How to calculate the total number of calls in a network?

Dear all,
If I want to measure on a node (in my case a IMS-core node) the number of calls that occur upon it, it seems correct to me to add, in a certain period of time (for example in one hour), the number of Originating and Terminating calls ( Call Originating + Call Terminating) counted by the two respective node counters.
The doubt comes to me when I want to measure the total number of calls on the entire network. Suppose there are two nodes in the network and if I want to count the total number of calls that take place on the network, in a given period of time, if I add Orig and Term from the node 1 and Orig and Term from the node 2 (orig_node_1 + term_node_1 + orig_node_2 + term_node_2), I think I am doing it wrongly because I introduce a double counting (i.e. a single call from user A to user B is triggered two times: the first time by the originating counter of node_1 and a second time by the terminating counter of node 2). In your opinion, what is the appropriate way to calclulate the total number of call in a network? Do you think it is better to take into your calculation only the originating side of all the nodes in the network? What is your method to do it?
Thank you.

This is why IMS has the Session-ID header,

If you count the total number of Session-IDs you see on SIP Calls (INVITEs) that’ll give you the number of unique calls.

If subscriber A on Node A, calls subscriber B n node B, the INVITE will have the same Session-ID. so would count as one call.


@nickvsnetworking thank you!
Honestly, on the different technologies I worked on (Huawei, Ericsson, Nokia), I never noticed a counter able to discriminate a unique call through Session-ID or I simply missed this detail studying the counters. I’ll take a better look on that but I am pretty sure that the counters I used (and I’m currently using) are not based on this session-ID but they simply count the number of INVITEs occurred on the node. So, in this case, you’d agree with me that adding values from Originating and Terminating INVITEs across multiple nodes in the same network is an inaccurate way?

If this is for metrics, then the number of calls per node is fine, it gives you an understanding of the number of calls easch TAS/CSCF is handling.

But if it’s for charging, that’s where you need to be able to differentiate them so you can bill correctly.

What is your use case?

You can concatenate the nodeid with orig1.

Similarly concatenate nodeid with orig2.

Similarly concatenate nodeid with term1 and also concatinate nodeid with term2.

Then remove the duplicates.

This will give you total calls.

Yes, it’s for metrics… in fact I export these values in some reports.

I agree with you that by adding “term” and “orig” it gives a good understanding of the number of calls each CSCF is handling but I think it’s OK when I focus on a single node. On the other hand, if I want to export the total number of single calls occured on the network across the different CSCFs, if I sum “orig” and “term” INVITE requests, my suspect is that I am introducng double counting. The counter I am using have these descriptions:

ORIG–>This measurement entity counts the number of INVITE requests received by the S-CSCF for originating sessions in a measurement period.
TERM–>This measurement entity counts the number of INVITE requests received by the S-CSCF for terminating sessions in a measurement period.

Also looking at the relative signalling call-flows, I presume that if I sum these two counters for all nodes on the network I’ll incude in my calculation a double counting, because at the first originating INVITE I add a second terminating INVITE related to the same call. If I want to export a value which expresses the whole number of calls in the network and not the total number of INVITEs around each node I have to pay my attention to other counters maybe based on call session-ID as you suggested.

thank you @TechHW I think I cannot concatenate because I have access only to the node counters which count the simple INVITEs without any associations with calls or users