[pptp-server] GRE with cisco IOS IP Plus on version 11.1

[Ismandy Ali]

Hi again guys,
       Is the type of router (IOS) used  is also effect the use of GRE? I have
a short discussion with my friends that he told me there is such possibility
that  the router doesn't accept the type of GRE that ie being used. I am using
router  with version IOS IP Plus on version 11.1

Sounds weird to me, but this question sis to make sure. this is an excerpt
from  ciscom page:
------------
GRE is a tunneling protocol developed by Cisco that can encapsulate a wide
variety of protocol packet types inside IP tunnels, creating a virtual
point-to-point link to Cisco routers at remote points over an IP internetwork.
By connecting multiprotocol subnetworks in a single-protocol backbone
environment, IP tunneling using GRE allows network expansion across a
single-protocol backbone environment. In order to run GRE, the particular
Cisco router must run the IOS with IPSec and version 12.1 onwards.
--------------

But I believe that this is true if I am running IPSEC, but still not sure.
somebody , have any idea?