Hi,
You can use something like this:
interface POS5/1/0
ip address 146.x.x.25 255.255.255.252
ip pim sparse-dense-mode
encapsulation ppp
no keepalive
clock source internal
end
interface POS1/0
description OC3 to MGOR1-POS5/1/0
ip address 146.x.x.26 255.255.255.252
ip pim sparse-dense-mode
encapsulation ppp
no keepalive
end
On the following link you'll find clocking recommendations for your POS interfaces:
http://www.cisco.com/warp/customer/127/POS/posclocking_16181.html
Hope it helps!
Regards,
Juan