On Thu, Sep 18, 2025 at 07:15:38AM +0200, Oleksij Rempel wrote: > +* **How it works**: To inhibit incoming data, a receiving device can force a > + collision on the line. When the sending station detects this collision, it > + terminates its transmission, sends a "jam" signal, and then executes the > + "Collision backoff and retransmission" procedure as defined in IEEE 802.3, > + Section 4.2.3.2.5. This algorithm makes the sender wait for a random > + period before attempting to retransmit. By repeatedly forcing collisions, > + the receiver can effectively throttle the sender's transmission rate. Please align the bullet list text. I see hanging indent instead there in htmldocs output. > +* **What it is**: A standard Ethernet frame with a globally reserved > + destination MAC address (``01-80-C2-00-00-01``). This address is in a range > + that standard IEEE 802.1D-compliant bridges do not forward. However, some > + unmanaged or misconfigured bridges have been reported to forward these > + frames, which can disrupt flow control across a network. > + > +* **How it works**: The frame contains a MAC Control opcode for PAUSE > + (``0x0001``) and a ``pause_time`` value, telling the sender how long to > + wait before sending more data frames. This time is specified in units of > + "pause quantum", where one quantum is the time it takes to transmit 512 bits. > + For example, one pause quantum is 51.2 microseconds on a 10 Mbit/s link, > + and 512 nanoseconds on a 1 Gbit/s link. A ``pause_time`` of zero indicates > + that the transmitter can resume transmission, even if a previous non-zero > + pause time has not yet elapsed. Same here. > +* **What it is**: PFC allows a receiver to pause traffic for one or more of the > + 8 standard priority levels without stopping traffic for other priorities. > + This is critical in data center environments for protocols that cannot > + tolerate packet loss due to congestion (e.g., Fibre Channel over Ethernet > + or RoCE). > + > +* **How it works**: PFC uses a specific PAUSE frame format. It shares the same > + globally reserved destination MAC address (``01-80-C2-00-00-01``) as legacy > + PAUSE frames but uses a unique opcode (``0x0101``). The frame payload > + contains two key fields: > + > + - **``priority_enable_vector``**: An 8-bit mask where each bit corresponds to > + one of the 8 priorities. If a bit is set to 1, it means the pause time > + for that priority is active. > + - **``time_vector``**: A list of eight 2-octet fields, one for each priority. > + Each field specifies the ``pause_time`` for its corresponding priority, > + measured in units of ``pause_quanta`` (the time to transmit 512 bits). Ditto. Thanks. -- An old man doll... just what I always wanted! - Clara