Thanks. What "all the ethernet control frame juju" might you be
referring to? I don't recall Ethernet, in and of itself, just sending
stuff back and forth. Does anyone know if this FEC stuff I see
concurring is actually contained in Ethernet Frames? If so, please send
a link to show the ethernet frame structure as it pertains to this 400g
fec stuff. If so, I'd really like to know the header format, etc.
-Aaron
On 4/18/2024 1:17 PM, Tom Beecher wrote:
FEC is occurring at the PHY , below the PCS.
Even if you're not sending any traffic, all the ethernet control frame
juju is still going back and forth, which FEC may have to correct.
I *think* (but not 100% sure) that for anything that by spec requires
FEC, there is a default RS-FEC type that will be used, which *may* be
able to be changed by the device. Could be fixed though, I honestly
cannot remember.
On Thu, Apr 18, 2024 at 1:35 PM Aaron Gould <aar...@gvtc.com> wrote:
Not to belabor this, but so interesting... I need a FEC-for-Dummies or
FEC-for-IP/Ethernet-Engineers...
Shown below, my 400g interface with NO config at all... Interface has no
traffic at all, no packets at all.... BUT, lots of FEC hits. Interesting this
FEC-thing. I'd love to have a fiber splitter and see if wireshark could read
it and show me what FEC looks like...but something tells me i would need a 400g
sniffer to read it, lol
It's like FEC (fec119 in this case) is this automatic thing running between
interfaces (hardware i guess), with no protocols and nothing needed at all in
order to function.
-Aaron
{master}
me@mx960> show configuration interfaces et-7/1/4 | display set
{master}
me@mx960>
{master}
me@mx960> clear interfaces statistics et-7/1/4
{master}
me@mx960> show interfaces et-7/1/4 | grep packet
Input packets : 0
Output packets: 0
{master}
me@mx960> show interfaces et-7/1/4 | grep "put rate"
Input rate : 0 bps (0 pps)
Output rate : 0 bps (0 pps)
{master}
me@mx960> show interfaces et-7/1/4 | grep rror
Link-level type: Ethernet, MTU: 1514, MRU: 1522, Speed: 400Gbps, BPDU
Error: None, Loop Detect PDU Error: None, Loopback: Disabled, Source filtering:
Disabled,
Bit errors 0
Errored blocks 0
Ethernet FEC statistics Errors
FEC Corrected Errors 28209
FEC Uncorrected Errors 0
FEC Corrected Errors Rate 2347
FEC Uncorrected Errors Rate 0
{master}
me@mx960> show interfaces et-7/1/4 | grep packet
Input packets : 0
Output packets: 0
{master}
me@mx960> show interfaces et-7/1/4 | grep "put rate"
Input rate : 0 bps (0 pps)
Output rate : 0 bps (0 pps)
{master}
me@mx960> show interfaces et-7/1/4 | grep rror
Link-level type: Ethernet, MTU: 1514, MRU: 1522, Speed: 400Gbps, BPDU
Error: None, Loop Detect PDU Error: None, Loopback: Disabled, Source filtering:
Disabled,
Bit errors 0
Errored blocks 0
Ethernet FEC statistics Errors
FEC Corrected Errors 45153
FEC Uncorrected Errors 0
FEC Corrected Errors Rate 29
FEC Uncorrected Errors Rate 0
{master}
me@mx960> show interfaces et-7/1/4 | grep packet
Input packets : 0
Output packets: 0
{master}
me@mx960> show interfaces et-7/1/4 | grep "put rate"
Input rate : 0 bps (0 pps)
Output rate : 0 bps (0 pps)
{master}
me@mx960> show interfaces et-7/1/4 | grep rror
Link-level type: Ethernet, MTU: 1514, MRU: 1522, Speed: 400Gbps, BPDU
Error: None, Loop Detect PDU Error: None, Loopback: Disabled, Source filtering:
Disabled,
Bit errors 0
Errored blocks 0
Ethernet FEC statistics Errors
FEC Corrected Errors 57339
FEC Uncorrected Errors 0
FEC Corrected Errors Rate 2378
FEC Uncorrected Errors Rate 0
{master}
me@mx960>
On 4/18/2024 7:13 AM, Mark Tinka wrote:
On 4/17/24 23:24, Aaron Gould wrote:
Well JTAC just said that it seems ok, and that 400g is going to
show 4x more than 100g "This is due to having to synchronize
much more to support higher data."
We've seen the same between Juniper and Arista boxes in the same
rack running at 100G, despite cleaning fibres, swapping optics,
moving ports, moving line cards, e.t.c. TAC said it's a
non-issue, and to be expected, and shared the same KB's.
It's a bit disconcerting when you plot the data on your NMS, but
it's not material.
Mark.
--
-Aaron
--
-Aaron
