Questions[voip](server)

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 can't get the CO back in shape. The date keeps slipping and my superiors are getting restless.

VoIP is an option, of course, but they want circuit-switched quality for the calls which one isn't going to get from using an internet VoIP provider. Does anyone have any other ideas on how to get telephony to a building without involving the Local Exchange Carrier?

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 technical terms

Examples illustrating the difference between the two would be highly appreciated.

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 employees) with Asterisk, but I am not very familiar with how the whole T1, data/voice channels, etc work. I have set up a personal Asterisk server (functional), but have not done so with a pipe like a T1 (which sounds more complex than residential cable/DSL).

Are there any resources out there to help me understand what may be needed of me to help set this business up with Asterisk and re-use their existing T1 pipe?

Any help would be greatly appreciated.

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 Mbs half duplex (upper right-hand corner of diagram). The TalkSwitch boxes each provide 8 analog and 8 IP-based phone connections, so we can have a total of 16 analog and 16 IP-based phones.

Note: The four HP ProCurve 2524 managed switches are not configured with separate VLANs.

I'm concerned about the performance impact of having both switches, both TalkSwitch boxes, and the wireless bridge connected to our RV082 VPN router in our HQ.

Proposed Configuration

I'm proposing that we change our configuration as shown below. My thought is that this will limit the RV082 to only seeing internet bound traffic with the exception of providing DHCP to the dynamic clients; however, I wouldn't expect that to be much of a performance impact given that the client lease time is set to 24 hours.

Thoughts? Concerns? Recommendations?

One concern is that in building #2 & #3, the IP-based phones communicate with the TalkSwitch boxes at 10 Mbps half duplex. Will that adversely impact the performance of the rest of the network?

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 so, we notice a VoIP phone resetting itself - occasionally in the middle of a call. Simultaneously there are often signs of temporary loss of connection on computers: freezes in explorer while accessing network shares, errors in our administration software due to loss of connection to the database server.

I have been doing some Wireshark monitoring on the connection between the VoIP PBX and the rest of the network. Wireshark picks up a clump of retransmitted TCP packets at the times when we record phone restarts. The Wireshark log shows about 2 clusters of retransmissions a day ranging from 5 packets to hundreds. Those in each cluster are mainly between the PBX and some set of the VoIP phones, but not always the same set. Often retransmissions at the same time are to phones connected to the same switch, but sometimes retransmissions occur together to phones at opposite ends of the network. There are usually some coincident retransmissions in passing TCP traffic, for example between client machines and the file servers.

The spikes in retransmissions and phone resets do not correlate well with when the network is heavily loaded. They seem to occur slightly more during the day, but most in the evening, when traffic should be decreasing. They occur reasonably often late at night when most computers are turned off and traffic should be lowest.

Do you have any ideas that might help diagnose the cause of problems like this? One thing I have not yet tried, but should have, is updating the firmware of all the switches.