CUCM Sip Trunk Inbound/Outbound CSS Clarification

[dan hale]

Hi All, I need a little help understanding the Inbound Calls and Outbound Calls section off the SIP Trunk Page when you create a SIP Trunk in CUCM.

I need to set the CSS appropriately for which direction it is going.

If I have the below call flow

PSTN ----> Gateway(MGCP) -----> CUCM ---> CUCM (SIP Trunk) -----> Fax Server

From what perspective is the inbound and outbound for my CSS calls? If a call comes in from the PSTN destined for my fax server would that be considered an Inbound call to the sip trunk or outbound to the Fax Server? If a fax came from the FAX server destined for the PSTN is that considered and outbound call to the PSTN or inbound to CUCM from the fax server?

I'm using CUCM version 9.x

Thanks,

Dan

[Jaime Valencia · Accepted solution]

If the call is coming to that SIP trunk, it's inbound

If the call is coming from a device in CUCM, it's outbound.

A call can have both, an inbound and outbound trunk in CUCM if that's the call flow you configured.