Summary

Echo is a difficult problem and not one that can be readily solved without access to the end-to-end circuit. Echo cancellation devices at the boundary of the VoIP system attempt to reduce echo that is of no concern in the PSTN so that it cannot be heard in the IP telephony environment. CA UC Monitor provides a quick, overall rating of the success of this effort in the form of ACOM values for all gateway calls made on the monitored network, as well as some additional details, such as ERL, Signal In, and Signal Out, that are essential for troubleshooting echo problems.

Helpful References

CA Infrastructure Management products: http://www.ca.com/us/infrastructure-management.aspx
Troubleshooting Echo Problems between IP Phones and IOS Gateways: http://www.cisco.com/en/US/tech/tk652/tk698/technologies_tech_note09186a0080149a1f.shtml
Using the show call active voice Command to Troubleshoot Voice Quality Issues: http://www.cisco.com/en/US/tech/tk652/tk698/technologies_tech_note09186a008019ab88.shtml#topic6
IP Telephony Advanced Troubleshooting: http://www.cisco.com/web/CA/events/pdfs/IP_Telephony_Advanced_Topics_And_Troubleshooting.pdf
G.168: Digital network echo cancellers: http://www.itu.int/rec/T-REC-G.168-200408-S/en