Our network router is currently configured to use QoS (CBWFQ with LLQ) as we do use VoIP. In our router config, there's following statement that I've a couple of questions about that I hope that someone can help to shed some lights..
class-map match-all Match-All-VC
match access-group 115
class-map match-all VoIP-RTP
match access-group 110
access-list 110 permit ip any any precedence critical
access-list 110 permit ip any any dscp ef
access-list 110 permit tcp any eq 1720 any
access-list 110 permit tcp any any eq 1720
access-list 110 permit ip any any precedence flash
access-list 115 permit tcp any any precedence flash-override
A. How many priority queues are allowed per serial interface? The above policy is applied to all of our serial interfaces.
B. What is the purpose of the command "precedence flash" and "precedence flash-override"? I believe that their priorities level are 4 and 3 respectively, but I am not sure of what it does.