This sets how often the card re-raises an alert for sustained congestion in the VBR2 queue on the switching port's Pearl ASIC. As the lower-priority VBR class's congestion signal, this alert firing without its VBR1 counterpart also firing tells the admin the pressure is specifically building in the lower-tier queue, which is generally lower urgency but still worth tracking before it escalates to overflow. For example, a VBR2-only congestion alert pattern suggests lower-priority traffic is filling up first, giving the admin a chance to shift or rate-limit that traffic before it affects the higher-priority VBR1 queue sharing the same port.