Skip to main content
CallTower Solutions Center

Cisco - End-to-End Signaling


The purpose of this Article is to work you through viewing the legs of End-toEnd Signaling.

Inbound Calls:


Calls come into PSTN or Public Switch Telephone network this will then hit our SBC Session border controller which acts as a voice firewall or router and is a edge device.

Internal Leg:

Calls will then flow from the SBC to the Cisco Session Manager which will look for a route pattern match within the Cisco Clusters or the HCS pods.


Customer Leg:

When a route pattern is found the call is then routed to the customers network, from the customers network it will then route to the end point. However if the customer is on a Cisco Cluster it will follow this flow based on a translation pattern or directory number depending on the customer. 




Outbound Calls:

Internal Calls:

In the case for Internal outbound calls these will stay on the customers network as the call will flow to the Cisco cluster or HCS pod and will route from there directly to the End point.


Outbound PSTN (external):

Customer Leg:

Seeing as this is now originating from the customer this will now begin at the customer leg. The call will then be routed to the HCS pod or Cisco Cluster.

Internal Leg:

From the HCS pod or Cisco Cluster this will be routed to the Cisco Session Manager, and from the Cisco Session Manager to the SBC.


Finally from the SBC this will be routed to the PSTN.

  • Was this article helpful?