Voice over Internet Protocol (Voice over IP, VoIP) is one of a family of internet technologies, communication protocols, and transmission technologies for delivery of voice communications and multimedia sessions over Internet Protocol (IP) networks, such as the Internet.

learn more… | top users | synonyms

17
votes
6answers
58k views

Finding cause of TCP retransmission within a LAN

Hello denizens of Server Fault I have an irritating problem with a LAN of about 100 computers, 2 Windows domain servers, and 12 VoIP phones. Since their installation around a year ago, every week or ...
16
votes
5answers
389 views

What alternatives do I have for telephony if my LEC says the Central Office has an issue?

In our New York office we've been waiting for almost a month for Verizon Business to repair a problem at our local CO. They keep saying that the damage from Hurricane Sandy was so extensive that they ...
15
votes
2answers
2k views

Can anybody explain why to use Asterisk PBX rather than standard PBX from Matrix or Siemens [closed]

Can anybody explain why open-source Asterisk is favourable in comparison with a traditional PBX system from a vendor such as NEC/Syntel/Matrix or Siemens.
11
votes
2answers
4k views

Can you please explain the difference between PBX and soft switch in less technical terms?

Asterisk is an open source PBX and FreeSWITCH is an open source soft switch. Source: http://www.freeswitch.org/node/117 Can you please explain the difference between PBX and soft switch in less ...
11
votes
2answers
866 views

Asterisk for Small Business - Where to Start?

I have been in IT for a long time now doing software development and some system/server administration, but all mostly software-related services. I would like to help set up a small business (~50 ...
10
votes
3answers
512 views

Architecting network with 10 Mbps half duplex phone system

Current Configuration The diagram below shows our current network architecture. All connections are running at 100 Mbps full duplex with the exception of the TalkSwitch phone systems which run at 10 ...
8
votes
4answers
3k views

Cooling requirements for POE switches?

Is there any difference between POE switches and normal switches when budgeting for cooling capacity for a network closet? Normally, when I'm thinking about cooling; I can look at the power draw of a ...
7
votes
4answers
1k views

Asterisk running on VMware

Does anybody have experience or running Asterisk on VMware(?) - specifically the latest ESX...? I've got a proof of concept working but am reticent to roll it out without a bit more reassurance! I ...
7
votes
3answers
926 views

What are some potential uses of Asterisk (PBX) for a “power user”

So I read a lot of good things about Asterisk. I am not however looking to run a call center or small business setup. I am still interested what potential uses it has for me as a "power user" and ...
7
votes
5answers
848 views

Cross-platform VOIP + IM client and Linux server

Right now, a group of our employees is using Skype for group chats and conference calls. They're not using telephone numbers, just Skype user accounts. I'd like to set up a server that will provide ...
6
votes
4answers
4k views

Is it possible or advisable to virtualize a PBX system? How would one go about this?

I'm totally new to the world of VoIP and we are looking to move from our current provider to a solution we host ourselves, mainly because the current service is so unreliable. Unfortunately I know ...
6
votes
3answers
13k views

How many resources does a mumble server need?

Given a default instance of Ubuntu Server LTS, how many additional resources are needed to run a Mumble server ("murmor") for say 10 connected users? I'm curious about: CPU consumption RAM working ...
6
votes
4answers
909 views

VoIP PBX, custom build or appliance?

I'm looking for advices regarding VoIP products. I need to build an in-house VoIP PBX for one of my company's office, and while I'm fairly sure we will go with Asterisk (still leaving the door open to ...
5
votes
2answers
1k views

How should I structure a VoIP phone system?

I'm going to be setting up VoIP for a small business that is expected to grow rapidly. I don't really understand much about VoIP other than it's a telephone system that works over a regular network (...
5
votes
2answers
632 views

Is it possible for Wireshark to drop packets purposely?

I would like to test something like VoIP. I would like to test with some "artificial packet loss". Is Wireshark able to do this? Or is there any good solutions?
5
votes
2answers
112 views

Using an extension to block a caller

I have a couple of SIP phones and use callcentric. I get a lot of junk calls. I'd like to implement the following feature and would like some suggestions on how to do this: Once I get a junk call, I ...
5
votes
3answers
174 views

VoIP phone recommendation with good speakerphone under $300 [closed]

I'm looking for about a dozen VoIP phones for a small office. Criteria: Not Polycom (terrible support) Under $300 USD Good speakerphone quality Any brands/models you would recommend based on your ...
5
votes
2answers
1k views

Ways to monitor SIP termination on an asterisk server

I have a nagios setup which ensures that SIP is responsive on my Asterisk server, that's straight forward. My question is, what kind of possibilities are there that the Asterisk server can actually ...
5
votes
2answers
110 views

Trans-atlantic VOIP

We're a Canadian business on the east coast and will soon be opening up a new call centre in Australia. This new call centre will be handling our graveyard shift and will be overlapping with the ...
4
votes
6answers
1k views

Cisco vs Everything else

A huge debate raged when we were setting up a new phone system. The guys doing the install did not believe in paying high prices for Cisco gear when they could do the same things with lower priced ...
4
votes
4answers
1k views

What does “non-IP” originated traffic mean in a TOS?

I am looking at VoIP providers and many of them have a part of their TOS that says they don't allow "non-IP originated traffic." Excerpt from TOS: You shall only send to [DELETED COMPANY NAME] ...
4
votes
6answers
2k views

What bandwidth would be required for 55 VOIP Lines And what type of Internet connection

In a call centre environment, what bandwidth would be required for 55 lines? This would be on SIP protocol, would we be best to use G729 codec as i know that our sip provider supports this? What type ...
4
votes
1answer
858 views

High availability Asterisk options?

We currently run FreePBX on a single node. I'd like to have a cluster of asterisk instances for sharing the load, but mainly for failover. I'm curious how other people have solved this problem. ...
4
votes
8answers
15k views

How can I simulate a modem over a VOIP connection?

I have a hardware device I need a server to dial into at regular intervals. The problem is I no longer have a POTS line or a modem in any of development computers, and all my production servers are ...
4
votes
1answer
129 views

Ping time variation correlates with IP phones not working

We have an IP Phone system (most models are snom 320). Today someone's phone has decided to stop working. It has an IP address assigned to it by DHCP, and I can sometimes go to it's IP address to view ...
4
votes
2answers
3k views

What would cause a PBX or SIP phone to not register on the network when using Netgear Switches?

We have 3 different types of switches in our network. All of our IP Phones are running on HP 2520-24 PoE switches. Our primary backbone is "supposed to be" running on Netgear GS748T switches. ...
4
votes
3answers
9k views

Bringing people into an Asterisk conference call

I'm using Asterisk 1.4 and am trying to work out a way to bring people into a conference call. In the ideal scenario two people would be talking and one of them would push some keys, then a phone ...
4
votes
1answer
22 views

Redirect Call Back Out To PSTN

I'm wondering if it's possible on a VoIP system (specifically Asterisk) over SIP trunks to redirect a call back out to the PSTN to no longer be routed through the PBX. What I'd like to do is see ...
4
votes
0answers
269 views

RTP analysis - Discerning ptime (packetization time) for a given VoIP packet capture

I would like some help on the subject of an automated way of discerning the average packetization time (ptime) of a VoIP call's packet capture. The reason I am not depending on the value in the SDP ...
3
votes
5answers
806 views

What are the best LAN communication systems? [closed]

What are the best messaging and VOIP systems for medium to large corporate networks? What have you found to be the best in your experience and why? It should support: Instant messaging Video and ...
3
votes
4answers
1k views

Using the Built in Switch in IP phones

I'm working on setting up a small business with IP Phones to connect to the Asterisk Server. Now, for simplicity we just ran 2 CAT5e lines to each room, and 1 was hooked to a phone jack, before my ...
3
votes
2answers
1k views

Extremely Poor VOIP Audio Playback Performance During Live Phone Calls with Remote Desktop Services

The setup: Plantronics USB CS50 Headset > USB Port of "Thin Client" (Running Win Pro) > (Wireless) RDP to Remote Desktop Server > Eyebeam Softphone Client > VOIP Server > Caller (cell phone or ...
3
votes
2answers
3k views

DHCP and DNS services configuration for VOIP system, windows domain, etc

My company has numerous physical offices (for purposes of this discussion, 15 buildings). Some of them are well-connected to our primary data center via fiber. Others will be connected to the data ...
3
votes
2answers
2k views

How can I disable the audible MWI on Polycom phones?

By default, when a Polycom VoIP phone has a voicemail message waiting, it both lights the MWI light, and plays a sound every several minutes. I've never met a more self-important feature in a phone, ...
3
votes
2answers
349 views

Using Windows Server 2003's DHCP service to give different router to specific hosts

I have a very small network of maybe two dozen machines, to which I've just added 7 IP telephones, talking to a Mitel controller on another site. I also have 2 ADSL links, using consumer ADSL routers. ...
3
votes
1answer
1k views

asterisk/freeswitch in nat/no-nat setup

my current setup - i use bunch of sip hard-phones around few offices. all devices have two sip accounts configured - one on internal sip proxy [for calls between the branches], another - at 3rd party ...
3
votes
3answers
667 views

Any good phone system on a Windows Environment?

I am looking for a phone system that integrate well with an (almost) 100% Microsoft environment. I would like something that can integrate with Exchange and Active Directory (in-phone searching/...
3
votes
1answer
187 views

Asterisk: Got 2 PSTN numbers, want to go IP. Need a card

I'm familiar with Networking, VoIP, Asterisk and Linux... but I've never deployed a VoIP with PSTN. I've got one week to deploy VoIP + 2 PSTN numbers, I don't mind reading like crazy but I would like ...
3
votes
1answer
8k views

What is mumbles average monthly bandwidth usage?

I am wondering how much bandwidth does a Mumble server use in the span on a month. I have a dedicated Linux server with 10,000GB bandwidth/month. In their FAQ they have this formula and information. ...
3
votes
1answer
140 views

Does anyone know a good Website comparing all the PBX/IP telephone solutions?

I'm looking for a good website dressing a comparative analysis of the most popular telephony solutions resellers (Cisco, Avaya, Siemens, Microsoft, etc...). I already found a very nice work comparing ...
3
votes
3answers
263 views

Cheap VoIP Phone Recommendation [closed]

I'm looking for an inexpensive corded VoIP phone for my home office that supports SIP. I've been using an old Cisco 7905G with SIP firmware but I'm concerned about security considering that it's ...
3
votes
1answer
4k views

QoS settings for Wi-Fi calling on pfSense firewall/gateway?

The new version of iOS 8 as well as Android supports Wi-Fi Calling with multiple cellular providers including T-Mobile in the US. I am currently running pfSense as the primary Internet gateway for ...
3
votes
2answers
4k views

Setting up a SIP NAT proxy

We currently run a VoIP server using an upstream providers SIP proxy for our clients who are behind NAT. We now have the problem that we re ending the relationship with the upstream provider, and will ...
3
votes
2answers
171 views

Looking for ballpark pricing on an affordable a Cisco VOIP solution for our office [closed]

We have about 8 incoming PSTN lines that are currently on an old and antiquated Nortel Meridian ICS system. This system has been giving us some grief. We're looking for a new VOIP solution. I've been ...
3
votes
4answers
7k views

Prioritise VOIP traffic over a VPN link

We have recently opened a branch office for developers to work out of. The guys there all have Aastra VoIP 'hard' phones on their desks. The main office and branch offices are linked together via a ...
3
votes
0answers
154 views

Hacker bypassing iptables

(moved from SO) I have iptables protecting a sip server. It blocks all IPs except ones I specifically opened, and it seems to work for almost everyone. I have tested from lots of ip addresses that ...
3
votes
4answers
17k views

How to stop registration attempts on Asterisk

The main question: My Asterisk logs are littered with messages like these: [2012-05-29 15:53:49] NOTICE[5578] chan_sip.c: Registration from '<sip:912@xx.xx.xx.xx>' failed for '37.75.210.177' - ...
3
votes
2answers
387 views

Dumping configuration from a Sipura 8800

Is there any way to retrieve the configuration from a Cisco Sipura 8800? And no, I'm not talking about nonsense like saving the HTML pages. I'm talking about saving the proper .xml configurations so ...
2
votes
5answers
373 views

Intercom over IP?

This is an odd request, but I'm hoping some of you have had to field it before: We have an office in New York and remote employees in Oregon and Florida. Communication is extremely important to us, ...
2
votes
5answers
325 views

VOIP Power outage strategy

In the past 2 years, we have had 4 instances where we have been without power for a period of 4-6 hours - due to construction crews cutting power lines, car accidents involving downed power lines, etc....