PHY to PHY Autonegotiation

asked 2018-09-17 19:55:06 +0000

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I am testing a PHY. I am hooking a PHY from a switch to my PHY under test not hooked up to any MAC. I want to take the recv data and loop it back to the xmit data of the PHY via an FPGA. So whatever comes in, comes back to the sender. I would like to know if Wireshark will capture that data. I have tried and it seems not to display anything. I see data on the xmit data port of the PHY and its enable but cant tell if its being sent out. Is there a raw data mode..thanks

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not that i know of. you would need a cable layer tester like a fluke onetouch

thetechfirm gravatar imagethetechfirm ( 2018-09-17 22:52:05 +0000 )edit

So you're looking at RGMII or SGMII from the PHY (PCS sublayer)? Your question title speaks of autoneg, which takes place in the PHY and will only show as link status on the PHY, so you won't see that on the *MII data interface. In the question text you question if the looped data is being send out. That would then be visible on the wire, so where are you looking? Apart from that. Wireshark has a multitude of datalink types it can capture from, but for Ethernet the lowest is on the MAC layer, below that requires transmission test equipment.

Jaap gravatar imageJaap ( 2018-09-18 11:11:16 +0000 )edit