[j-nsp] 100Base-LX10 and MX80

[Richard A Steenbergen]

On Wed, Feb 29, 2012 at 02:35:09PM +0100, ??ukasz Dudzi??ski wrote:
> 
> I did it already. The topic you have mentioned does not cover the 
> essence of my question. I've asked for that specific SFP 
> (100Base-LX10), not for using third party optics at all. The problem 
> is that I don't know if it is possible to use 100Base-LX10 optics in 
> MX80, because Juniper documentation does not mention about 
> 100Base-LX10 SFP. There is a note regarding 100Base-FX (FE on MMF), 
> but no 100Base-LX10 (FE on SMF).

Generally speaking, the answer is "unless the pluggable requires some 
special handling from the router above and beyond what is considered 
'normal' relative to the other pluggables, it WILL work regardless of 
whether or not it is officially supported".

So far the only two examples I've found of the above are copper vs fiber 
(copper sometimes requires special handling to do things like detect 
link state properly), and 100 vs 1000. The LX10 part is irrelevent, if 
it was a 1000BASE optic you could throw in 1km or 100km and the router 
wouldn't know the difference, but you're on shaky ground with the 100 
support. You also run into questions about whether 100 is even supported 
at all, since there are different ways to implement the PHY, one with 
10/100/1000 support, and another with 1000-only.

My personal recollection is that MX back in the DPC days only supported 
1000. I could probably go dust off some documentation on the internals 
of the MX80 and tell you whether the PHY for the modular version 
supports 10/100/1000 for the SFPs or not (its a slightly different hw 
layout for modular vs non-modular, obviously the non-modular does 
because its 10/100/1000 copper), but its late and lets be honest I 
really don't care that much. :) I'm sure someone else will do it now 
that I've taunted them though (I can think of at least 5 or 6 usual 
suspects who probably know this off the top of their head :P), so just 
consider the above as generic advice for when this question comes up 
again in the future. :)

-- 
Richard A Steenbergen <ras at e-gerbil.net>       http://www.e-gerbil.net/ras
GPG Key ID: 0xF8B12CBC (7535 7F59 8204 ED1F CC1C 53AF 4C41 5ECA F8B1 2CBC)