This sets the count threshold of egress buffer overflow events for CBR traffic that, within the corresponding alert period, triggers a threshold-crossing alert on this port. Because CBR is the highest-priority, most latency-intolerant traffic class among the four tracked here (CBR, ABR, VBR1, VBR2), this threshold on this specific port is typically set more conservatively, lower, than its ABR/VBR counterparts, since even a small number of CBR buffer overflows can represent noticeable service degradation. Setting this threshold to just 5 on this port, compared to a much higher threshold for the ABR class, reflects that even a handful of egress overflows affecting CBR voice traffic on this port is worth immediate attention.