Summary

CCS has evolved to address the limitations of the CAS signaling method. CCS has the following advantages over CAS:

• Much faster call set-up time

• Greater flexibility

• Capacity to evolve

• More cost effective than CAS

• Greater call control

Most CCS calls can be set up in half the time it takes to set up CAS calls. CCS achieves greater call control because no contention exists between signaling and user traffic as it does with in-band CAS. Because the subscriber cannot generate particular signals intended for inter-switch (core network) signaling, CCS offers a greater degree of protection against fraud than analog CAS methods.

CCS has the following disadvantages in comparison to CAS:

• CCS links can be a single point of failure—a single link can control thousands of voice circuits, so if a link fails and no alternative routes are found, thousands of calls could be lost.

• There is no inherent testing of speech path by call set-up signaling, so elaborate Continuity Test procedures are required.