【正文】 ic as the maximum interference (AVB stream burst) for the highest nonAVB priority is limited and known ? Protects the AVB streams, as it limits the back to back AVB stream bursts which can interfere in a bridge ? The Credit Based Shaper in bination with the Stream Reservation Protocol is intended to provide delays under 250 us per bridge. IEEE 54 Credit Based Shaper Example IEEE 55 Preemption and Time Scheduled Queuing ? The credit based shaper works well for audio/video applications, but is not suitable for control applications where worst case delays must be reduced to a minimum. ? Timeaware (scheduled) queuing bined with preemption reduces delays to near the best theoretical levels, with the minimum impact on nonscheduled traffic. ? SRP or a management agent is required to provide an admission control scheme to limit lowlatency traffic to the amount that can be supported by the links in the path between a talker and corresponding listener(s) IEEE 56 Policing ? Every frame can be marked “green” or “yellow” using the Drop Eligible bit available for Stags and Btags, or a priority code point in Ctags. ? Policing is done per input port, but only after it is determined that a frame can be delivered to some port. Frames that are dropped by the forwarding mechanism are not policed. ? Policing is twocolor in (green or yellow) and threecolor out (green, yellow, or red). Red are dropped. Yellow frames have a higher probability of being discarded than green frames. ? Policing algorithm is from Metro Ether Forum spec . IEEE 57 IETF 86 – Tutorial OTHER STANDARDS NOT COVERED BY THIS TUTORIAL March 10, 2023 IEEE 58 Link Aggregation [] ? Revision in progress ? Includes Distributed Resilient Network Interconnect (DRNI) ? No longer tied to – works over any real or virtual medium ? Supports one, two or three systems at each end of the aggregation ? Connects two works so that neither work is aware of the details of the interconnect ? Failures do not propagate from work to work ? Systems can be bridges, routers, end stations, or anything else ? Backwards patible with existing Link Aggregation ? Allows systems to negotiate which data streams take which path, so that bidirectionally congruent flows are possible, and so that extensive state synchronization (., of forwarding tables) is not necessary among systems ? Supports any means of identifying streams: VLANs, 5tuples, etc. IEEE 59 Link Layer Discovery Protocol (LLDP) [] ? LLDP is a link layer protocol used by work devices for advertising their identity, capabilities, and neighbors on an IEEE 802 local area work, principally wired Ether. ? Information Exchanged is in the form of TLVs and includes mandatory and optional information such as: ? System name and description ? Port name and description ? IP management address ? VLAN name ? System capabilities (switching, routing, etc.) ? MAC/PHY information ? MDI power ? Link aggregation ? LLDP is extensible and has been extended for DCB works (. VDP and DCBX). ? LLDP MIB is a continuation of the IETF work on Physical Topology MIB [RFC 2922] IEEE 60 BR A BR B BR C Time Synchronization [] ? Specifies distribution of precise timing ? Includes an IEEE 1588 Precision Time Protocol (PTP) profile that specifies timing transport over fullduplex IEEE links ? The interfaces are either a simplified, tightly controlled boundary clocks or ordinary clocks ? Also specifies transport over other media not covered in IETF 1588 ? IEEE WiFi ? IEEE Ether Passive Optical Network (EPON) ? Coordinated Shared Network (CSN) – . MoCA, ITUT IEEE 61 Audio Video Bridging Systems [] ? Provides profiles building works to transport timesensitive audio and/or video data streams ? Profiles cover features, options and configurations needed to meet latency targets IEEE 62 Bridge Port Extension [] ? Extended Bridge is formed by a Controlling Bridge plus attached Port Extenders ? Each port of a Port Extender is a virtual port of the Controlling Bridge ? All traffic is relayed by the Controlling Bridge ? Externally (including to work management, the Extended Bridge is a Bridge ? A Port Extender may be in an end system ? Port Extenders may be cascaded ? Multicast replication allows a frame to be replicated to selected ports by the Port Extenders IEEE 63 Bridge VM VM VM VM VM VM Security ? Portbased Network Access Control [] ? Defines encapsulation of Extensible Authentication Protocol (EAP) over IEEE 802 (EAP over LAN, or EAPOL). ? Widely deployed on both wired and WiFi works ? MAC Security (MACsec) [] ? MACsec secures a link not a conversation ? MACsec counters maninthemiddle attacks ? Secure Device Identity [] ? Supports trail of trust from manufacturer to user ? Defines how a Secure Device Identifier may be cryptographically bound to a device to support device identity authentication. IEEE 64 IETF 86 – Tutorial SUMMARY March 10, 2023 IEEE 65 Summary IEEE 66 Acknowledgements ? The authors would like to thank David Allan, Christian Boiger, Nigel Bragg, and Dan Romascanu for their review and contribution. IEEE 67 IETF 86 – Tutorial REFERENCES IEEE Standards – Interworking ? IEEE , “IEEE standard for local and metropolitan area works: Station and media access control connectivity discovery,” September 2023. ? IEEE , “IEEE standard for local and metropolitan area works: Link aggregation,” November 2023. ? IEEE , ”IEEE standard for local and metropolitan area works: Media access control (MAC) bridges,” June 2023. ? IEEE , “IEEE technical report and guidelines Part 5: Media access control (MAC) bridging of Ether in local area works,” May 2023, ? IEEE , ”IEEE standard for loca