Hello, I have been selected as the Routing Directorate reviewer for this draft. The Routing Directorate seeks to review all routing or routing-related drafts as they pass through IETF last call and IESG review, and sometimes on special request. The purpose of the review is to provide assistance to the Routing ADs. For more information about the Routing Directorate, please see: http://trac.tools.ietf.org/area/rtg/trac/wiki/RtgDir Although these comments are primarily for the use of the Routing ADs, it would be helpful if you could consider them along with any other IETF Early Review/Last Call comments that you receive, and strive to resolve them through discussion or by updating the draft. Document: draft-ietf-raw-architecture-21 Reviewer: Acee Lindem Review Date: 10/29/2024 IETF LC End Date: Early Review Intended Status: Informational Summary: The document defines the problem that RAW solves and how it integrates with the DetNet control and networks planes. The first half of document is background information with the core material being the RAW Conceptual Model in section 4 and the RAW Control Loop in section 5. Since I haven't followed either the DetNet or RAW working groups, it is hard for me to make a technical judgement. However, both the model and control loop seemed technically reasonable and well-thought given my limited exposure. Major Issues: None Minor Issues: The use of capitalization seems inconsistent. For example, "Lane" is and "Path" are always capitalized, e.g., "protection Path". I changed some of these in the suggested edits. HARQ, oOAM, RSSI, LQI, and ETX are not defined nor do they have references. Is it “control plane” or “controller plane”? Nits: I've attached some editorial suggestions. Thanks, Acee *** draft-ietf-raw-architecture-21-orig.txt Sun Oct 27 13:51:53 2024 --- draft-ietf-raw-architecture-21.txt Wed Oct 30 14:43:44 2024 *************** *** 23,29 **** of constrained spectrum and energy while maintaining the expected connectivity properties, typically reliability and latency. The loop involves DetNet Operational Plane functions, with a new recovery ! Function and a new Point of Local Repair operation, that dynamically selects the DetNet path(s) for the future packets to route around local degradations and failures. --- 23,29 ---- of constrained spectrum and energy while maintaining the expected connectivity properties, typically reliability and latency. The loop involves DetNet Operational Plane functions, with a new recovery ! function and a new Point of Local Repair (PLR) operation, that dynamically selects the DetNet path(s) for the future packets to route around local degradations and failures. *************** *** 129,135 **** 4.2. RAW vs. Upper and Lower Layers . . . . . . . . . . . . . 26 4.3. RAW and DetNet . . . . . . . . . . . . . . . . . . . . . 27 5. The RAW Control Loop . . . . . . . . . . . . . . . . . . . . 30 ! 5.1. Routing Time Scale vs. Forwarding Time Scale . . . . . . 30 5.2. A OODA Loop . . . . . . . . . . . . . . . . . . . . . . . 32 5.3. Observe: The RAW OAM . . . . . . . . . . . . . . . . . . 33 5.4. Orient: The RAW-extended DetNet Operational Plane . . . . 35 --- 129,135 ---- 4.2. RAW vs. Upper and Lower Layers . . . . . . . . . . . . . 26 4.3. RAW and DetNet . . . . . . . . . . . . . . . . . . . . . 27 5. The RAW Control Loop . . . . . . . . . . . . . . . . . . . . 30 ! 5.1. Routing Time-Scale vs. Forwarding Time-Scale . . . . . . 30 5.2. A OODA Loop . . . . . . . . . . . . . . . . . . . . . . . 32 5.3. Observe: The RAW OAM . . . . . . . . . . . . . . . . . . 33 5.4. Orient: The RAW-extended DetNet Operational Plane . . . . 35 *************** *** 151,157 **** Deterministic Networking aims to provide bounded latency and eliminate congestion loss, even when co-existing with best-effort traffic. It is getting traction in various industries including ! professional A/V, manufacturing, online gaming, and smartgrid automation, with both cost savings and complexity benefits (e.g., vs. loads of point-to-point (P2P) cables). --- 151,157 ---- Deterministic Networking aims to provide bounded latency and eliminate congestion loss, even when co-existing with best-effort traffic. It is getting traction in various industries including ! professional A/V, manufacturing, online gaming, and smart grid automation, with both cost savings and complexity benefits (e.g., vs. loads of point-to-point (P2P) cables). *************** *** 263,271 **** RAW also reuses terminology defined for MPLS in [RFC4427] such as the term recovery as covering both Protection and Restoration, a number of recovery types. That document defines a number of concepts like ! recovery domain that are used in the RAW works, and creates the new term recovery graph. A recovery graph associates a topological graph ! with usage metadata that represent how the paths within the recovery graph are built. RAW also reuses terminology defined for RSVP-TE in [RFC4090] such as --- 263,271 ---- RAW also reuses terminology defined for MPLS in [RFC4427] such as the term recovery as covering both Protection and Restoration, a number of recovery types. That document defines a number of concepts like ! recovery domain that are used in the RAW mechanisms, and creates the new term recovery graph. A recovery graph associates a topological graph ! with usage metadata that represents how the paths within the recovery graph are built. RAW also reuses terminology defined for RSVP-TE in [RFC4090] such as *************** *** 291,299 **** deterministic trajectory. The concept of recovery graph is agnostic to the underlaying ! technology and applies but is not limited to any fully or partially wireless mesh. RAW specifies strict and loose recovery graphs ! depending on whether the path is fully controlled by RAW or traverses an opaque network where RAW cannot observe and control the individual hops. --- 291,299 ---- deterministic trajectory. The concept of recovery graph is agnostic to the underlaying ! technology and applies but is not limited to any full or partial wireless mesh. RAW specifies strict and loose recovery graphs ! depending on whether the path is fully controled by RAW or traverses an opaque network where RAW cannot observe and control the individual hops. *************** *** 342,348 **** OAM stands for Operations, Administration, and Maintenance, and covers the processes, activities, tools, and standards involved with ! operating, administering, managing and maintaining any system. This document uses the terms Operations, Administration, and Maintenance, in conformance with the 'Guidelines for the Use of the "OAM" Acronym in the IETF' [RFC6291] and the system observed by the RAW OAM is the --- 342,348 ---- OAM stands for Operations, Administration, and Maintenance, and covers the processes, activities, tools, and standards involved with ! operating, administering, managing, and maintaining any system. This document uses the terms Operations, Administration, and Maintenance, in conformance with the 'Guidelines for the Use of the "OAM" Acronym in the IETF' [RFC6291] and the system observed by the RAW OAM is the *************** *** 365,371 **** 2.2.2. Uplink ! Connection from end-devices to a data communication equipment. In the context of wireless, uplink refers to the connection between a station (STA) and a controller (AP) or a User Equipment (UE) to a Base Station (BS) such as a 3GPP 5G gNodeB (gNb). --- 365,371 ---- 2.2.2. Uplink ! Connection from end-devices to data communication equipment. In the context of wireless, uplink refers to the connection between a station (STA) and a controller (AP) or a User Equipment (UE) to a Base Station (BS) such as a 3GPP 5G gNodeB (gNb). *************** *** 419,436 **** In the context of this document, a path is observed by following one copy or one fragment of a packet that conserves its uniqueness and integrity. For instance, if C replicates to E and F and D eliminates ! on the way from A to B, a packet from A to B can experience 2 paths, ! A->C->E->D->B and A->C->F->D->B. The terms lane is used to clarify when dealing with such path. ! With DetNet and RAW, a packet may be duplicated, fragmented and ! network-coded, and the various byproducts may travel different paths that are not necessarily end-to-end between A and B; we refer to that ! complex experience as a DetNet path. As such, the DetNet path extends the above description of a path, but it still matches the experience of a packet that traverses the network. ! With RAW, that experience is subject to change from a packet to the next, but all the possible experiences are all contained within a finite set. Therefore, we introduce below the term of a recovery graph that coalesces that set and covers the overall topology where --- 419,436 ---- In the context of this document, a path is observed by following one copy or one fragment of a packet that conserves its uniqueness and integrity. For instance, if C replicates to E and F and D eliminates ! duplicates on the way from A to B, a packet from A to B can experience 2 paths, ! A->C->E->D->B and A->C->F->D->B. The term lane is used to clarify when dealing with such path. ! With DetNet and RAW, a packet may be duplicated, fragmented, and ! network-coded, and the various by-products may travel different paths that are not necessarily end-to-end between A and B; we refer to that ! complex scenario as a DetNet path. As such, the DetNet path extends the above description of a path, but it still matches the experience of a packet that traverses the network. ! With RAW, that experience is subject to change from one packet to the next, but all the possible experiences are all contained within a finite set. Therefore, we introduce below the term of a recovery graph that coalesces that set and covers the overall topology where *************** *** 467,473 **** +---------+ | IoT G/W | +---------+ ! EGR <=== Elimination at Egress | | /------/ \-------\ Wired backbone | | --- 467,473 ---- +---------+ | IoT G/W | +---------+ ! EGRESS <=== Elimination at Egress | | /------/ \-------\ Wired backbone | | *************** *** 481,487 **** \ o / o o o o o \ / o low power lossy network \/ o o o ! o IN <=== Replication at recovery graph Ingress | o <- source device --- 481,487 ---- \ o / o o o o o \ / o low power lossy network \/ o o o ! o INGRESS <=== Replication at recovery graph Ingress | o <- source device *************** *** 490,497 **** Redundancy Refining further, a recovery graph is defined as the coalescence of ! the collection of all the feasible DetNet Paths that a packet which ! flow is assigned to the recovery graph may be forwarded along. A packet that is assigned to the recovery graph experiences one of the feasible DetNet Paths based on the current selection by the PLR at the time the packet traverses the network. --- 490,497 ---- Redundancy Refining further, a recovery graph is defined as the coalescence of ! the collection of all the feasible DetNet Paths that a packet for which ! a flow is assigned to the recovery graph and may be forwarded. A packet that is assigned to the recovery graph experiences one of the feasible DetNet Paths based on the current selection by the PLR at the time the packet traverses the network. *************** *** 573,582 **** Uppercase: DetNet Relay nodes Lowercase: DetNet Transit nodes ! I ==> a ==> b ==> C : an forward Segment to targets F and o ! C ==> o ==> T: an forward Segment to target T (and/or U) G | n | U : a crossing Segment to targets G or U ! I --> F --> E : an forward Lane to targets T1, T2, and T3 I, a, b, C, F, G, H, E : a path to T1, T2, and/or T3 I, p, q, R, o, F, G, H, E : lane-crossing alternate path --- 573,582 ---- Uppercase: DetNet Relay nodes Lowercase: DetNet Transit nodes ! I ==> a ==> b ==> C : A forward Segment to targets F and o ! C ==> o ==> T: A forward Segment to target T (and/or U) G | n | U : a crossing Segment to targets G or U ! I --> F --> E : A forward Lane to targets T1, T2, and T3 I, a, b, C, F, G, H, E : a path to T1, T2, and/or T3 I, p, q, R, o, F, G, H, E : lane-crossing alternate path *************** *** 678,684 **** In the context of RAW, an SLA (service level agreement) is a contract between a provider (the network) and a client, the application flow, ! about measurable metrics such as latency boundaries, consecutive losses, and packet delivery ratio (PDR). 2.5.2. Service Level Objective --- 678,684 ---- In the context of RAW, an SLA (service level agreement) is a contract between a provider (the network) and a client, the application flow, ! defining measurable metrics such as latency boundaries, consecutive losses, and packet delivery ratio (PDR). 2.5.2. Service Level Objective *************** *** 692,705 **** 2.5.3. Service Level Indicator A service level indicator (SLI) measures the compliance of an SLO to ! the terms of the contract. It can be for instance the statistics of ! individual losses and losses in a row as time series.). ! 2.5.4. Reliability Reliability is a measure of the probability that an item (e.g., system, network) will perform its intended function with no failure ! for a stated period of time (or number of demands or load) under stated environmental conditions. In other words, reliability is the probability that an item will be in an uptime state (i.e., fully operational or ready to perform) for a stated mission, e.g., to --- 692,705 ---- 2.5.3. Service Level Indicator A service level indicator (SLI) measures the compliance of an SLO to ! the terms of the contract. It can be for instance, the statistics of ! individual losses and losses in a row as time series. ! 2.5.4. Reliability Reliability is a measure of the probability that an item (e.g., system, network) will perform its intended function with no failure ! for a stated period of time (or a stated number of demands or load) under stated environmental conditions. In other words, reliability is the probability that an item will be in an uptime state (i.e., fully operational or ready to perform) for a stated mission, e.g., to *************** *** 711,717 **** mission readiness (e.g., to provide an SLA), an uptime state with the likelihood of a recoverable downtime state. Availability is expressed as (uptime)/(uptime+downtime). Note that it is ! availability that addresses downtime (incl. time for maintenance, repair, and replacement activities) and not reliability. See more in [NASA2]. --- 711,717 ---- mission readiness (e.g., to provide an SLA), an uptime state with the likelihood of a recoverable downtime state. Availability is expressed as (uptime)/(uptime+downtime). Note that it is ! availability that addresses downtime (including time for maintenance, repair, and replacement activities) and not reliability. See more in [NASA2]. *************** *** 751,757 **** An active OAM packet is a Limited OAM packet when it observes the RAW operation over a node, a segment, or a DetNet Path of the recovery graph, though not from Ingress to Egress. It is injected in the ! datapath and extracted from the datapath around the particular function or subnetwork (e.g., around a relay providing a Service sub- layer replication point) that is being tested. --- 751,757 ---- An active OAM packet is a Limited OAM packet when it observes the RAW operation over a node, a segment, or a DetNet Path of the recovery graph, though not from Ingress to Egress. It is injected in the ! data path and extracted from the data path around the particular function or subnetwork (e.g., around a relay providing a Service sub- layer replication point) that is being tested. *************** *** 788,800 **** 2.6.7. Lower Layer information ! The RAW Operational Plane elements (OAM Supervisor and local CPF ! (lCPF)) may gather aggregated information from lower layers about e.g., link quality. This information may be obtained from inside the device using specialized API (e.g., L2 triggers) or via control protocols such as BFD [RFC5880] or DLEP [DLEP]. It may then be massaged and exported through oOAM messaging, and passed to the ! Controller Plane using the lCPF. 2.6.8. Additional References --- 788,800 ---- 2.6.7. Lower Layer information ! The RAW Operational Plane elements (OAM Supervisor and local Control Plane ! Function (lCPF)) may gather aggregated information from lower layers about e.g., link quality. This information may be obtained from inside the device using specialized API (e.g., L2 triggers) or via control protocols such as BFD [RFC5880] or DLEP [DLEP]. It may then be massaged and exported through oOAM messaging, and passed to the ! Control Plane using the lCPF. 2.6.8. Additional References *************** *** 809,815 **** 3.1.1. High Availability Engineering Principles The reliability criteria of a critical system pervades through its ! elements, and if the system comprises a data network then the data network is also subject to the inherited reliability and availability criteria. It is only natural to consider the art of high availability engineering and apply it to wireless communications in --- 809,815 ---- 3.1.1. High Availability Engineering Principles The reliability criteria of a critical system pervades through its ! elements, and if the system comprises a data network and then the data network is also subject to the inherited reliability and availability criteria. It is only natural to consider the art of high availability engineering and apply it to wireless communications in *************** *** 820,826 **** 1. elimination of each single point of failure 2. reliable crossover ! 3. prompt detection of failures as they occur. These principles are common to all high availability systems, not just ones with Internet technology at the center. Examples of both --- 820,826 ---- 1. elimination of each single point of failure 2. reliable crossover ! 3. prompt detection of failures as they occur These principles are common to all high availability systems, not just ones with Internet technology at the center. Examples of both *************** *** 846,861 **** in case of a failure. There is a rather open-ended issue over alternate routes -- for example, when links are cabled through the same conduit, they form a shared risk link group (SRLG), and share ! the same fate if the bundle is cut. The same effect can happen with virtual links that end up in a same physical transport through the games of encapsulation. In a same fashion, an interferer or an obstacle may affect multiple wireless transmissions at the same time, even between different sets of peers. Intermediate network Nodes such as routers, switches and APs, wire ! bundles and the air medium itself can become single points of failure. For High Availability, it is thus required to use ! physically link- and Node-disjoint paths; in the wireless space, it is also required to use the highest possible degree of diversity (time, space, code, frequency, channel width) in the transmissions over the air to combat the additional causes of transmission loss. --- 846,861 ---- in case of a failure. There is a rather open-ended issue over alternate routes -- for example, when links are cabled through the same conduit, they form a shared risk link group (SRLG), and share ! the same fate if the conduit is cut. The same effect can happen with virtual links that end up in a same physical transport through the games of encapsulation. In a same fashion, an interferer or an obstacle may affect multiple wireless transmissions at the same time, even between different sets of peers. Intermediate network Nodes such as routers, switches and APs, wire ! bundles, and the air medium itself can become single points of failure. For High Availability, it is thus required to use ! physically link-disjoint and Node-disjoint paths; in the wireless space, it is also required to use the highest possible degree of diversity (time, space, code, frequency, channel width) in the transmissions over the air to combat the additional causes of transmission loss. *************** *** 865,871 **** equipment. In a constrained network where the waste of energy and bandwidth should be minimized, an excessive use of redundant links must be avoided; for RAW this means that the extra bandwidth must be ! used wisely and with parsimony. 3.1.1.2. Reliable Crossover --- 865,871 ---- equipment. In a constrained network where the waste of energy and bandwidth should be minimized, an excessive use of redundant links must be avoided; for RAW this means that the extra bandwidth must be ! used wisely and efficiently. 3.1.1.2. Reliable Crossover *************** *** 904,916 **** provide the required guarantees. The Data Plane must be configured with a sufficient degree of redundancy to select an alternate redundant path immediately upon a fault, without the need for a slow ! intervention from the Controller Plane. 3.1.1.3. Prompt Notification of Failures The execution of the two above principles is likely to render a ! system where the user rarely sees a failure. But someone needs to in ! order to direct maintenance. There are many reasons for system monitoring (FCAPS for fault, configuration, accounting, performance, security is a handy mental --- 904,916 ---- provide the required guarantees. The Data Plane must be configured with a sufficient degree of redundancy to select an alternate redundant path immediately upon a fault, without the need for a slow ! intervention from the Control Plane. 3.1.1.3. Prompt Notification of Failures The execution of the two above principles is likely to render a ! system where the user rarely sees a failure. But someone needs to observe ! the failure in order to direct maintenance. There are many reasons for system monitoring (FCAPS for fault, configuration, accounting, performance, security is a handy mental *************** *** 929,935 **** Those measurements are needed in the context of RAW to inform the controller and make the long-term reactive decision to rebuild a recovery graph based on statistical and aggregated information. RAW ! itself operates in the DetNet Network Plane at a faster time scale with live information on speed, state, etc... This live information can be obtained directly from the lower layer, e.g., using L2 triggers, read from a protocol such as the Dynamic Link Exchange --- 929,935 ---- Those measurements are needed in the context of RAW to inform the controller and make the long-term reactive decision to rebuild a recovery graph based on statistical and aggregated information. RAW ! itself operates in the DetNet Network Plane at a faster time-scale with live information on speed, state, etc... This live information can be obtained directly from the lower layer, e.g., using L2 triggers, read from a protocol such as the Dynamic Link Exchange *************** *** 941,947 **** The terms Reliability and Availability are defined for use in RAW in Section 2 and the reader is invited to read [NASA1] and [NASA2] for more details on the general definition of Reliability. Practically ! speaking a number of nines is often used to indicate the reliability of a data link, e.g., 5 nines indicate a Packet Delivery Ratio (PDR) of 99.999%. --- 941,947 ---- The terms Reliability and Availability are defined for use in RAW in Section 2 and the reader is invited to read [NASA1] and [NASA2] for more details on the general definition of Reliability. Practically ! speaking, a number of nines is often used to indicate the reliability of a data link, e.g., 5 nines indicate a Packet Delivery Ratio (PDR) of 99.999%. *************** *** 1071,1077 **** (frequency diversity) and diverse PHY technologies, e.g., narrowband vs. spread spectrum, or diverse codes. Using time diversity defeats short-term interferences; spatial diversity combats very local causes ! such as multipath fading; narrowband and spread spectrum are relatively innocuous to one another and can be used for diversity in the presence of the other. --- 1071,1077 ---- (frequency diversity) and diverse PHY technologies, e.g., narrowband vs. spread spectrum, or diverse codes. Using time diversity defeats short-term interferences; spatial diversity combats very local causes ! of interference such as multipath fading; narrowband and spread spectrum are relatively innocuous to one another and can be used for diversity in the presence of the other. *************** *** 1081,1087 **** [RFC8557] applies to both the wired and the wireless media, the methods to achieve RAW must extend those used to support time- sensitive networking over wires, as a RAW solution has to address ! less consistent transmissions, energy conservation and shared spectrum efficiency. Operating at the Layer-3, RAW does not change the wireless technology --- 1081,1087 ---- [RFC8557] applies to both the wired and the wireless media, the methods to achieve RAW must extend those used to support time- sensitive networking over wires, as a RAW solution has to address ! less consistent transmissions, energy conservation, and shared spectrum efficiency. Operating at the Layer-3, RAW does not change the wireless technology *************** *** 1096,1102 **** RAW extends the DetNet services by providing elements that are specialized for transporting IP flows over deterministic radio technologies such as listed in [RAW-TECHNOS]. Conceptually, RAW is ! agnostic to the radio layer underneath though the capability to schedule transmissions is assumed. How the PHY is programmed to do so, and whether the radio is single-hop or meshed, are unknown at the IP layer and not part of the RAW abstraction. Nevertheless, cross- --- 1096,1102 ---- RAW extends the DetNet services by providing elements that are specialized for transporting IP flows over deterministic radio technologies such as listed in [RAW-TECHNOS]. Conceptually, RAW is ! agnostic to the radio-layer underneath though the capability to schedule transmissions is assumed. How the PHY is programmed to do so, and whether the radio is single-hop or meshed, are unknown at the IP layer and not part of the RAW abstraction. Nevertheless, cross- *************** *** 1104,1111 **** (think, link quality) and packet handling (think, scheduling). The "Deterministic Networking Architecture" [RFC8655] is composed of ! three planes: the Application (User) Plane, the Controller Plane, and ! the Network Plane. The DetNet Network Plane is composed a Dataplane (packet forwarding) and an Operational Plane where OAM operations take place. In the Network Plane, the DetNet service sub-layer focuses on flow protection (e.g., using redundancy) and can be fully --- 1104,1111 ---- (think, link quality) and packet handling (think, scheduling). The "Deterministic Networking Architecture" [RFC8655] is composed of ! three planes: the Application (User) Plane, the Control Plane, and ! the Network Plane. The DetNet Network Plane is composed of a Dataplane (packet forwarding) and an Operational Plane where OAM operations take place. In the Network Plane, the DetNet service sub-layer focuses on flow protection (e.g., using redundancy) and can be fully *************** *** 1126,1132 **** one or multiple hops of homogeneous or heterogeneous wired and wireless technologies. RAW adds reactivity to the DetNet Forwarding sub-layer to compensate the dynamics for the radio links in terms of ! lossiness and bandwidth. This may apply for instance to mesh networks as illustrated in Figure 4, or diverse radio access networks as illustrated in Figure 10. --- 1126,1132 ---- one or multiple hops of homogeneous or heterogeneous wired and wireless technologies. RAW adds reactivity to the DetNet Forwarding sub-layer to compensate the dynamics for the radio links in terms of ! lossiness and bandwidth. This may apply, for instance, to mesh networks as illustrated in Figure 4, or diverse radio access networks as illustrated in Figure 10. *************** *** 1142,1167 **** Those capabilities include: Promiscuous Overhearing: Because the medium is broadcast as opposed ! to physically point to point like a wire, more than one node in the forward direction of the packet may hear or overhear a transmission, and the reception by one may compensate the loss by ! another. The concept of path can be revisited in favor multipoint to multipoint progress in the forward direction and statistical chances of successful reception of any of the transmissions by any of the receivers. ! L2-aware routing: As the quality and speed of a link variates over ! time, the concept of metric must also be revisited. Shortest path loses its absolute value, and hop count turns into a bad idea as the link budget drops with the distance. Routing over radio requires both 1) a new and more dynamic sense of the link, with ! new protocols such as DLEP and L2-trigger to maintain L3 up to date with the link quality and availability, and 2) a new approach to multipath routing, where non-equal cost multipath becomes the ! norm as shortest path loses its meaning with the instability of the metrics. ! ARQ, FEC and codes: Though feasible on any technology, proactive --- 1142,1167 ---- Those capabilities include: Promiscuous Overhearing: Because the medium is broadcast as opposed ! to physically point-to-point like a wire, more than one node in the forward direction of the packet may hear or overhear a transmission, and the reception by one may compensate the loss by ! another. The concept of path can be revisited in favor of multipoint to multipoint progress in the forward direction and statistical chances of successful reception of any of the transmissions by any of the receivers. ! L2-aware routing: As the quality and speed of a link varies over ! time, the concept of metric must also be revisited. Shortest-path loses its absolute value, and hop count turns into a bad idea as the link budget drops with the distance. Routing over radio requires both 1) a new and more dynamic sense of the link, with ! new protocols such as DLEP and L2-trigger to keep L3 up to date with the link quality and availability, and 2) a new approach to multipath routing, where non-equal cost multipath becomes the ! norm as shortest-path loses its meaning with the instability of the metrics. ! ARQ, FEC, and codes: Though feasible on any technology, proactive *************** *** 1184,1190 **** the extra transmission happens within the budget allocated to that hop, or that the introduced delay is compensated along the path. In the case of coded fragments and retries, it makes sense to ! variate all the possible physical properties of the transmission to reduce the chances that the same effect causes the loss of both original and redundant transmissions. --- 1184,1190 ---- the extra transmission happens within the budget allocated to that hop, or that the introduced delay is compensated along the path. In the case of coded fragments and retries, it makes sense to ! vary all the possible physical properties of the transmission to reduce the chances that the same effect causes the loss of both original and redundant transmissions. *************** *** 1195,1203 **** the signal quality, compensating for either distance or physical objects in the Fresnel zone that would reduce the link budget. ! RAW and DetNet route application flows that require a special treatment along the paths that provide that treatment. This may be ! seen as a form of Path Aware Networking and may be subject to impediments documented in [RFC9049]. The establishment of a path is not in-scope for RAW. It may be, --- 1195,1203 ---- the signal quality, compensating for either distance or physical objects in the Fresnel zone that would reduce the link budget. ! RAW and DetNet route application flows are flows that require a special treatment along the paths that provide that treatment. This may be ! seen as a form of Path-Aware Networking and may be subject to impediments documented in [RFC9049]. The establishment of a path is not in-scope for RAW. It may be, *************** *** 1216,1228 **** solutions are to be used for a given packet based on the current conditions. ! RAW distinguishes the longer time scale at which routes are computed ! from the shorter time scale where forwarding decisions are made. For ! a limited time, RAW Network Plane operations happen at a time scale ! that sits between the routing and the forwarding time scales, on one DetNet flow, to select a DetNet path within the resources delineated by a recovery graph (see Section 2.3.2). The recovery graph is ! preestablished and installed by means outside of the scope of RAW; it may be strict or loose depending on whether each or just a subset of the hops are observed and controlled by RAW. --- 1216,1228 ---- solutions are to be used for a given packet based on the current conditions. ! RAW distinguishes the longer time-scale at which routes are computed ! from the shorter time-scale where forwarding decisions are made. For ! a limited time, RAW Network Plane operations happen at a time-scale ! that sits between the routing and the forwarding time-scales, on one DetNet flow, to select a DetNet path within the resources delineated by a recovery graph (see Section 2.3.2). The recovery graph is ! pre-established and installed by means outside of the scope of RAW; it may be strict or loose depending on whether each or just a subset of the hops are observed and controlled by RAW. *************** *** 1247,1253 **** compute, install, and maintain the recovery graphs, e.g., by generating knowledge and wisdom such as a trained model for link quality prediction, which in turn can be used by the lCPF to ! Orient the Path selection by the PLR within the RAW OODA loop. 3. A PLR that hosts the Decision function of which DetNet Paths to use for the future packets that are routed within the recovery --- 1247,1253 ---- compute, install, and maintain the recovery graphs, e.g., by generating knowledge and wisdom such as a trained model for link quality prediction, which in turn can be used by the lCPF to ! orient the Path selection by the PLR within the RAW OODA loop. 3. A PLR that hosts the Decision function of which DetNet Paths to use for the future packets that are routed within the recovery *************** *** 1256,1263 **** 4. Service protection actions that operate at the DetNet Service sub-layer to increase the reliability of the end-to-end transmissions. The RAW architecture also covers in-situ ! signaling when the decision is Acted by a node that is downstream ! in the recovery graph from the PLR. The overall OODA Loop optimizes the use of redundancy to achieve the required reliability and availability Service Level Agreement (SLA) --- 1256,1263 ---- 4. Service protection actions that operate at the DetNet Service sub-layer to increase the reliability of the end-to-end transmissions. The RAW architecture also covers in-situ ! signaling when the decision is acted upon by a node that is ! downstream in the recovery graph from the PLR. The overall OODA Loop optimizes the use of redundancy to achieve the required reliability and availability Service Level Agreement (SLA) *************** *** 1322,1329 **** 4.1. The RAW Planes ! A RAW Network Plane may be strict (as illustrated in Figure 6 or ! loose (as illustrated in Figure 7, depending on whether RAW observes and takes actions on all hops or not. For instance, the packets between two wireless entities may be relayed over a wired infrastructure, in which case RAW observes and controls the --- 1322,1329 ---- 4.1. The RAW Planes ! A RAW Network Plane may be strict (as illustrated in Figure 6) or ! loose (as illustrated in Figure 7), depending on whether RAW observes and takes actions on all hops or not. For instance, the packets between two wireless entities may be relayed over a wired infrastructure, in which case RAW observes and controls the *************** *** 1391,1397 **** forwarding sub-layer operations are enforced end-to-end * The recovery graph may be expressed loosely to enable traversing a ! non-RAW subnetwork as in Figure 7. In that case, RAW can not leverage end-to-end DetNet and cannot provide latency guarantees. --- 1391,1397 ---- forwarding sub-layer operations are enforced end-to-end * The recovery graph may be expressed loosely to enable traversing a ! non-RAW subnetwork as in Figure 7. In that case, RAW cannot leverage end-to-end DetNet and cannot provide latency guarantees. *************** *** 1408,1414 **** depends dynamically on the PHY mode), number of flows (bandwidth that can be reserved for a flow depends on the number and size of flows sharing the spectrum) and average and mean squared deviation of ! availability and reliability figures such as Packet Delivery Ratio (PDR) over long periods of time. Based on those metrics, the DetNet rCPF installs the recovery graph --- 1408,1414 ---- depends dynamically on the PHY mode), number of flows (bandwidth that can be reserved for a flow depends on the number and size of flows sharing the spectrum) and average and mean squared deviation of ! availability and reliability metrics, such as, Packet Delivery Ratio (PDR) over long periods of time. Based on those metrics, the DetNet rCPF installs the recovery graph *************** *** 1416,1422 **** Plane can reliably deliver the packets within a System Level Agreement (SLA) associated to the flows that it transports. The SLA defines end-to-end reliability and availability requirements, where ! reliability may be expressed as a successful delivery in order and within a bounded delay of at least one copy of a packet. Depending on the use case and the SLA, the recovery graph may --- 1416,1422 ---- Plane can reliably deliver the packets within a System Level Agreement (SLA) associated to the flows that it transports. The SLA defines end-to-end reliability and availability requirements, where ! reliability may be expressed as a successful in-order delivery and within a bounded delay of at least one copy of a packet. Depending on the use case and the SLA, the recovery graph may *************** *** 1436,1442 **** RAW improves the reliability of transmissions and the availability of the communication resources, but does not provide scheduling and ! shaping, so RAW itself does not provide guarantees such as latency for the application payload. Rather, it should be seen as a dynamic optimization of the use of redundancy to maintain it within certain boundaries. For instance, ARQ is operated by the lower layers and --- 1436,1442 ---- RAW improves the reliability of transmissions and the availability of the communication resources, but does not provide scheduling and ! shaping, so RAW itself does not provide guarantees, such as, latency for the application payload. Rather, it should be seen as a dynamic optimization of the use of redundancy to maintain it within certain boundaries. For instance, ARQ is operated by the lower layers and *************** *** 1448,1454 **** times that match the contract with the DetNet sub-layers and the layers below. Excess of incoming traffic at the DetNet Ingress causes either dropping, queueing, or reclassification of the packets, ! and entail loss, latency, or jitter, and moot the guarantees that are provided inside the DetNet Network. --- 1448,1454 ---- times that match the contract with the DetNet sub-layers and the layers below. Excess of incoming traffic at the DetNet Ingress causes either dropping, queueing, or reclassification of the packets, ! and entail loss, latency, or jitter, and negate the guarantees that are provided inside the DetNet Network. *************** *** 1460,1466 **** When the traffic from upper layers matches the expectation of the lower layers, RAW still depends on the lower layers to provide the ! timing and physical resources guarantees that are needed to match the traffic SLA. When the availability of the physical resource varies, RAW acts on the distribution of the traffic to leverage alternates within a finite set of potential resources. --- 1460,1466 ---- When the traffic from upper layers matches the expectation of the lower layers, RAW still depends on the lower layers to provide the ! timing and physical resource guarantees that are needed to match the traffic SLA. When the availability of the physical resource varies, RAW acts on the distribution of the traffic to leverage alternates within a finite set of potential resources. *************** *** 1468,1474 **** 4.3. RAW and DetNet RAW leverages the DetNet Forwarding sub-layer and requires the ! support of OAM in DetNet Transit Nodes (see fig 3 of [RFC8655] for the dynamic acquisition of link capacity and state to maintain a strict RAW service, end-to-end, over a DetNet Network. RAW extends DetNet to improve the protection against link errors such as --- 1468,1474 ---- 4.3. RAW and DetNet RAW leverages the DetNet Forwarding sub-layer and requires the ! support of OAM in DetNet Transit Nodes (see figure 3 of [RFC8655] for the dynamic acquisition of link capacity and state to maintain a strict RAW service, end-to-end, over a DetNet Network. RAW extends DetNet to improve the protection against link errors such as *************** *** 1478,1495 **** available path diversity exceeds 1+1 linear redundancy. RAW adds sub-layer functions that operate in the DetNet Operational ! Plane. The RAW functions such as lCPF and OAM typically run only in the DetNet Ingress Edge Node or End System, though it may also run in DetNet Relay Nodes when the RAW operations are distributed along the recovery graph. The RAW functions include the PLR, which decides the ! DetNet Path for the future packets of a flows along the DetNet Path, and the OAM Supervisor, which triggers, and learns from, OAM observations, and feeds the PLR for its next decision. ! As illustrated in Figure 5, RAW extends the DetNet Stack (see fig 4 of [RFC8655] and Figure 3) with additional functionality at the DetNet Service sub-layer for the actuation of PREOF based on the PLR ! decision. Layer-3 in general and DetNet in particular operates on abstractions of the lower layers and through APIs to control those abstractions. For instance, DetNet already leverages lower layers for time-sensitive operations such as time synchronization and --- 1478,1495 ---- available path diversity exceeds 1+1 linear redundancy. RAW adds sub-layer functions that operate in the DetNet Operational ! Plane. The RAW functions, such as lCPF, and OAM typically run only in the DetNet Ingress Edge Node or End System, though it may also run in DetNet Relay Nodes when the RAW operations are distributed along the recovery graph. The RAW functions include the PLR, which decides the ! DetNet Path for future packets of a flow along the DetNet Path, and the OAM Supervisor, which triggers, and learns from, OAM observations, and feeds the PLR for its next decision. ! As illustrated in Figure 5, RAW extends the DetNet Stack (see figure 4 of [RFC8655] and Figure 3) with additional functionality at the DetNet Service sub-layer for the actuation of PREOF based on the PLR ! decision. In general, Layer-3 and DetNet, in particular, operates on abstractions of the lower layers and through APIs to control those abstractions. For instance, DetNet already leverages lower layers for time-sensitive operations such as time synchronization and *************** *** 1501,1508 **** abstraction to the DetNet layer. The RAW API can be used to push reliability and timing hints like suggest X retries (min, max) within a time window, or send unicast (one next hop) or multicast (for ! overhearing). The other way +-+ around RAW needs hints about the ! radio conditions like L2 triggers (RSSI, LQI, ETX…) over all the wireless hops. This information is useful to both the lCPF and the PLR. --- 1501,1508 ---- abstraction to the DetNet layer. The RAW API can be used to push reliability and timing hints like suggest X retries (min, max) within a time window, or send unicast (one next hop) or multicast (for ! overhearing). The other way around, RAW needs hints about the ! radio conditions like L2 triggers (RSSI, LQI, ETX) over all the wireless hops. This information is useful to both the lCPF and the PLR. *************** *** 1557,1563 **** Figure 5: RAW functions in the DetNet sub-layers There are 2 main proposed models to deploy RAW and DetNet. In the ! first model (strict) illustrated in Figure 6, RAW operates over a continuous DetNet Service end-to-end between the Ingress and the Egress Edge Nodes or End Systems. --- 1557,1563 ---- Figure 5: RAW functions in the DetNet sub-layers There are 2 main proposed models to deploy RAW and DetNet. In the ! first model (strict) (illustrated in Figure 6), RAW operates over a continuous DetNet Service end-to-end between the Ingress and the Egress Edge Nodes or End Systems. *************** *** 1607,1613 **** In the loose model, RAW cannot observe the hops in network, and the path beyond the first hop is opaque; RAW can still observe the end- to-end behavior and use Layer-3 measurements to decide whether to ! replicate a packet and select the first hop interface(s). --- 1607,1613 ---- In the loose model, RAW cannot observe the hops in network, and the path beyond the first hop is opaque; RAW can still observe the end- to-end behavior and use Layer-3 measurements to decide whether to ! replicate a packet and select the first-hop interface(s). *************** *** 1650,1656 **** 5. The RAW Control Loop ! 5.1. Routing Time Scale vs. Forwarding Time Scale With DetNet, the Controller Plane Function handles the routing computation and maintenance. With RAW, the routing part of the CPF --- 1650,1656 ---- 5. The RAW Control Loop ! 5.1. Routing Time-Scale vs. Forwarding Time-Scale With DetNet, the Controller Plane Function handles the routing computation and maintenance. With RAW, the routing part of the CPF *************** *** 1659,1665 **** extended to generate the information required by the lCPF, which acts as the orientation component in the loop. The rCPF may, e.g., propose DetNet Paths to be used as a reflex action in response to ! network events, or by provide aggregated history that the lCPF can use to make an oriented decision. In a wireless mesh, the path to the DetNet CPF can be expensive and --- 1659,1665 ---- extended to generate the information required by the lCPF, which acts as the orientation component in the loop. The rCPF may, e.g., propose DetNet Paths to be used as a reflex action in response to ! network events, or by providing aggregated history that the lCPF can use to make an oriented decision. In a wireless mesh, the path to the DetNet CPF can be expensive and *************** *** 1690,1698 **** link quality indicator, or a boolean value for either up or down. The interaction with the (remote) RAW rCPF is handled by the lCPF, ! which builds reports to the rCPF and digests the control information ! back, to be used inside a forwarding control loop for traffic ! steering. +----------------+ --- 1690,1698 ---- link quality indicator, or a boolean value for either up or down. The interaction with the (remote) RAW rCPF is handled by the lCPF, ! which builds reports to the rCPF and sends control information ! back to the RAW node, to be used inside a forwarding control loop for ! traffic steering. +----------------+ *************** *** 1725,1731 **** *** = flapping at this time ! Figure 8: Time Scales In the case of wireless, the changes that affect the forwarding decision can happen frequently and often for short durations, e.g., a --- 1725,1731 ---- *** = flapping at this time ! Figure 8: Time-Scales In the case of wireless, the changes that affect the forwarding decision can happen frequently and often for short durations, e.g., a *************** *** 1738,1744 **** Internet-Draft RAW Architecture October 2024 ! the line of sight transmission for a few seconds, or a radar measures the depth of a pool and interferes on a particular channel for a split second. --- 1738,1744 ---- Internet-Draft RAW Architecture October 2024 ! the line-of-sight transmission for a few seconds, or radar measures the depth of a pool and interferes on a particular channel for a split second. *************** *** 1753,1760 **** In the context of Traffic Engineering (TE), an alternate path can be used upon the detection of a failure in the main path, e.g., using OAM in MPLS-TP or BFD over a collection of SD-WAN tunnels. RAW ! formalizes a forwarding time scale that is an order(s) of magnitude ! shorter than the controller plane routing time scale, and separates the protocols and metrics that are used at both scales. Routing can operate on long-term statistics such as delivery ratio over minutes to hours, but as a first approximation can ignore flapping. On the --- 1753,1760 ---- In the context of Traffic Engineering (TE), an alternate path can be used upon the detection of a failure in the main path, e.g., using OAM in MPLS-TP or BFD over a collection of SD-WAN tunnels. RAW ! formalizes a forwarding time-scale that is an order(s) of magnitude ! shorter than the control plane routing time-scale, and separates the protocols and metrics that are used at both scales. Routing can operate on long-term statistics such as delivery ratio over minutes to hours, but as a first approximation can ignore flapping. On the *************** *** 1762,1772 **** packet rate, and uses information that must be pertinent at the present time for the current transmission(s). ! 5.2. A OODA Loop OODA (Observe, Orient, Decide, Act) is a generic formalism to represent the operational steps in a Control Loop. The RAW ! Architecture applies that generic model to continuously optimize the spectrum and energy used to forward packets within a recovery graph, instantiating the OODA steps as follows: --- 1762,1772 ---- packet rate, and uses information that must be pertinent at the present time for the current transmission(s). ! 5.2. An OODA Loop OODA (Observe, Orient, Decide, Act) is a generic formalism to represent the operational steps in a Control Loop. The RAW ! Architecture applies to a generic model to continuously optimize the spectrum and energy used to forward packets within a recovery graph, instantiating the OODA steps as follows: *************** *** 1838,1844 **** point downstream before it reaches the egress. This observation feeds the RAW PLR that makes the decision on which ! path is used at which RAW Node, for one a small continuous series of packets. --- 1838,1844 ---- point downstream before it reaches the egress. This observation feeds the RAW PLR that makes the decision on which ! path is used at which RAW Node, for one, a small continuous series of packets. *************** *** 1869,1893 **** Figure 10: Observed Links in Radio Access Protection ! In the case of an End-to-End Protection in a Wireless Mesh, the recovery graph is strict and congruent with the path so all links are observed. ! Conversely, in the case of Radio Access Protection illustrated in Figure 10, the recovery graph is Loose and only the first hop is observed; the rest of the path is abstracted and considered ! infinitely reliable. The loss of a packet is attributed to the first ! hop Radio Access Network (RAN), even if a particular loss effectively ! happens farther down the path. In that case, RAW enables technology ! diversity (e.g., Wi-Fi and 5G) which in turn improves the diversity ! in spectrum usage. The Links that are not observed by OAM are opaque to it, meaning that the OAM information is carried across and possibly echoed as data, but there is no information capture in intermediate nodes. In the example above, the Tunnel underlay is opaque and not controlled by RAW; still the RAW OAM measures the end-to-end latency and delivery ! ratio for packets sent via RAN 1, RAN 2 and RAN 3, and determines whether a packet should be sent over either or a collection of those access links. --- 1869,1893 ---- Figure 10: Observed Links in Radio Access Protection ! In the case of End-to-End Protection in a Wireless Mesh, the recovery graph is strict and congruent with the path so all links are observed. ! Conversely, in the case of Radio Access Protection, illustrated in Figure 10, the recovery graph is Loose and only the first hop is observed; the rest of the path is abstracted and considered ! infinitely reliable. The loss of a packet is attributed to the ! first-hop Radio Access Network (RAN), even if a particular loss ! effectively happens farther down the path. In that case, RAW enables ! technology diversity (e.g., Wi-Fi and 5G) which in turn improves ! the diversity in spectrum usage. The Links that are not observed by OAM are opaque to it, meaning that the OAM information is carried across and possibly echoed as data, but there is no information capture in intermediate nodes. In the example above, the Tunnel underlay is opaque and not controlled by RAW; still the RAW OAM measures the end-to-end latency and delivery ! ratio for packets sent via RAN 1, RAN 2, and RAN 3, and determines whether a packet should be sent over either or a collection of those access links. *************** *** 1908,1923 **** 5.4. Orient: The RAW-extended DetNet Operational Plane ! RAW separates the long time scale at which a recovery graph is ! elaborated and installed, from the short time scale at which the ! forwarding decision is taken for one or a few packets (see in Section 5.1) that experience the same path until the network conditions evolve and another path is selected within the same recovery graph. The recovery graph computation is out of scope, but RAW expects that the CPF that installs the recovery graph also provides related ! knowledge in the form of meta data about the links, segments and possible DetNet Paths. That meta data can be a pre-digested statistical model, and may include prediction of future flaps and packet loss, as well as recommended actions when that happens. --- 1908,1923 ---- 5.4. Orient: The RAW-extended DetNet Operational Plane ! RAW separates the long time-scale at which a recovery graph is ! elaborated and installed, from the short time-scale at which the ! forwarding decision is taken for one or a few packets (see Section 5.1) that experience the same path until the network conditions evolve and another path is selected within the same recovery graph. The recovery graph computation is out of scope, but RAW expects that the CPF that installs the recovery graph also provides related ! knowledge in the form of meta data about the links, segments, and possible DetNet Paths. That meta data can be a pre-digested statistical model, and may include prediction of future flaps and packet loss, as well as recommended actions when that happens. *************** *** 1925,1950 **** The meta data may include: * A set of Pre-Determined DetNet Paths that are prepared to match ! expected link degradation profiles, so the DDCPEs can take reflex rerouting actions when facing a degradation that matches one such profile. ! * Link Quality Statistics history and pre-trained models, e.g., to predict the short-term variation of quality of the links in a recovery graph The recovery graph is installed with measurable objectives that are computed by the rCPF to achieve the RAW SLA. The objectives can be ! expressed as any of maximum number of packet lost in a row, bounded ! latency, maximal jitter, maximum number of interleaved out of order packets, average number of copies received at the elimination point, and maximal delay between the first and the last received copy of the same packet. 5.5. Decide: The Point of Local Repair ! The RAW OODA Loop operates at the path selection time scale to ! provide agility vs. the brute force approach of flooding the whole recovery graph. The OODA Loop controls, within the redundant solutions that are proposed by the local CPF, which is used for each packet to provide a Reliable and Available service while minimizing --- 1925,1950 ---- The meta data may include: * A set of Pre-Determined DetNet Paths that are prepared to match ! expected link-degradation profiles, so the DDCPEs can take reflex rerouting actions when facing a degradation that matches one such profile. ! * Link-Quality Statistics history and pre-trained models, e.g., to predict the short-term variation of quality of the links in a recovery graph The recovery graph is installed with measurable objectives that are computed by the rCPF to achieve the RAW SLA. The objectives can be ! expressed as any of the maximum number of packet lost in a row, bounded ! latency, maximal jitter, maximum number of interleaved out-of-order packets, average number of copies received at the elimination point, and maximal delay between the first and the last received copy of the same packet. 5.5. Decide: The Point of Local Repair ! The RAW OODA Loop operates at the path selection time-scale to ! provide agility vs. the brute-force approach of flooding the whole recovery graph. The OODA Loop controls, within the redundant solutions that are proposed by the local CPF, which is used for each packet to provide a Reliable and Available service while minimizing *************** *** 1965,1977 **** To that effect, RAW defines the Point of Local Repair (PLR), which performs rapid local adjustments of the forwarding tables within the diversity that the lCPF has in store for the recovery graph. The PLR ! enables to exploit the richer forwarding capabilities at a faster ! time scale over a portion of the recovery graph, in either a loose or a strict fashion. The PLR operates on metrics that evolve faster, but that need to be advertised at a fast rate but only locally, within the recovery ! graph, and reacts on the metrics updates by changing the DetNet path in use for the affected flows. The rapid changes in the forwarding decisions are made and contained --- 1965,1977 ---- To that effect, RAW defines the Point of Local Repair (PLR), which performs rapid local adjustments of the forwarding tables within the diversity that the lCPF has in store for the recovery graph. The PLR ! enables exploitation of the richer forwarding capabilities at a faster ! time-scale over a portion of the recovery graph, in either a loose or a strict fashion. The PLR operates on metrics that evolve faster, but that need to be advertised at a fast rate but only locally, within the recovery ! graph, and reacts on the metric updates by changing the DetNet path in use for the affected flows. The rapid changes in the forwarding decisions are made and contained *************** *** 1989,1995 **** +---------------+-------------------------+---------------------+ | Communication | Slow, expensive | Fast, local | +---------------+-------------------------+---------------------+ ! | Time Scale | routing computation + | lookup + FIB | | (order) | round trip, | installation, micro | | | milliseconds to seconds | to milliseconds | +---------------+-------------------------+---------------------+ --- 1989,1995 ---- +---------------+-------------------------+---------------------+ | Communication | Slow, expensive | Fast, local | +---------------+-------------------------+---------------------+ ! | Time-Scale | routing computation + | lookup + FIB | | (order) | round trip, | installation, micro | | | milliseconds to seconds | to milliseconds | +---------------+-------------------------+---------------------+ *************** *** 1997,2004 **** | | graphs to optimize | recovery graph | | | globally | | +---------------+-------------------------+---------------------+ ! | Considered | Averaged, Statistical, | Instant values / | ! | Metrics | Shade of grey | boolean condition | +---------------+-------------------------+---------------------+ Table 1: CPF vs. PLR --- 1997,2004 ---- | | graphs to optimize | recovery graph | | | globally | | +---------------+-------------------------+---------------------+ ! | Considered | Averaged, Statistical, |Instantaneous values | ! | Metrics | Shade of grey | /boolean condition | +---------------+-------------------------+---------------------+ Table 1: CPF vs. PLR *************** *** 2020,2027 **** The PLR sits in the DetNet Forwarding sub-Layer of Edge and Relay Nodes. The PLR it operates on the packet flow, learning the recovery ! graph and path selection information from the packet, possibly making ! local decision and retagging the packet to indicate so. On the other hand, the PLR interacts with the lower layers (through triggers and DLEP) and with its peers (through iOAM and oOAM) to obtain up-to-date information about its links and the quality of the overall recovery --- 2020,2027 ---- The PLR sits in the DetNet Forwarding sub-Layer of Edge and Relay Nodes. The PLR it operates on the packet flow, learning the recovery ! graph and path-selection information from the packet, possibly making ! a local decision and retagging the packet to indicate so. On the other hand, the PLR interacts with the lower layers (through triggers and DLEP) and with its peers (through iOAM and oOAM) to obtain up-to-date information about its links and the quality of the overall recovery *************** *** 2049,2055 **** Figure 11: PLR Interfaces ! 5.6. Act: DetNet Path Selection and reliability functions The main action by the PLR is the swapping of the DetNet Path within the recovery graph for the future packets. The candidate DetNet --- 2049,2055 ---- Figure 11: PLR Interfaces ! 5.6. Act: DetNet Path Selection and Reliability functions The main action by the PLR is the swapping of the DetNet Path within the recovery graph for the future packets. The candidate DetNet *************** *** 2057,2064 **** protection against different failures. The RAW API enriches the DetNet protection services (PREOF) with ! potential possibility to interact with lower layer one-hop ! reliability functions that are more typical to wireless than wires, including Automatic Repeat reQuest (ARQ), Forward Error Correction (FEC), Hybrid ARQ (HARQ) that includes both, and other techniques such as overhearing and constructive interferences. Because RAW may --- 2057,2064 ---- protection against different failures. The RAW API enriches the DetNet protection services (PREOF) with ! potential possibility to interact with lower-layer one-hop ! reliability functions that are more typical to wireless than wired, including Automatic Repeat reQuest (ARQ), Forward Error Correction (FEC), Hybrid ARQ (HARQ) that includes both, and other techniques such as overhearing and constructive interferences. Because RAW may *************** *** 2074,2081 **** Internet-Draft RAW Architecture October 2024 ! RAW provides hints to the lower layer services on the desired ! outcome, and the lower layer acts on those hinHts to provide the best approximation of that outcome, e.g., a level of reliability for one- hop transmission within a bounded budget of time and/or energy. Thus, the RAW API makes possible cross-layer optimization for --- 2074,2081 ---- Internet-Draft RAW Architecture October 2024 ! RAW provides hints to the lower-layer services on the desired ! outcome, and the lower layer acts on those hints to provide the best approximation of that outcome, e.g., a level of reliability for one- hop transmission within a bounded budget of time and/or energy. Thus, the RAW API makes possible cross-layer optimization for *************** *** 2090,2102 **** failures, and apply the appropriate DetNet paths for the current state of the wireless links. In the distributed approach, the signaling in the packet may be more abstract than an explicit Path, ! and the PLR decision might be revised along the select DetNet Path based on a better knowledge of the rest of the way. The dynamic DetNet Path selection in RAW avoids the waste of critical resources such as spectrum and energy while providing for the guaranteed SLA, e.g., by rerouting and/or adding redundancy only when ! a spike of loss is observed. 6. Security Considerations --- 2090,2102 ---- failures, and apply the appropriate DetNet paths for the current state of the wireless links. In the distributed approach, the signaling in the packet may be more abstract than an explicit Path, ! and the PLR decision might be revised along the selected DetNet Path based on a better knowledge of the rest of the way. The dynamic DetNet Path selection in RAW avoids the waste of critical resources such as spectrum and energy while providing for the guaranteed SLA, e.g., by rerouting and/or adding redundancy only when ! a loss spike is observed. 6. Security Considerations *************** *** 2109,2115 **** 6.1. Layer-2 encryption Radio networks typically encrypt at the MAC layer to protect the ! transmission. If the encryption is per pair of peers, then certain RAW operations like promiscuous overhearing become impossible. 6.2. Forced Access --- 2109,2115 ---- 6.1. Layer-2 encryption Radio networks typically encrypt at the MAC layer to protect the ! transmission. If the encryption is per-pair of peers, then certain RAW operations like promiscuous overhearing become impossible. 6.2. Forced Access