FireBrick SFP: Difference between revisions

The FireBrick FB2900 has 4 copper ports and 1 SFP port. The SFP port allows flexible connection to other devices - e.g. a 5th copper port, fibre or DACs, and even VDSL modem (ymmv).

==TL;DR==

Regarding the SFPs, the short version is almost any copper SFP should

work for the FB2900, but there are a few silly types that don't. Generic MSA encoded SFPs should be fine.

=More Information=

The longer version for a bit more context:

Most SFPs have a little ROM chip inside them with make/model etc., and

most vendors use this to lock you into their own SFPs, i.e. Cisco switches

paired up with specific Cisco SFPs on an allow list. They probably do this

for a reason, but it's really annoying, especially when you think you've

got an SFP, plug it in, only to find the switch rejects it as it's not

the "right" one.

The Firebrick 2900 is a bit more pleasant and actually doesn't really

care what's in the EEPROM as such, so you are free to use /almost/ any

SFP, provided the electrical connections are as expected.

For Copper SFPs, the FireBrick 2900 needs the "NO RX_LOS" hardware type,

which a majority are. This is down to how the SFP was wired with respect

to the LOS Pin. This is thankfully the most common type.

We've tested Flexoptix T.C12.02.A (Generic SFP flashed to have

it's EEPROM looking like a Cisco GLC-T) with the FB2900, but anything

that the T.C12.02.A can be flashed to should just work as they are all

electrically the same.

(See

https://www.flexoptix.net/en/sfp-copper-transceiver-1-gigabit-cat-5-rj-45-100m-autoneg-serdes.html?co3097=85155

for the various vendors and models it can do)

===RX_LOS Types Don't work===

Copper SFPs of the "RX_LOS" type don't work with the FB2900, such as the

Mikrotik S-RJ01 we tested. The Flexoptix T.C12.02 (note no .A appended)

and it's flashable derivatives will also be in this class. The RX_LOS

type are a bit of a daft class and I've never really got my head around

just why Flexoptix T.C12.02.A exist. Thankfully they're less common.

===Copper SFPs===

One final thing to bear in mind with a Copper SFP, is that they can only

negotiate a link at 1G, so the device plugging into them MUST support

Gigabit Ethernet. 10M and 100M are unsupported by the standard and will

not get you a link.

===VDSL SFPs===

We have tried VDSL SFPs, and they do work. There are a few caveats - they seem to run hot and may provide a less stable connection (i.e. sync drops). Not recommended.

=== 10G SFP+s===

We don't recommend trying to use a SFP+ DAC or SFP+ fibre module in the FB2900. Whilst running 1G over a 10G capable SFP+ device sometimes works, there is no guarantee, and we suggest sticking to 1G.

===FB6000===

There are no SFP ports on the FB6000 model.

===Port Status===

The FireBrick does give you some information about the SFP:

[[File:FB2900-port-status.png|frame|Port Status]]

[[Category:FireBrick]]