lldptool(8)

💖 lldptool(8) — PFC 💖

okay bestie, this one's the lldptool page for PFC, and yes it lives on Linux. pull up a chair, we're doing TLV stuff ✨

🎀 NAME 🎀

PFC — show / manipulate PFC TLV configuration. that's it, that's the name, short and iconic 💅

✨ SYNOPSIS ✨

lldptool -t -i ethx -V PFC [ -c [ enableTx | willing | enabled | delay ]
]

lldptool -T -i ethx -V PFC <CONFIG_ARG=value ...>

    CONFIG_ARG:=

     enableTx=<yes|no>

     willing=<yes|no|0|1>

     enabled=<none|[0..7],[0..7],...>

     delay=<integer value>

like, first form is the read vibe, second form is the write vibe, and CONFIG_ARG is the little menu of things you can set 🍓

🌸 DESCRIPTION 🌸

the PFC TLV is used to display and set current PFC TLV attributes. display AND set. both. versatile queen 👑

👑 ARGUMENTS 👑

• enableTx — turns on the PFC TLV so it gets transmitted in the LLDP PDU for the interface you picked. put it in the mail, fr fr 📬
• willing — display or set the willing attribute. if you set it to yes and a peer TLV shows up, then the peer's PFC attributes get used. if you set it to no, then the locally configured attributes are the ones that count. basically: are you flexible or are you set in your ways 🙈
• enabled — display or set the priorities that have PFC enabled. when you're setting it, it takes a comma separated list of priorities to enable, or the string none to disable all priorities. none = the "i'm not doing this today" option 💀
• delay — display or set the delay attribute, which is what configures PFC thresholds in hardware buffers. here's the tea: if PFC is enabled and frames keep getting dropped because the hardware buffers are full, then bumping this value up may help. may. no promises, that's literally what it says 🫶

🔮 Theory of Operations 🔮

so the PFC TLV uses the Symmetric attribute passing state machine defined in IEEE 802.1Qaz. what that means for you, bestie, is that which attributes get used depends on the willing bit:

• if the willing bit is set to 1 and a peer TLV is received, then the peer's attributes get used
• if the willing bit is set to 0, the local attributes get used
• and when both the peer and the local configuration are willing? tie breaking scheme, baby. someone has to win ⚔️

for the detailed coverage, go read the specification. this page is giving you the highlights, not the whole novel 📖

🌈 EXAMPLE & USAGE 🌈

enable PFC for priorities 1, 2, and 4 on eth2

lldptool -T -i eth2 -V PFC enabled=1,2,4

disable PFC for all priorities on eth2

lldptool -T -i eth2 -V PFC enabled=none

display configuration of PFC enabled priorities for eth2

lldptool -t -i eth2 -V PFC -c enabled

display last transmitted PFC TLV on eth2

lldptool -t -i eth2 -V PFC

see how it's the same command with -t vs -T? lowercase t is "tell me", capital T is "do the thing". iykyk 😌

📚 SOURCE 📚

• IEEE 802.1Qaz (http://www.ieee802.org/1/pages/dcbridges.html)

🦋 NOTES 🦋

(nothing here, she's empty, we respect that 🌸)

👀 SEE ALSO 👀

lldptool(8), lldpad(8)

💜 AUTHOR 💜

John Fastabend

okay that's the whole page!! this came from open-lldp, dated August 2012 — yes she's an elder but she's still slaying, and honestly? iconic. go configure your priorities, bestie, i believe in you 💅✨💖