native is generated by the switch. and you must have ample power supply in the switch to support poe. 1,2 and 3,6
injected is where there is another device between the switch and patch panel. this puts out the 48v required to power an WAP or POE phone. 7,8
or you could use power bricks.
there are not too many advantages or disadvantages. someone correct me if Im wrong.
if you have older switches you dont wish to upgrade you can use an injector. they come in singles, 48, 24. like another switch and takes up more room in your IDF. as weell as more Patch cables.
if your purchasing new equipmenmt and implementing VoIP then most likely you would want to go with POE switches. as these will take up less space.
Cisco 7971G-GE
Cisco 7975G-GE
Cisco 7965G-GE and 7945G-GE
Cisco 7962G-GE and 7942G-GE
Cisco 7961G-GE and 7941G-GE
Cisco 7970g-ge
more than 3 models support gigabit.
i've only seen the 7961g which means "Global" so there icons on the buttons not english text. never seen a "GE"