VOIP on Netgear WNR1000

I was facing problem with outgoing calls through my Gigaset A580 IP. Although the incoming calls were fine from both Gizmo5 and Localphone.com, outgoing calls dropped after 20-30 secs! After googling finally found that the problem lies with my Netgear router. The following router settings stopped outgoing calls from dropping out.

• Disabling "SIP ALG" under WAN>NAT Filtering
• Under LAN, choosing RIP version to be RIP_2M
  

Now both my VOIP accounts, localphone.com and Gizmo5, work smoothly.