Wired Intelligent Edge

Hello,

Are SFP 10G backward compatible with 1G speed ?

One of our customer has some errors on fiber link and suspect it is not compatible with such speed and asks to downgrade speed in the configuration.

Is it possible or should I recommend to swap 10G SFPs with 1G SFPs on this uplink ?

Many thanks

Franck.

AFAIK a SFP+ (read: SFP Plus) Transceiver goes at 10 Gbps Full Duplex, not any lower speed like 1 Gbps (a SFP Transceiver - withouth the Plus suffix - works at 1 Gbps Full Duplex), so you can't down rate a 10 Gbps SFP+ Transceiver's port speed as you would do on a typical RJ45 10/100/1000 Mbps copper port (the SFP/SFP+ Transceiver sets the speed and the Switch slot in which that Transceiver is inserted lets it to communicate with other switched ports, you can't change the Full/Half Duplex Mode or the Speed).

So if you're using a SFP+ Transceivers pair the fiber optical link should be up at 10 Gbps Full Duplex (provided that the Fiber Optic link is clean OK).

The only way to go at 1 Gbps Full Duplex is not using a SFP+ Transceiver but using, instead, a SFP one.

Which SFP+ Transceiver(s) and which Switch(es) are you working on exactly (HPE/Aruba SKUs would help)?

Hi,

Do you mean all Aruba switches or WLC that support SFP+, can use either SFP or SFP+ transceiver

tq

We have an Aruba 2930, would that be able to use a 1G SFP module?

Hello,

Yes, according to ArubaOS-Switch Transceiver Guide (link below - page 28), 1G SFP module (J4858C) is supported by Aruba 2930 Switches.

https://support.hpe.com/hpsc/doc/public/display?docId=c05115518&mkt_tok=eyJpIjoiTXpRd1pETXpNakF3Wm1ReCIsInQiOiJ4NStTc0lEU3BHa3duQVA5dkY2dkprRUlTeGZlVnJwMkpWYWlFMW5yVjFXc0NzT2xBUmVQbHJpdXVEOVBiaU84UVwvUmIxd3FXQ1lsVHg5bHUxS1oyaXhkS0NVdkV4WFcwdjdQNUlUNVdLNm89In0%3D

Thank You,

Greetings!

There is also a newer revision of the same transceiver (J4858D) which is also compatible, and listed in a just-published revision of the same guide.

Hello Parnassus,

My company plans on up-linking an offsite server via fiber to one of our core Arubas. However our Server has no fiber ports and we'll be using a startech converter.

So my question: an Aruba 2930F 24G 4SFP+ Switch (JL253A) can take a 1GB SFP tranceiver running 1GB MM fiber to a Startech convert and connect to that server via Ethernet and have communication?

Thank you in advance, your answers are always insightful. 

As long as it is a supported 1G transceiver on the switch side of the connection, it should work normally. 

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@ITGUYMC wrote: an Aruba 2930F 24G 4SFP+ Switch (JL253A) can take a 1GB SFP tranceiver running 1GB MM fiber to a Startech convert and connect to that server via Ethernet and have communication?

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Yes. I also quote Matthew. Provided that the SFP Transceiver used on the Aruba 2930F side is a supported one (like the original Aruba J4858D SFP LC SR Short Range [*] Transceiver) you're OK.

On the other end you should use a Media Converter, probably one of these equipped with a proper supported SFP Transceiver (not necessarily an HP branded/compatible one but clearly with the same technical characteristics of the one used on the Aruba 2930F side...so one that works at 850 nm with LC connector).

[*] fiber optic run should be below 500 meters.