Folks, imagine I have 6509 and 3750's currently with GLC-SX-MM SFP's.
Initially I was planning to deploy Data Center-6509>--1000ft--[ MDF-6509-]---400 ft IDF's.
Then I thought about eliminating the switches on MDF and save money.
Given the distances to some IDF's will be more than 500m, I would deploy Single Mode fiber all the way from the Data Center to IDF's.
a) If I deploy Single Mode fiber, in addition to adjust the SFPs to long-haul ones, do I need to change anything on my core 6509 and IDF 3750's to handle the single mode fiber?
Single mode is predominant in carrier facilites and DWDM. All our OC-x and DWDM based services are SM. Our experience is that is is better at distances, and higher bandwidths.
in my customer networks shorter links use MM fibers and longer links use SM fibers.
In your case saving the money of the devices you don't need to deploy is a good idea.
>> I was told that single mode deployment it is hard to test
From a mechanical point of view SM fiber cables are not weaker then MM fiber cables.
May be optical TDR instruments for SM fibers are more expensive.
But they exist:
>> n IDF only at 100 meters but using Single Mode. Is that a problem?
No, I have used also 3 meters SM fibers with no problems in lab setups.
Sometimes you may need an 5dB or 10 dB attenuators with ZX GBICs that are for very long reach not with LH.
The useful advice is to use two SFPs of the same brand at the two ends of the link.
>> Tell me, why people are no simply doing Single Mode this days instead of MM?
It is probably an habit.
Hope to help