in the upper DetNet MPLS layer.  Stream Identification function MUST encode Ethernet header fields namely (1) the destination MAC-address, (2) the VLAN-ID and (3) priority parameters with TSN sub-network specific values.  Encoding is provided for the frame passed down the stack from the upper layers. </del> <ins> A Stream identification component MUST be able to instantiate the following functions (1) Active Destination MAC and VLAN Stream identification function, (2) Mask-and-Match Stream identification function and (3) the related managed objects in Clause 9 of IEEE8021CB and IEEEP8021CBdb. </ins> <del> The sequence generation function resides in the Sequencing function. It generates a sequence_number subparameter for each packet of a Stream passed down to the lower layers.  Sequencing function MUST copy sequence information from the MPLS d-CW of the packet to the sequence_number subparameter for the frame passed down the stack from the upper layers. </del> <ins> A TSN-aware MPLS (DetNet) node implementations MUST support the Sequencing function and the Sequence encode/decode function as defined in IEEE8021CB if FRER is used inside the TSN sub-network. </ins> The Sequence encode/decode function MUST support the Redundancy tag (R-TAG) format as per Clause 7.8 of IEEE8021CB. <del> 6.2. </del> <ins> A TSN-aware MPLS (DetNet) node implementations MUST support the Stream splitting function and the Individual recovery function as defined in IEEE8021CB when the node is a replication or elimination point for FRER. 4.3. </ins> TSN Streams supporting DetNet flows may use Frame Replication and <del> Elimination for Redundancy (FRER) [802.1CB] based on the loss service requirements of the TSN Stream, which is derived from the DetNet service requirements of the DetNet mapped flow.  The specific operation of FRER is not modified by the use of DetNet and follows IEEE8021CB. </del> <ins> Elimination for Redundancy (FRER) as defined in IEEE8021CB based on the loss service requirements of the TSN Stream, which is derived from the DetNet service requirements of the DetNet mapped flow.  The specific operation of FRER is not modified by the use of DetNet and follows IEEE8021CB. </ins> FRER function and the provided service recovery is available only <del> within the TSN sub-network however as the Stream-ID and the TSN sequence number are paired with the MPLS flow parameters they can be combined with PREOF functions. 6.3. [Editor's note: This section is TBD - covers required behavior of a TSN-aware DetNet node using a TSN underlay.] </del> <ins> within the TSN sub-network as the TSN Stream-ID and the TSN sequence number are not valid outside the sub-network.  An MPLS (DetNet) node represents a L3 border and as such it terminates all related information elements encoded in the L2 frames. As the Stream-ID and the TSN sequence number are paired with the similar MPLS flow parameters, FRER can be combined with PREOF functions.  Such service protection interworking scenarios may require to move sequence number fields among TSN (L2) and PW (MPLS) encapsulations and they are left for further study. 4.4. Implementations of this document SHALL use management and control information to map a DetNet flow to a TSN Stream.  N:1 mapping (aggregating DetNet flows in a single TSN Stream) SHALL be supported. The management or control function that provisions flow mapping SHALL ensure that adequate resources are allocated and configured to provide proper service requirements of the mapped flows. </ins> <del> 6.4. [Editor's NOTE: review and simplify this section.  May overlap with previous sections.] The Time-Sensitive Networking (TSN) Task Group of the IEEE 802.1 Working Group have defined (and are defining) a number of amendments to IEEE8021Q that provide zero congestion loss and bounded latency in bridged networks.  IEEE8021CB defines packet replication and elimination functions that should prove both compatible with and useful to, DetNet networks. As is the case for DetNet, a Layer 2 network node such as a bridge may need to identify the specific DetNet flow to which a packet belongs in order to provide the TSN/DetNet QoS for that packet.  It also will likely need a CoS marking, such as the priority field of an IEEE Std 802.1Q VLAN tag, to give the packet proper service. Although the flow identification methods described in IEEE8021CB are flexible, and in fact, include IP 5-tuple identification methods, the baseline TSN standards assume that every Ethernet frame belonging to a TSN stream (i.e.  DetNet flow) carries a multicast destination MAC address that is unique to that flow within the bridged network over which it is carried.  Furthermore, IEEE8021CB describes three methods by which a packet sequence number can be encoded in an Ethernet frame. Ensuring that the proper Ethernet VLAN tag priority and destination MAC address are used on a DetNet/TSN packet may require further clarification of the customary L2/L3 transformations carried out by routers and edge label switches.  Edge nodes may also have to move sequence number fields among Layer 2, PW, and IP encapsulations. </del> <ins> 5. </ins> <del> 7. </del> <ins> [Editor's note: This section covers management/control plane related implications of creation, mapping, removal of TSN Stream IDs, their related parameters and, when needed, the configuration of FRER.] DetNet flow and TSN Stream mapping related information are required only for TSN-aware MPLS (DetNet) nodes.  From the Data Plane perspective there is no practical difference based on the origin of flow mapping related information (management plane or control plane). TSN-aware MPLS DetNet nodes are member of both the DetNet domain and the TSN sub-network.  Within the TSN sub-network the TSN-aware MPLS (DetNet) node has a TSN-aware Talker/Listener role, so TSN specific management and control plane functionalities must be implemented. There are many similarities in the management plane techniques used in DetNet and TSN, but that is not the case for the control plane protocols.  For example, RSVP-TE and MSRP behaves differently. Therefore management and control plane design is an important aspect of scenarios, where mapping between DetNet and TSN is required. In order to use a TSN sub-network between DetNet nodes, DetNet specific information must be converted to TSN sub-network specific ones.  DetNet flow ID and flow related parameters/requirements must be converted to a TSN Stream ID and stream related parameters/ requirements.  Note that, as the TSN sub-network is just a portion of the end2end DetNet path (i.e., single hop from MPLS perspective), some parameters (e.g., delay) may differ significantly.  Other parameters (like bandwidth) also may have to be tuned due to the L2 encapsulation used within the TSN sub-network. In some case it may be challenging to determine some TSN Stream related information.  For example, on a TSN-aware MPLS (DetNet) node that acts as a Talker, it is quite obvious which DetNet node is the Listener of the mapped TSN stream (i.e., the MPLS Next-Hop).  However it may be not trivial to locate the point/interface where that Listener is connected to the TSN sub-network.  Such attributes may require interaction between control and management plane functions and between DetNet and TSN domains. Mapping between DetNet flow identifiers and TSN Stream identifiers, if not provided explicitly, can be done by a TSN-aware MPLS (DetNet) node locally based on information provided for configuration of the TSN Stream identification functions (Mask-and-match Stream identification and active Stream identification function). Triggering the setup/modification of a TSN Stream in the TSN sub- network is an example where management and/or control plane interactions are required between the DetNet and TSN sub-network. TSN-unaware MPLS (DetNet) nodes make such a triggering even more complicated as they are fully unaware of the sub-network and run independently. Configuration of TSN specific functions (e.g., FRER) inside the TSN sub-network is a TSN domain specific decision and may not be visible in the DetNet domain.  Service protection interworking scenarios are left for further study. </ins> <del> [Editor's note: This section is TBD Covers Creation, mapping, removal of TSN Stream IDs, related parameters and,when needed, configuration of FRER.  Supported by management/control plane.  SEE sections in removed text file.] While management plane and control planes are traditionally considered separately, from the Data Plane perspective there is no practical difference based on the origin of flow provisioning information, and the DetNet architecture I-D.ietf-detnet-architecture refers to these collectively as the 'Controller Plane'.  This document therefore does not distinguish between information provided by distributed control plane protocols, e.g., RSVP-TE RFC3209 and RFC3473, or by centralized network management mechanisms, e.g., RestConf RFC8040, YANG RFC7950, and the Path Computation Element Communication Protocol (PCEP) I-D.ietf-pce-pcep-extension-for-pce- controller or any combination thereof.  Specific considerations and requirements for the DetNet Controller Plane are discussed below. 8. </del> <ins> 6. </ins> The security considerations of DetNet in general are discussed in I- <del> D.ietf-detnet-architecture and I-D.sdt-detnet-security.  Other security considerations will be added in a future version of this draft. </del> <ins> D.ietf-detnet-architecture and I-D.ietf-detnet-security.  DetNet IP data plane specific considerations are summarized in I-D.ietf-detnet- ip.  Encryption may provided by an underlying sub-net using MACSec IEEE802.1AE-2018 for DetNet IP over TSN flows. </ins> <del> 9. </del> <ins> 7. </ins> This document makes no IANA requests.

Discussion:
Similar structure and changes as in IP over TSN. Service protection interworking is out-of-scope.