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9 votes
Accepted

Is QoS an issue for VOIP calls over the Internet? If not, why not?

VoIP over the public Internet can be a problem, but it usually works good enough, most of the time, although there can be times where it sucks. Most ISPs have extra cost features where they will honor ...
Ron Maupin's user avatar
  • 100k
8 votes

Is QoS an issue for VOIP calls over the Internet? If not, why not?

I'm trying to decide whether I should buy SIP trunks from my ISP or a 3rd-party. and... Is QoS an issue for VOIP calls over the Internet? Short answer: End-to-end QoS is NOT offered on the public ...
Mike Pennington's user avatar
7 votes
Accepted

Is TCP slow start supposed to be enabled for VoIP SIP?

Should TCP slow start be used with SIP-over-TCP? SIP does not transfer large data with TCP. SIP is only used for signaling, the transport of the actual data (voice, video, ...) is done with RTP and ...
Steffen Ullrich's user avatar
4 votes
Accepted

SIP alg on juniper SRX100H2

First, ALGs are technically independent entities. If we are looking at JUST the ALG, it cares only about the SIP signaling packets, not which ports are used. You define the ports by application ...
Jordan Head's user avatar
  • 7,144
2 votes

Forward single DID number to sip trunk

I have a solution working with a Cisco 2800 acting as a Session Border Controller (CUBE) in front of an Asterisk box. The inbound patterns and outbound patterns don't overlap (for me) so its a matter ...
Mike Tubby's user avatar
1 vote

Cisco CP-7841 IP Phone backlight settings not working

Hmm, as soon as I posted this question, I noticed the similarities between the "display" settings and the ones applied on the phone - it seems that the "backlight" settings do ...
ifoindecks's user avatar
1 vote
Accepted

Are SIP numbers provided by the SIP Trunk provider?

I'm pretty sure this kind of question is off topic for this site since it deals with application layer protocols, I think. However, the answer is very simple. Each SIP service provider will have its ...
FrameHowitzer's user avatar
1 vote

Replacing IP address of connections from AWS towards SIP

It looks as though your network is already organised as a VPN, with some of it in location A (office) and some in B (AWS), and there's already NAT at the exit to the SIP provider's equipment. You ...
jonathanjo's user avatar
  • 16.3k
1 vote
Accepted

HP MSR2004 router is not processing udp through nat

It turns out that sip never was the problem. The ip phones (Snom D710) send dns requests to determine if there's a SRV record for sip for that domain. The router discarded the dns requests instead of ...
Daniel Becker's user avatar
1 vote
Accepted

Cisco 7960 SIP phone background image issues

Okay, so it was all down to bmp encoding. When exporting (in GIMP) with these settings, it does work all okay. Sorry for wasting your time :-)
sDoky's user avatar
  • 151
1 vote
Accepted

Cisco ASA SIP/RTP inspection question

Assuming that your VOIP phone is on remote site and you are connected to firewall through VPN(IKEv1 or IKEv2) connection. Your end terminal is able to reach SIP server on some port 5060,5061 or any ...
Vikash Srivastava's user avatar
1 vote

How can I spoof a UK caller ID from the US?

It depends on your PSTN provider. Some will allow you to put anything in the 'calling number' parameter during call setup. Usually though, they will filter out spam. However, you might be able to ...
Ronnie Royston's user avatar
1 vote
Accepted

VoIP Provider and Phone Number Routing Questions

DIDs are assigned by the telcos which own them. A VoIP provider buys a block of DIDs from the telcos it uses where its VoIP network interfaces with the POTS network. Your cell call travels from the ...
Ron Maupin's user avatar
  • 100k
1 vote

Convert encrypted SRTP to RTP for private network

SIP (Session Initiation Protocol) is used to create the session. Basically it prepares the ground for Alice and Bob to communicate directly with each other via whavever protocol they choose (in this ...
Jaroslav Hlaváč's user avatar

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