Cisco 3850,3750,4948E Layer 3 Egress WAN QoS for prioritization ..Enterprise QOS Designing..!

 Let's Look at some simple examples of enterprise QOS designing  (of the Catalyst 3550,3750,4948E series ) 

There is a 3-step process, We will first configure the class map, then the policy map, apply the policy map to an interface.

See the example Layer 3 Egress/WAN QoS policy configuration below:

1.  Configure class-map first (class-map matches the tags)

        class-map match-any VOICE-RTP              
              match dscp ef
        class-map match-any VIDEO-INTERACTIVE
              match dscp af41
              match dscp cs4
        class-map match-any CALL-SIGNALING
              match ip dscp cs3
              match ip dscp af31        
         class-map match-any SCAVENGER
              match ip dscp cs1

2.  Then Policy-map allocates percentage of bandwidth & reservations based on class

policy-map WAN-PRIMARY
        class VOICE-RTP
              priority level 1 percent 10
        class VIDEO-INTERACTIVE
              priority level 2 percent 20
        class CALL-SIGNALING
              bandwidth percent 5
        class SCAVENGER
              bandwidth percent 10
        class class-default
              shape average 9500000000***

Then Service-policy applies policy-map to interface

interface Gi1/0/1

     service-policy output WAN-PRIMARY

Note:

***shape average should be lowered by bandwidth minus 5 percent, in bits

for 1Gb it would be 950Mb 

the five percent was rule of thumb for 100Mb 

so took 1Gbps knocked it down to 950Mb 

for gig it's 950 million = 950,000,000 bits, 

and 95Mb shape average for 100Mb circuit

Bits Per Second Cheatsheet:

• 1 Kbps = 1,000 bps    (one thousand bits per second)
• 100 Kbps = 100,000 bps    (100 thousand)
• 1 Mbps = 1,000,000 bps    (1 million)
• 100 Mbps = 100,000,000 bps    (100 million)
• 1 Gbps = 1,000,000,000 bps      (1 billion)
• 10 Gbps = 10,000,000,000 bps    (10 billion)