Our company has two Cisco routers, which are 2600 and 3600. We place one 2600 router in branch office which has 512K VPN connecting to the 3600 router in headquarter. The problem is when data is transferring; the voice quality will become jitter and loss. I use "ping -t" function, usually I got 16 or 32ms reply, which voice is very stable. If there is data transferring, the rate will come up and down from 16ms 280ms or even higher, then the voice will be jitter or even loss. Is there any way we can limit data and voice bandwidth separately to avoid the interferer¡¦s problem? Since we have had only one output of 512k from our DSU/CSU, I assume that bandwidth could be separated through 2600 router. Please help. Thank you for your BIG help!