SIP Early Offer vs Delayed Offer

[francisg]

ITSP -- CUBE -- CUCM -- SIP/SCCP IP Phone

ITSP -- CUBE -- CUCM -- MGCP/QSIG to turret System

ITSP -- CUBE -- CUCM -- SIP to another Turret system

What is the proper setup for configuring a my SIP trunks?

The CUBE is configured for EO going to the ITSP and CUCM

CUCM is configured to use DO via the SIP profile.

CUCM SIP trunk also has "MTP required" unchecked.

What is the difference between setting the SIP Profile "early offer support for voice and video calls" to Best Effort (do not insert MTP) and Mandatory (insert MTP if needed)?

[R0g22]

It really depends how do you want things to be setup. ITSP's more often than not require EO therefore CUBE's are configured for EO. Do can setup CUCM to do EO if you are running into any restriction on the CUBE that might prevent it from doing a DO to EO interop.

For your other question -

1. Best effort - CUCM will minimize the MTP allocation and try it's best to not allocate one when initiating a EO SIP call.
2. Mandatory - CUCM will always insert/invoke an MTP to initiate a EO sip call.