It's not an issue of bandwidth unless you are talking peer to peer with some client that supports more advanced CODECs. If you call touches PSTN, 99% of the time you are going to use G.711. If your provider users compression your most likely using G.729 and that has a MOS of 3.8 best case.
Ah, yes the quality issue. It drives me crazy that when VoIP providers (yes, as Co-Founder of BroadVoice I was one of them) try to build services the benchmark is PSTN. They use CODECs such as G.711 and G.729 that are almost as old as I am. Believe it or not, DSP power has increased in the last 20 years, Next gen CODECs such as SPEEX can deliver great quality at low bit rates and was designed for packet networks.
One other big issue is that PSTN is only about 4 kHz of bandwidth, when you take the guardbands out it is more like 400 - 3600 kHz. SPEEX, AMR-WB and others support 16 or even 32 kHz of voice bandwidth. The problme is a chicken and egg issue. CPE guys don't want to support it because there is nothing to terminate to. ALl the major VoIP guys use people like Global Crossing, BroadWing, XO, for SIP origination/termination and they use SONUS or other TGs that only G.711 or a few other CODECs.
The real solution is for VoIP providers to support transcoding at the edge. That way you can use next gen CODECs on the last mile and then hand of G.711 to orig/term providers.
There is a standard on how to encrypt voip already called SRTP, the problme is there is still a lot of debate on how to deal with the key exchange. MIKEY is the latest path, but most CPE vendors see it as overkill and to complex. SNOM and a few others have went with SDP Descriptions, a lightweight method, but requires TLS for signaling. Then you have guys like Sipura/Cisco who come up with a 100% propritary way of doing things that only will work with their devices.
Anyone know how this is done? I can understand how to fake your cid number, but how can you fake CNAM? If I faked my number to a real friends number the terminationg switch would do a CNAM dip and display his number. How could I change the text of the name?
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It's not an issue of bandwidth unless you are talking peer to peer with some client that supports more advanced CODECs. If you call touches PSTN, 99% of the time you are going to use G.711. If your provider users compression your most likely using G.729 and that has a MOS of 3.8 best case.
Ah, yes the quality issue. It drives me crazy that when VoIP providers (yes, as Co-Founder of BroadVoice I was one of them) try to build services the benchmark is PSTN. They use CODECs such as G.711 and G.729 that are almost as old as I am. Believe it or not, DSP power has increased in the last 20 years, Next gen CODECs such as SPEEX can deliver great quality at low bit rates and was designed for packet networks. One other big issue is that PSTN is only about 4 kHz of bandwidth, when you take the guardbands out it is more like 400 - 3600 kHz. SPEEX, AMR-WB and others support 16 or even 32 kHz of voice bandwidth. The problme is a chicken and egg issue. CPE guys don't want to support it because there is nothing to terminate to. ALl the major VoIP guys use people like Global Crossing, BroadWing, XO, for SIP origination/termination and they use SONUS or other TGs that only G.711 or a few other CODECs. The real solution is for VoIP providers to support transcoding at the edge. That way you can use next gen CODECs on the last mile and then hand of G.711 to orig/term providers.
There is a standard on how to encrypt voip already called SRTP, the problme is there is still a lot of debate on how to deal with the key exchange. MIKEY is the latest path, but most CPE vendors see it as overkill and to complex. SNOM and a few others have went with SDP Descriptions, a lightweight method, but requires TLS for signaling. Then you have guys like Sipura/Cisco who come up with a 100% propritary way of doing things that only will work with their devices.
Anyone know how this is done? I can understand how to fake your cid number, but how can you fake CNAM? If I faked my number to a real friends number the terminationg switch would do a CNAM dip and display his number. How could I change the text of the name?
64.93.90.35 Port State Service 80/tcp open http 111/tcp open sunrpc 1030/tcp open iad1 68/udp open bootpc 111/udp open sunrpc