Alcatel Unleashed

Hi, I'm using 6900 V72, I have traffic entering on port 47 of the switch and leaving from port 41. I'm using simple forwarding, whatever I receive on Port 47 is to be sent to Port 41.
I'm using 25G Uni SFPs and the detected speeds are also 25G. also, I'm not in an overload situation.

I see some strange behavior where if I send anything up to 1 Gbps, I see all traffic passing but If I send more than 1 Gbps, let's 2 Gbps, I see only 1 Gbps passing.

My topology looks like this:
Traffic generator -> OLT -> ONT -> Omniswitch -> Back to Traffic generator.

In short: Let's say I send x number of packets, I receive them on OLT, ONT and port 47 of the switch, but I see only y packets leaving from port 41.
where y is less than x.

Has anyone seen this strange behaviour in the switch? I have already tried rebooting the switch but it doesn't resolve the issue...
I have also tried using completely different ports and Uni SFPs but saw the same issue.

Any help in this regard would be greatly appreciated.

Hi,
never seen this behavior.
You checked with "show inerfaces counters" for both ports? There you see the InOctets and Packets at one port increasing. And at the other the OutOctets etc. Also you see the In/Out Pkt/s for the last 5 sec.
There you see the differences too?
If yes you should open a ticket at ALE.
BR Silvio

Hi Silvio,

Yes, I have checked that indeed, here is the summary:

I sent 1,281,693 frames, each with frame length = 1500 Bytes.
You can see all 1,281,693 frames enter Port 47, but only 523,563 leave Port 41

-> show interfaces 1/1/47 counters
1/1/47 ,
InOctets = 1922539500, OutOctets = 576,
InUcastPkts = 1281693, OutUcastPkts = 0,
InMcastPkts = 0, OutMcastPkts = 9,
InBcastPkts = 0, OutBcastPkts = 0,
InPauseFrames = 0, OutPauseFrames = 0,
InPkts/s = 0, OutPkts/s = 3,
InBits/s = 0, OutBits/s = 1336

-> show interfaces 1/1/41 counters
1/1/41 ,
InOctets = 0, OutOctets = 787442272,
InUcastPkts = 0, OutUcastPkts = 523563,
InMcastPkts = 0, OutMcastPkts = 55,
InBcastPkts = 0, OutBcastPkts = 0,
InPauseFrames = 0, OutPauseFrames = 0,
InPkts/s = 0, OutPkts/s = 1,
InBits/s = 0, OutBits/s = 456



-> show interfaces 1/1/47 accounting
1/1/47:
Rx Undersize = 0, Tx Undersize = 0,
Rx Oversize = 0, Tx Oversize = 0,
Rx Jabber = 0,
Rx/Tx 64 Octets = 9,
Rx/Tx 65 ~ 127 Octets = 0,
Rx/Tx 128 ~ 255 Octets = 0,
Rx/Tx 256 ~ 511 Octets = 0,
Rx/Tx 512 ~ 1023 Octets = 0,
Rx/Tx 1024 ~ 1518 Octets = 1281693,
Rx/Tx 1519 ~ 4095 Octets = 0,
Rx/Tx 4096 ~ MAX Octets = 0

-> show interfaces 1/1/41 accounting
1/1/41:
Rx Undersize = 0, Tx Undersize = 0,
Rx Oversize = 0, Tx Oversize = 0,
Rx Jabber = 0,
Rx/Tx 64 Octets = 57,
Rx/Tx 65 ~ 127 Octets = 0,
Rx/Tx 128 ~ 255 Octets = 0,
Rx/Tx 256 ~ 511 Octets = 0,
Rx/Tx 512 ~ 1023 Octets = 0,
Rx/Tx 1024 ~ 1518 Octets = 523563,
Rx/Tx 1519 ~ 4095 Octets = 0,
Rx/Tx 4096 ~ MAX Octets = 0



-> show interfaces 1/1/47 traffic
Ch/Slot/Port Input packets Input bytes Output packets Output bytes
------------+-----------------+-----------------+-----------------+----------------
1/1/47 1281693 1922539500 6 384

-> show interfaces 1/1/41 traffic
Ch/Slot/Port Input packets Input bytes Output packets Output bytes
------------+-----------------+-----------------+-----------------+----------------
1/1/41 0 0 523603 787441312



^ In this experiment, I sent only Downstream traffic, but it is important to mention that if I send Upstream traffic, I don't see this strange drop in Upstream direction even at much higher throughputs.
I have experimented a lot with sending only DS traffic, sending both US and DS together, sending US first, then sending DS, but no matter what I do, I cannot pass more than 1 Gbps in the Downstream direction.

Have you tested without OLT/OND too?
And what is the output of "InBits/s = xxx, OutBits/s = xxx" during the test stream in both directions? This is the speed for the last 5 sec.
In US you can see there more than 1Gbps? But never in DS? Strange to understand if the same behavior is at other ports too. Thats why I think the OLT/OND must be the reason.... but than the incomming packets should lower at the switch too. Very strange.
Have you tested the same for both direction: f.e. TG-1 -> 41 -> 47 -> TG-2 and TG-1 -> 47 -> 41 -> TG-2
If the same issue is seen always from TG-1 to TG-2 than the switch should not the reason.

And you see it not only in the show-outputs of the switch (maybe there is an monitoring issue) - you see the issue at the traffic generator too?
BR Silvio