Like most businesses, you may be worried about call quality when moving your phones lines from traditional lines such as ISDN. This is something that you should think about when planning a migration and the most important service criteria you need to consider is the internet connection your calls will be routing over.
As you know, there are various types of internet connection, from standard ADSL to Fibre Broadband to FTTC, through to Ethernet over copper and Ethernet over Fibre – Ethernet Leased Lines.
The key with these products is upload speed, as this will always be slower than the download except for Ethernet Leased Lines. Each call takes approximately 0.1Mb of bandwidth, so if you want 10 calls you need a minimum of 1Mb upload speed.
We advise against using contended broadband services to run your SIP/VoIP calls due to the product not being able to guarantee download and upload speeds. Most ADSL services have a maximum upload speed of 1Mb, therefore this service is only really applicable for small offices. You will also need to add Quality of Service (QoS) if available from your broadband provider to ensure your SIP traffic is given priority.
Broadband can be quicker and would allow many more calls due to download speeds up to 20 Mbps, but again I would recommend adding QoS if available.
Your best choice of service is a Ethernet Leased Line, if you are looking at a Internet service to run your SIP or VoIP telephony services my biggest recommendation would be to upgrade to the most reliable option available. The standard SLA for broadband repair can be 5 days Monday to Friday but can be upgraded to 7 or 8 hour fix 24/7 365 depending on your provider. This is considerably cheaper than ISDN care level 4 which has a 6 hour 24/7 365 SLA.
When choosing your ISP you should ensure they only carry business traffic and if possible have an uncontended network, otherwise contention on their network could cause latency or jitter which will affect your call quality.
We would also recommend that the network you choose has a peering agreement with your SIP/VOIP provider of choice if they don’t provide both services. This will ensure that none of your voice traffic needs to go over the public internet.
Overall the benefits of SIP/VOIP Telephony, the flexibility it gives your business and the cost efficiencies you can achieve using it over your Internet service makes this a compelling cost saving for all businesses.