Questions tagged [voip]

For questions about Voice over Internet Protocol (VoIP) which encompasses various technologies (methods, functions, and encapsulations) for encoding and delivering audio on a network using IP.

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VoIP only for two phones

I would like to connect only two IP phones to talk each other (I have no idea about IP telephony). Is it possible without using a PBX? I mean, just connecting IP phone to IP phone with a straight/...
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2answers
357 views

Is it possible to run CME in a Cisco 1812

I have a router Cisco 1812 (P/N CISCO1812/K9). My question is if it possible to run Call Manager Express into its IOS and which version.
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2answers
182 views

Echo on VoIP Calls

We use Ring Central for VoIP. I inherited this company and so that's the service we have, and I know nothing about VoIP. We have increased our bandwidth to 80Mb down and 6+Mb up, and that's as high ...
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1answer
714 views

How does “dual-line” feature work on Cisco/Avaya IP phones for VOIP?

For below CME configuration which I configured on UC500 where ephones are not configured with dual-line feature and in button command separator 'c'(call waiting) is used. CME_VOICE(config)#ephone-dn ...
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2answers
379 views

Splitting Data and Voice by creating GRE tunnel for Data, using overhead for Voice

A client: 3 sites with L2 links to our Data Centre. I create L3 links by providing IP's both sides. I want to create a GRE tunnel over each link with seperate IPs in order to route Data over these new ...
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1answer
5k views

Double-NAT's Effects on SIP and RTP

What effects does double-NAT have on VoIP? What happens to the traffic in this type of situation and what conditions can occur as a result of it?
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2answers
574 views

How do I diagnose a VoIP issue on a Cisco 2811?

Background Our shop consists of approximately 10~12 Cisco IP phones which then connect to their respective workstations. Each phone is connected to the only switch in the shop which is a Cisco 2950 ...
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1answer
75 views

When voice data is transmitted over the Internet, does session layer add any header to the packet?

For voice data, session layer use SIP, H.323, MGCP, H.248, etc protocols. Do these protocols add any header to the voice data payload? When voice data is transmitted over the Internet, does session ...
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1answer
120 views

“gateway to gateway link” in VoIP?

I want to route some calls to my VoIP number a call center overseas. The call center is telling me that I need to do a "gateway to gateway link" in order to make this happen. I'm not exactly sure what ...
2
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1answer
12k views

Correct ACL rule to open UDP ports for VoIP

I have the current rules in an attempt to open port 5060 and 10000-20000 for my VoIP provider. We are on a Cisco 1921 router. This ACL is applied to the WAN port on the router facing the ISP. Nmap ...
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1answer
110 views

Cisco Unity Connection guest, ESXi host, IP phones, vlan, subnet, ip addresses, qos

I have setup: VLAN 1 and subnet 192.168.1.0/24 for data VLAN 100 and subnet 192.168.100.0/24 for voice IP phones get their IP via DHCP on the subnet 192.168.100.0/24 all other IP devices get their IP ...
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1answer
2k views

Problems Adding IPPhone to VLAN in Packet Tracer

I am trying to add two IPPHONES in a VLAN and it does not seem to be working as the phones are not receiving their ip addresses. I have a router going through a switch and the phones are then ...
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1answer
2k views

Difference between sip proxy and sip outbound proxy? [closed]

What is the basic difference between a sip proxy and a sip outbound proxy. Can sip proxy and outbound proxy be the same?
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4answers
386 views

Cisco Vlan block access

So I have 2 core switches and 1 access switch, I have the vlans 1, 10, 20, 30 and 100. Vlan 10 is voip and what I would like to do is stop anyone on the other vlans from being able to see that subnet, ...
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3answers
3k views

Find IP Address of Cisco 2811

I'm trying to configure the phone configuration on my business' Cisco 2811 router. Without buying a bunch of dongles and connecting through the console port of the router, I'd like to try to SSH or ...
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1answer
89 views

Is there a point to have VLANs if each PC client can access them all?

At work we have a config where VLAN 1 is the main network and VLAN 2 is the phone system. The workstations connect automatically to VLAN 1 but can also access the control panels of each phone through ...
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1answer
4k views

Why and when do we use digit '9' before making an outbound call?

Also explain when do we use this feature (Please explain for both VOIP & Traditional telephony system)? Why we use this feature? what problems shall we face if we don't use '9' before making ...
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1answer
314 views

Is an SBC sufficient and can it NAT

We have a gateway which faces out to our VoIP SP. As we get more users we need some security in front of it. Currently our gateway terminates directly to the SP. We would like to put a SBC in front ...
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4answers
2k views

Can I run two separate internet connections over one Cat5e cable

I have two ISP's coming into the building. One is a T1 that is going to be used for VOIP phones. The second is high speed internet connection going to be used for internet. Each office has one cat5e ...
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1answer
646 views

Optimize WiFi router settings for VoIP

Is there a quick way how to optimize Wi-Fi AP/router settings for better VoIP performance? I use SIP protocol. Can I tweak RTS or fragmentation threshold values for better voice performance? I am ...
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1answer
77 views

Landline phone on VOIP network without an adapter

Today someone asked me if he can make calls using a regular landline phone connected to a VOIP network without using a VOIP adapter, just by using an Ethernet to Telephone line adapter, at his work he ...
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1answer
66 views

ISP Failover On A Converged Network

We have our fiber provider as our primary ISP. We have Comcast as our secondary ISP and our VoIP provider. We can setup the failover between the two ISPs. We also have 19 VoIP phones that are on a ...
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2answers
60 views

Advice on potentially needed subnet expansions

I work for a non-profit with some slightly more antiquated hardware. We have 3 locations, about 700 devices across them. Right now our locations are set up as: Location 1 (Main) - /23 with a DHCP ...
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1answer
884 views

Phone and PC network sharing one wifi bridge

We have a Cisco router from our T-mobile provider, two subnets on two ethernet ports: one subnet for PC data network, one subnet for IP phone network. The subnets have different IP addressing. As per ...
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2answers
116 views

Mostly wireless campus vs. VoIP

We will be replacing our campus network in the next year or two, and we are leaning towards increasing the use of wireless since most people primarily work from laptops & mobile devices. Plus, we ...
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1answer
425 views

VoIP on a remote VPN site

I have a remote site that needs both data and voice. We have a VPN L2L tunnel up and running back to the hospital, no problem. The concern is that I have data and voice on the same VLAN, and it is ...
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1answer
76 views

VoIP, IPsec configuration

I have a topology in GNS3 with an IPsec VPN tunnel between C1 and C2 (https://imgur.com/dnNkssU). In clients networks i am configured a CME and a Softphone. When i make a call the quality is very bad. ...
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1answer
3k views

1-1 NAT on a SonicWall with a DMZ

A new PBX is being installed at one of our clients today, and they have requested that we give them one of our unused public IP addresses(Comcast is the ISP, have a block of IPs) for use with the PBX. ...
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1answer
863 views

Fortigate 90D SD-WAN: VPN and VoIP

i am contemplating the idea of switching our current FG 80D to a 90D and implement SD-WAN using our current 100Mbit fiber circuit (main) and the 4G LTE (cradlepoint) for internet backup. Our current ...
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1answer
53 views

Smart switching calls in a company phone calls

We use VoIP phones in our company. Some people calls and each one connected to first free operator, and each people calls us once a week, we need one more option to make better experience for our ...
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2answers
868 views

how to run multiple IP addresses to be allocated off a single Ethernet port. VoIP

Implementing hosted VoIP with connection of desk handset to Apple Macs. Gbit to desktop Cat5, Aruba 2920 PoE J9836 Layer 3 Switch. Line will be separate 10Mb, separate router too. Question: How can ...
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1answer
129 views

Replacing IP address of connections from AWS towards SIP

We have installed a PBX on AWS and connected it to our on-prem Router via VPN. My on-prem router is connected to the SIP provider via a physical connection with another on-prem MUX device (device ...
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1answer
572 views

Cisco 7960 SIP phone background image issues

I have an asterisk home PBX and I recently got a Cisco 7960G on eBay. So far I got everything working but the background images are quite tricky. I followed one short how-to and I was able to actually ...
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1answer
313 views

QoS implementation for VoIP network

We are in VoIP business and running RTP/SIP traffic 80% in our network we have other servers also like www and monitoring and operation, our network is very flat and simple also we have very basic ...
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1answer
264 views

Configure switch in GNS3

Is there any way to configure a switch in GNS3?
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1answer
69 views

VoIP Provider and Phone Number Routing Questions

I am fairly familiar with VoIP and I have my own VoIP PBX, and my provider is Twilio (for Voice) and CallCentric (for Fax). But How do providers like Twilio work exactly? More specifically: How do ...
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1answer
352 views

ESI PBX LAN-only VoIP phone forwarding thru IPSec tunnel - remote router sees packets but not phone, doesn't forward

Okay, so we have an older X-Class ESI PBX system, an ESI IVX 128x FSIII [see below for link]. We have an LNC card installed in it, which allows for the use of up to 12 LAN-only VoIP phones. We have an ...
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1answer
994 views

Real IP phone in GNS3 Problem

I am trying to link this configuration to a real SPA 303 IP phone but I do not know where to begin with this. I have the physical IP Phone, but I want to run it through the simulated environment that ...
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1answer
1k views

How to use a layer 3 switch for QOS between gateway and hosts?

In the following scenario, is it possible to prioritize VOIP/RTP from x.x.x.51 through the gateway with a Cisco switch, and how? I need to prevent x.x.x.50 from saturating the WAN connection. ...
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2answers
2k views

CISCO CUBE is as SBC suitable for ISP

I am currently planning a voice network and test different ways. Currently a classic IP network with various Cisco Routers is used to bound different media (fiber, copper, MPLS) and route to a classic ...
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1answer
177 views

FXO to GSM routing

I am new to VoIP so apologize if this is a dump question I want to accept a traditional telephone call (FXO) channel and based on the callers extension selection I want to switch the call to set of ...
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0answers
53 views

TCL Tool Command Language tclsh - Script for Cisco SPA508G Phone Sidecar Auto-attendant

Using Cisco SPA508G phones with SPA500S Sidecar Console. In the Cisco UI Sidecar programming is the script: fnc=blf+sd+cp;sub=108@$PROXY;nme=Steve J. I need both sub=108@$PROXY and sub=408@$PROXY ...
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0answers
203 views

Changing DSCP values in a Cisco Switch [closed]

We have an endpoint which cannot tag outgoing RTP packets as 46 (EF).... Currently they happily churn out as 0 Can the Cisco switch it is entering, recognise it's RTP traffic and then change the ...
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0answers
51 views

QOS - the need for it and verifying it

Just some straightforward questions, hope gurus here can shed some light 1) show int - output queue -> this is the hardware queue (tx-ring) or this is the software queue ? if I see drop, this means ...
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1answer
257 views

Does UDP work for Load Balancing?

while I was working today on router, My senior said that since VoIP protocol works on UDP, it doesn't support load balancing, which I couldn't quite understand. Can someone enlighten me on this. We ...
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0answers
70 views

Issue with voice performance between two ip phones at the same site connecting to two different CUCM?

I have one branch which is (branch-1) with two groups of ip phones, one group is connecting to CUCM-1 in HQ and the other group is connecting to CUCM-2 in the branch (branch-1) and the connectivity ...
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2answers
64 views

How does UDP provide continuous sound in VOIP even though segments are discrete?

I would like to know how does UDP achieve continuity in VOIP or in any streaming service.
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1answer
698 views

qos inside vpn, possible or not ? I read yes and no

I am wondering if possible to do QOS (or similar action) inside vpn tunnel to a cloud server. the goal is to reserved bandwith for voip traffic. I read that you can with GRE and other people said, ...
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1answer
713 views

Cell-phones and protocol-stack [closed]

When making a phone-call these day - the datastream is divided into packages, isnt it? But which protocol-stack is used then? VOIP is using tcp-ip but but what about cell-phones? For instance - the ...
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1answer
1k views

Use a Switch or Router for PoE on VOIP system

I have a question regarding if a switch or router is the way to go in my situation. We have a modem through Comcast that only has one available port on it right now and we are getting a VOIP system ...