Understanding QoS

Studying QoS and playing with it ... quick dummy questions ..
Ok, I have this policy

!policy-map QoS_Output_Policy class VoIP priority percent 35 set ip dscp ef
class Video priority percent 25 set ip dscp af41 class SIP bandwidth
remaining percent 25 set ip dscp af31 class Data bandwidth remaining percent
15 set ip dscp af21 class class-default fair-queue set dscp
default!!interface GigabitEthernet0/2 duplex full speed 100 service-policy
output QoS_Output_Policy!
* Is by default 75% (75MB) of 1 GB bandwidth is available for use?* I can't
apply "max-reserved-bandwidth" to a gig interface. How can I use the total 1GB
bandwidth?* "priority percent 35" means LLQ and VoIP class gets 26MB (75MB *
35%)?* "bandwidth remaining percent 25" SIP traffic gets 12MB (75MB - 26MB =
46MB * 25% = 12MB)?* How can I verify it there is indeed a congestion
happened?
DC1-3FL-RTR001#sh policy-map int g0/2 GigabitEthernet0/2
  Service-policy output: QoS_Output_Policy
    queue stats for all priority classes: Queueing queue limit 64
packets (queue depth/total drops/no-buffer drops) 0/0/0 (pkts
output/bytes output) 60579572/8599620493
    Class-map: VoIP (match-any) 58813111 packets, 8056468225 bytes 5
minute offered rate 0000 bps, drop rate 0000 bps Match: ip dscp ef (46)
1167959 packets, 86399962 bytes 5 minute rate 0 bps Match:
protocol rtp audio 57632956 packets, 7968100335 bytes 5 minute
rate 0 bps Match: protocol rtcp 12196 packets, 1967928 bytes
5 minute rate 0 bps Priority: 35% (35000 kbps), burst bytes 875000, b/w
exceed drops: 0
      QoS Set dscp ef Packets marked 58813111
    Class-map: Video (match-any) 1766463 packets, 543152268 bytes 5
minute offered rate 0000 bps, drop rate 0000 bps Match: ip dscp af41 (34)
1653227 packets, 526896986 bytes 5 minute rate 0 bps Match:
protocol rtp video 0 packets, 0 bytes 5 minute rate 0 bps
Match: protocol video-over-http 0 packets, 0 bytes 5 minute rate
0 bps Match: access-group name video 113236 packets, 16255282
bytes 5 minute rate 0 bps Priority: 25% (25000 kbps), burst bytes
625000, b/w exceed drops: 0
      QoS Set dscp af41 Packets marked 1766463
    Class-map: SIP (match-any) 1125626 packets, 314867881 bytes 5
minute offered rate 6000 bps, drop rate 0000 bps Match: ip dscp af31 (26)
572572 packets, 98559349 bytes 5 minute rate 3000 bps Match:
protocol sip 553043 packets, 216307750 bytes 5 minute rate 3000
bps Match: ip dscp cs3 (24) af31 (26) 11 packets, 782 bytes
5 minute rate 0 bps Queueing queue limit 64 packets (queue
depth/total drops/no-buffer drops) 0/0/0 (pkts output/bytes output)
1125626/314867881 bandwidth remaining 25% QoS Set dscp af31
Packets marked 1125626
    Class-map: Data (match-any) 0 packets, 0 bytes 5 minute offered
rate 0000 bps, drop rate 0000 bps Match: ip dscp af21 (18) 0
packets, 0 bytes 5 minute rate 0 bps Queueing queue limit 64
packets (queue depth/total drops/no-buffer drops) 0/0/0 (pkts
output/bytes output) 0/0 bandwidth remaining 15% QoS Set dscp
af21 Packets marked 0
    Class-map: class-default (match-any) 791611850 packets, 912546925544
bytes 5 minute offered rate 16514000 bps, drop rate 0000 bps Match:
any Queueing queue limit 64 packets (queue depth/total
drops/no-buffer drops/flowdrops) 0/5/0/5 (pkts output/bytes output)
791611623/912502991512 Fair-queue: per-flow queue limit 16 packets
QoS Set dscp default Packets marked 791481954

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Received on Thu Jun 27 2013 - 16:41:28 ART