How the Tritel NG SIP Trunk service works
First it is important to describe the type of environment in which the Tritel NG SIP Trunking solution can be deployed. The customer must meet the following prerequisites:
- There has to be an IP PBX system in place. This can be a mainstream vendor solution such as Cisco Call Manager Express or an open source platform such as Asterisk, Trixbox or 3CX
- Codec support - G.729 (recommended) , G.711 or G.723
- Internet Bandwidth (SAT-3 internet recommended)
Typically, prior to considering SIP trunking a customer will be connected via 1 or more E1 trunks to a PTO. The EI trunk will be directly connected to the IP PBX system and all incoming and outgoing calls will be routed via the PTO. In most cases, there will also be a separate internet connection for email, web browsing and file downloads. The internet connection will often have spare capacity as it is sometimes not fully utilised and is effectively wasted money as the company has to pay for the bandwidth at a flat monthly rate irrespective of whether it is 100% utilised or not. This scenario is illustrated below.
The Tritel NG proposition is that this spare capacity can be sensibly utilised for the transportation of VoIP traffic by routing some or all of the company’s outbound traffic via the internet at significantly lower rates than is possible with the incumbent PTO. All incoming calls will continue to be managed and routed via the PTO who provides the numbering plan for the company.
The earlier diagram is revised below to illustrate how the SIP trunk can be introduced;
In this scenario, the customer can configure their IP PBX such that any digits starting with 00 i.e. international calls are routed over the internet to the Tritel SIP trunk service whilst all other calls are routed via their primary PTO. Alternatively, they can also route all GSM calls along with international calls via the SIP trunk and use the PTO for all land line call. The point is that the customer now has full control to determine which service to use depending on which is the most cost-effective.
Below is a sample configuration to illustrate how simply the service can be implemented. Let’s assume the customer is using a Cisco Call Manager Express IP or gateway, the relevant configuration might look like the following:
dial-peer voice 1 pots
destination-pattern 01.... match any digit starting with 01 i.e. Lagos landlines
port 1/0:1 and route them via port 1/0:1 which is the E1 link to the PTO
dial-peer voice 2 VoIP
destination-pattern 00.... match any digit starting with 00 i.e. international calls
session target ipv4:1.2.3.4 and route them via the IP address of the SIP Trunk Service
These commands are for a Cisco solution but other IP PBX systems such as 3CX and Trixbox have similar configuration options. In fact, most other systems have GUI interfaces which are much easier to configure in this regard.
It is also useful to consider what might happen if there was an outage of some kind which potentially impacts access to the Tritel NG service. For instance, if the internet service at the customer site were to fail for a period of time, how would users within the customer environment be able to make outbound calls. Well, in this situation the calls are simply routed via the legacy PTO as they were before SIP trunking was introduced. The configuration to achieve this on a cisco system is as follows:
dial-peer voice 1 pots
destination-pattern 01.... match any digit starting with 01 i.e. Lagos landlines
port 1/0:1 and route them via port 1/0:1 which is the E1 link to the PTO
dial-peer voice 2 VoIP
destination-pattern 00.... match any digit starting with 00 i.e. international calls
session target ipv4:1.2.3.4 and route them via the IP address of the SIP Trunk Service
preference 1 always prefer this route for international calls
dial-peer voice 3 pots
destination-pattern 00.... match any digit starting with 00 i.e. international calls
port 1/0:1 and route them via port 1/0:1 which is the E1 link to the PTO
preference 2 use this route for international calls if route to SIP fails
The calculator below illustrates the sort of cost saving available to customers who take up this service.
| |
PTO Rates |
SIP Trunk rates |
Rate Differential |
Total Minutes per day (Medium size company) |
Monthly savings (Naira) |
Annual savings (Naira) |
| On net calls |
6 |
10.2 |
-4.2 |
3000 |
0 |
0 |
| Internationals (Europe, UK, USA) |
30 |
8.5 |
21.5 |
1000 |
21,500 |
258,000 |
| GSM calls |
20 |
16 |
4 |
18000 |
72,000 |
864,000 |
| National Calls |
22 |
15 |
7 |
8000 |
56,000 |
672,000 |
| |
|
|
|
|
|
|
| Total |
|
|
|
30000 |
149,500 |
1,794,000 |
Note that this is a randomly generated profile of call distribution for a medium sized company with over a hundred staff. Savings are likely to vary significantly based on the type of calls made by different companies.
Also note that in the above scenario, no savings are likely to be enjoyed for calls for which the destination is the same PTO network to which the customer is directly connected for incoming calls e.g. if the customer is connected to MTS and the destination is another subscriber on the MTS network, then the PTO link will be the cheaper option.
For a trial, please contact Mr. Dare Faleye, Operations Director - Tritel NG, Email: darefaleye@tritel-ng.com Tel:+234 8059791223 or send us a message here.