[AusNOG] 10GBs

Chris lists at shthead.com
Thu Nov 9 12:08:52 EST 2017


Hi,

On 9/11/2017 7:24 AM, Robert Hudson wrote:
> If you stick with fibre, you also need to make sure that you're running 
> the right type of cable.  Single-mode is for long range or extended 
> range (generally between DCs), multi-mode is for short range (within a 
> server room/data centre).

IMO, I would just stick with single mode everywhere. The advantages of 
doing that far outweigh the benefits:

- No need to stock up on different patch cables
- No need to stock up on different SFP's. If you are in a multi vendor 
environment, it becomes a pain to have one set of SM optics for vendor X 
and Y and then another set of MM optics for vendor X and Y. Multiply 
that for how many vendors you have.
- No question when installing new gear of "do I need SM or MM? what was 
this patched as/what is the existing X-connect? how far is the link 
going and is it slightly over the budget for MM?" and more...
- In future you want to use WDM its easy
- If you decide to go from 10G to 40G or 100G its also easy

Yes the optics for SM are a little bit more expensive but it will most 
likely save you costs in the long run. If you are buying third party 
optics (I have had a lot of success with fs.com) the price difference is 
much lower than vendor ones. Its worked out cheap enough to have a lot 
of spares and not even bother sending any DOA ones back (so far it is 
about 2 per 1000 DOA for me from fs.com) for me. It has also paid for 
itself where WDM has been needed after the fact, no need to rip out any 
of the existing cross connects.

Personally I would also always opt for at least 24 core cross connects 
everywhere at the minimum, even if you think you will only need a few 
cores. It is cheaper and easier to get this done intiially than get 
installers back to do it all over again.

I have also had mixed success with DAC's, personally I am not a fan. I 
have had issues with links between Juniper QFX and MX gear where the DAC 
will work initially, but should that link go down I have had to 
disable/enable the interface on the QFX end to get it to work again. It 
usually works out neater to just use normal fibre patches as they are 
thinner and easier to cable manage. Also had similar issues between 
servers with Intel NIC's (mainly X710) and the QFX's.

Thats my 2c.


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