The object specifies which echo canceller is present
on the interface.
echoCancellerStandard - for this echo canceller valid
values of cvIfCfgEchoCancelCoverage are echoCanceller8ms
through echoCanceller32ms; cvIfCfgEchoCancelWorstERL is
not valid.
echoCancellerExtended - for this echo canceller valid
values of cvIfCfgEchoCancelCoverage are echoCanceller24ms
through echoCanceller128ms; cvIfCfgEchoCancelWorstERL is
valid.