[syslinux] Doubt in Syslinux with PXE server with boot ISO image

[spiderslack]

HI all,

I set up a PXE server by following the following howto ( 
http://www.tecmint.com/install-pxe-network-boot-server-in-centos-7/ ) is 
working but I noticed him running I need the CD in one repository http 
or nfs.

because it is necessary to have everything in ISO image? it is possible 
to boot an ISO by the network as I do with the CD or DVD?

Regards.