Hi!
My examples are just one way of having several matching criteria. Below, I use one match but with the pipe delimiter, I tell the match function (much like grep in Linux/UNIX) that I want to match text A or text B or text C. This is just normal regex, regular expressions.
show interfaces ge* extensive | match "MAC pause frames|MAC statistics|Physical"
There are, unfortunately, lots of implementations of regex but here is one quick guide: https://cs.lmu.edu/~ray/notes/regex/
Even cooler, in Junos, you can really stack multiple matches:
show chassis hardware | match "Chassis|Power Supply" | except "Power Supply [0-9] *$"
Meaning: find all lines with either "Chassis" or "Power Supply" in them, but exclude "Power Supply" lines with only spaces after that keyword. In my EX4100-F, the mge ports in the back can take power in as well, so they are listed as PSUs but with no serials etc, so I filtered them out as being not so interesting.
Here is one that is really stacked with two matches and one exclude:
show interfaces ge* extensive | match "Phys|Queue count|^ +([0-9]+ +){3}" | match "[a-z]|[0-9]{5,}" | except " +0$"
Now it's up to you to decipher it :) Hint: delete the second match and the exclude and see how that behaves, then add the second and the exclude, one by one. You will see what I do, in steps. This example is really a bit "synthetic", and can be done more nicely, but shows that you can use multiple match and exclude.
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Original Message:
Sent: 09-17-2025 16:00
From: JOHN WILLIAMSON
Subject: Common cause of MAC pause frames?
Thanks for the CLI commands. Is that how you can stack matches? That's the coolest part. So far, I haven't seen any flow control mismatches. I do find a decent amount of "drops" listed with no other errors and sometimes without pause frames. I haven't seen any from switch to switch.
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JOHN WILLIAMSON
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Original Message:
Sent: 09-17-2025 11:38
From: fb35523
Subject: Common cause of MAC pause frames?
Old-style Flow control is a mess. It was designed for 10 Mbps networks and is not of any use in modern networks. You can see if the switch sends or receives pause frames with this command (selecting only ge-interfaces, adapt as needed):
show interfaces ge* extensive | match "MAC pause frames|MAC statistics|Physical"
Here is the output from an EX4100-F linking with an EX2200 where the link uses flow control:
> show interfaces mge-0/2/0 extensive | match flow
Source filtering: Disabled, Flow control: Enabled, Auto-negotiation: Enabled, Remote fault: Online, Media type: Copper,
Link mode: Full-duplex, Flow control: Symmetric, Remote fault: OK, Link partner Speed: 1000 Mbps
Flow control: Symmetric, Flow control tx: Enabled, Flow control rx: Enabled, Remote fault: Link OK,
Here is a link from the EX4100 to a Mist AP where flow control is enabled but not used:
> show interfaces ge-0/0/1 extensive | match flow
Source filtering: Disabled, Flow control: Enabled, Auto-negotiation: Enabled, Remote fault: Online, Media type: Copper,
Link mode: Full-duplex, Flow control: None, Remote fault: OK, Link partner Speed: 1000 Mbps
Flow control: None, Flow control tx: Disabled, Flow control rx: Disabled, Remote fault: Link OK,
As you can see, flow control is enabled in the switch but since the AP doesn't use it (good call from Mist), the autoneg results in flow control not being used.
If you have any hesitation at all in regards to flow control, disable it! I'm not talking about the modern PFC style data center flow control, mind you, but that is a completely different beast.
Original Message:
Sent: 08-12-2025 18:16
From: JOHN WILLIAMSON
Subject: Common cause of MAC pause frames?
Generally, when I find bad cables, is when I get CRC and fragmented frames, and that sort of thing. There were no errors on these connections. All the devices have 1 GB network interfaces. Depending on the port on the switch, they could be on a 1-Gig port or a multigig port that can negotiate down.
I could look into what tests I can run to determine the cable age in the walls. I have a Fluke scanner for that. If they pass Cat5e or Cat6 tests, they should not be a cause of the issue.
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JOHN WILLIAMSON
Original Message:
Sent: 08-12-2025 03:51
From: Anonymous
Subject: Common cause of MAC pause frames?
This message was posted by a user wishing to remain anonymous
i may mistake but usually it is problem with physical layer of connection for example poor quality of cables - do you checked it ?
second thing i can imagine, maybe it (pause frames and drops) is caused by diferent speed of uplink and client port ?
Original Message:
Sent: 08-11-2025 11:53
From: JOHN WILLIAMSON
Subject: Common cause of MAC pause frames?
No docking stations in use.
Their reported symptom is anything from slowness to noticeable pauses in getting web traffic. They are on Ethernet using a direct cable or a USB to Ethernet adapter. The only thing I have found by checking their interfaces on the switches is pause frames and drops.
John
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JOHN WILLIAMSON
Original Message:
Sent: 08-11-2025 11:37
From: CHRIS ROBERTS
Subject: Common cause of MAC pause frames?
Are these users connecting through a docking station? I'm curious because we had a similar situation that ended up being a firmware bug in a particular docking station.
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CHRIS ROBERTS