Log In

Come Join Us!

Are you a
Computer / IT professional?
Join Tek-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Tek-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here


What is better, SIP Trunk or E1 ISDN PRI?

What is better, SIP Trunk or E1 ISDN PRI?

What is better, SIP Trunk or E1 ISDN PRI?

Nowadays, ISPs/Telco are now offering SIP Trunks as an alternative to E1 ISDN PRI for VoIP Phone System deployment. Do you have any experience using SIP Trunks from the ISP/Telco? Is it easier to manage than E1 ISDN PRI? Is it cheaper? Would you recommend it?

"It is an equal failing to trust everybody, and to trust nobody."

RE: What is better, SIP Trunk or E1 ISDN PRI?

SIP voice paths are substantially cheaper, but PRI is 1000 times more reliable.

Marv ccna

Sales, Installation & Service for Norstar, BCM, Samsung & Allworx Serving Ottawa and Eastern Ontario since 1990

RE: What is better, SIP Trunk or E1 ISDN PRI?

I disagree with the reliability, as long as you take into account that you should have a separate circuit for your sip traffic , appropriate bandwith for the usage of the circuits , security)(firewall, SBC) sip is reliable as PRI , it is certainly much more flexible with different geographic number presentation , DR scenarios , end user interface (most providers)

At the end of the day it is how you design the solution , i have only come across unreliable SIP issues when somebody is trying to use the same circuit for data and voice , or not listened to implementation recommendations.


RE: What is better, SIP Trunk or E1 ISDN PRI?

If your talking just voice then PRI is better quality if you're talking price and features then go with SIP. Remember at this time for voice anyway:
•PRI has a guaranteed Quality of Service (QoS)
•SIP Trunking is typically Best Effort

RE: What is better, SIP Trunk or E1 ISDN PRI?

But g711 provides 64k call quality, so again it depends on who your provider is and what your circuit type.


RE: What is better, SIP Trunk or E1 ISDN PRI?

We run 30+ channel SIP trunks on call centres doing 5K calls / day on 10Meg leased lines, and you wouldn't know what difference between that and an ISDN call.

General Geek

RE: What is better, SIP Trunk or E1 ISDN PRI?

SIP can run G.711 which is what an ISDN uses. So quality is, or can be, the same.

SIP does support QoS and providers can supply guaranteed dedicated circuits.

Problem is, people expect SIP to be cheaper so won't pay for what is needed to do it right.

The bigger the requirement, the more likely you are to get what is needed. A small site going for a SIP will want to share the traffic on their data ADSL, and then complain like help when it sounds like crap when they send an email!!! Big sites will get a proper link or a QoS capable link.

Look at every implementation on its own merits.

Jamie Green

Avaya Registered Specialist Engineer

RE: What is better, SIP Trunk or E1 ISDN PRI?

I'd say the issues with SIP Trunks are mainly related to poor maintainer and provider skills/setup.

The SIP Trunk is easier to relocate and usually there's no fee involved.
You'll may also get better fall back options, either to a different location or have a router with dual WAN.

In my experience downtime is more or less the same for PRI/SIP, usually it involves an excavator or really bad weather.

Use providers that has a SBC on their end and pick one that has been in the game for a while.
Some has even made PB specific manuals for setting up the trunk, making the job a walk in the park.

Kind regards

Mille viae ducunt homines per saecula Romam

RE: What is better, SIP Trunk or E1 ISDN PRI?

I agree with Gunnar.
SIP has the advantage that you can use the data Internet as backup if you separate voice and data Internet connection while PRI is a single connection without real failover if we take the analog failover line out of the equation which is just a silly excuse and not a real failover.

Joe W.


“This is the end of the world, make sure to buy your T-shirt before it is too late"
Original expression of my daughter

RE: What is better, SIP Trunk or E1 ISDN PRI?

The primary advantage of SIP,as has been mentioned is that it allows for whoe numbering ranges to be moved from location to location very easily. This is simply not possible with PRI.
Diverse network paths also protect against man-with-digger attacks. Again, not possible with ISDN.

However as SIP is packet based, the transport medium is crucial... Contention, Bandwidthm, Latency and packet loss are all enemies of good quality SIP (and VoIP in general) so a cr*p dsl internet connection shared with data, with a cheapo router will leave you with issues. Proper dedicated, diverse circuits to teh provider cloud, with traffic prioritisation with a proper SBC and firewall will give a good quality service. (Extreme examples, I accept)

The problem is that SIP done properly costs money and this means that it doesn't scale down well. People doing SIP on the cheap usually lead to poor results

Take Care

I have always wished that my computer would be as easy to use as my telephone.
My wish has come true. I no longer know how to use my telephone.

RE: What is better, SIP Trunk or E1 ISDN PRI?

Just to add to this, one MASSIVE advantage of SIP is it's not locations specific, you can have a single number and (dependant on carrier) have it not just it in country, but throughout the world. We have multiple different UK numbers that terminate in another parts of Europe, and on the same circuits, we have French, Dutch and Spanish circuits terminating in the UK.

But of course, we pay for it, but a hell of a lot less than it would cost to forward 20,000 calls a day around Europe.

Robert Wilensky:
We've all heard that a million monkeys banging on a million typewriters will eventually reproduce the entire works of Shakespeare. Now, thanks to the Internet, we know this is not true.


Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Tek-Tips Forums free from inappropriate posts.
The Tek-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Tek-Tips forums is a member-only feature.

Click Here to join Tek-Tips and talk with other members!

Close Box

Join Tek-Tips® Today!

Join your peers on the Internet's largest technical computer professional community.
It's easy to join and it's free.

Here's Why Members Love Tek-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close