packets drop (QoS)

[ohassairi]

Hello

to garantee a bw for oracle application i configured this in HQ (oracle server is there)

class-map All-Traffic
match any
exit
!

policy-map G01-Policy
class All-Traffic
   shape  average 16000000 (the wan speed is 16Mbps)
   service-policy outbound-Policy
exit
!

access-list 195 permit ip 200.0.0.0 0.255.255.255 any
!
class-map match-all DB_traffic
match access-group 195
exit

!
policy-map outbound-policy
class DB_traffic
    bandwidth 4096 (i want to garantee 4Mbps for DB)
exit
class class-default
    fair-queue
exit
exit

interface GigabitEthernet0/1

service-policy output G01-Policy

however i noted that:

-1 have 2 default classes? is this normal?

2- many packets are dropped in the 1st default class (see below) Can you explain why? will this make other applications slow?

core-router-labor#sho policy-map interface gigabitEthernet 0/1
GigabitEthernet0/1

  Service-policy output: G01-Policy

    Class-map: All-Traffic (match-all)
      30803364 packets, 9676560228 bytes
      30 second offered rate 4737000 bps, drop rate 10000 bps
      Match: any
      Queueing
      queue limit 64 packets
      (queue depth/total drops/no-buffer drops) 0/26970/0
      (pkts output/bytes output) 30776380/9654641198
      shape (average) cir 16000000, bc 64000, be 64000
      target shape rate 16000000

      Service-policy : outbound-policy

        Class-map: DB_traffic (match-all)
          4083861 packets, 800694517 bytes
          30 second offered rate 103000 bps, drop rate 0 bps
          Match: access-group 195
          Queueing
          queue limit 64 packets
          (queue depth/total drops/no-buffer drops) 0/0/0
          (pkts output/bytes output) 4083861/800694517
          bandwidth 4096 kbps

        Class-map: class-default (match-any)
          26719489 packets, 8875853172 bytes
          30 second offered rate 4636000 bps, drop rate 10000 bps
          Match: any
          Queueing
          queue limit 64 packets
          (queue depth/total drops/no-buffer drops/flowdrops) 0/26970/0/26970
          (pkts output/bytes output) 26692519/8853946681
          Fair-queue: per-flow queue limit 16

    Class-map: class-default (match-any)
      0 packets, 0 bytes
      30 second offered rate 0 bps, drop rate 0 bps
      Match: any

      queue limit 64 packets
      (queue depth/total drops/no-buffer drops) 0/0/0
      (pkts output/bytes output) 12/12431

[Joseph W. Doherty · Accepted solution]

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however i noted that:

-1 have 2 default classes? is this normal?

2- many packets are dropped in the 1st default class (see below) Can you explain why? will this make other applications slow?

1) Yes it is.  CBWFQ always has a default class.

NB: if you want to match all packets, you could have done:

policy-map G01-Policy

class class-default

   shape  average 16000000 (the wan speed is 16Mbps)

   service-policy outbound-Policy

2) Likely because queue depth isn't deep enough to support 16 Mbps.  For a single TCP flow to obtain optimal performance, as a rough rule of thumb, egress queue should be sized to about half of BDP (bandwidth delay product).

QoS features vary per platform and IOS version, but try something like:

policy-map outbound-policy

class DB_traffic

    bandwidth 4096 (i want to garantee 4Mbps for DB)

class class-default

    fair-queue

queue-limit 1024 (not 100% positive this is correct syntax)

Adjust as necessary.