SFP module yang mana?

Belajar dari website Cisco
http://www.cisco.com/en/US/docs/interfaces_modules/transceiver_modules/installation/note/78_15160.html

Dari situ gw lihat:
- We can use any combination of SFP transceiver modules that our Cisco device supports. 
- The only restrictions are that each port must match the wavelength specifications on the other end of the cable and that the cable must not exceed the stipulated cable length for reliable communications. 
-  We must use only Cisco SFP transceiver modules on your Cisco device

Jadi:
1. Wavelength-nya harus sama
2. cable length-nya tidak melebihi persyaratan module SFP mu
3. tipe fibernya harus sama (kedua switch sama-sama SMF atau sama-sama MMF)

Gimana cara ngelist SFP kamu?
Product Number: GLC-ZX-SM
Connector type: LC
Fiber type: SMF
Wavelength: 1550-nm 
Order this 2 units mammm...

Apa hubungan wavelength dengan panjang kabel?