Asterisk and openSER - where is a diffrent

Hi. In that topic I read it’s better to use SIP Proxy like SER if I will be VOIP ISP and don’t use Asterisk for that. I don’t know why ? Where is a diffrent. If I will terminate all connections to big provider like Betamax i need Asterisk or no ? Please explain me where is a diffrent and what is better? Does openSER have the same options like Asterisk (3 way calling, MoH, etc). If I’d like to be a VOIP provider I need just only servers with OpenSER ? May I put voicemail, IVR, billing, etc on OpenSER and transfer all calls to bigger VOIP provider (terminating) ?. My friend said is something like that: I have 2 servers - on one server I install OpenSER and on second server I install Asterisk. And OpenSER is registar and proxy server and transfer call via patch to Asterisk server and Asterisk transfer call to bigger VOIP provider? is that true ? Please tell me how it’s works ? What I need to use - just only OpenSER, Asterisk or OpenSER and Asterisk together. Please for help. Thank’s. Bye

SER is a proxy and does not have PBX features such as music on hold, voicemail, ivr, etc.

Does Asterisk contain all the features that SER contains? For example if one was having difficulties connecting various sip devices behind a firewall to an asterisk system, would SER make these connections easier?

Asterisk does have a NAT setting which usually works great.

OK. So If I’d like to set up high voip services that will be great to set Asterisk cluster using OpenSER at front of platform and Asterisk servers at inside ? So my platfrom will have one IP address for users but everything connections will be goes to Asterisk servers (also with loadbalancing) ? With option is better - OpenSER with Asterisk inside or Asterisk DUNDI ? with one is better ?. How is with billing with OpenSER - i have to install billing system on openSER or on Asterisk servers inside ? But how it’s works ? . Please for reply. Thank’s. CU