QoS is also in the IPBase-Image Same functionality in the Catalyst 2960 and 3560
Dipl.-Ing. Karsten Iwen, CCIE #14602 (Security)
http://Security-Planet.de
7 October, 2007
QoS on Catalyst 3750
Enabling QoS globally
By default QoS is disabled
Sw(config)# do sh mls qos
QoS is disabled QoS ip packet dscp rewrite is enabled
Also with „QoS ip packet dscp rewrite is enabled“ the switch does not alter any dscp-labels until QoS is enabled globally Sw(config)# mls mls qos Sw(config)# do sh mls qos
QoS is enabled QoS ip packet dscp rewrite is enabled
Queue 3 is configured with a first threshold of 40%, a second threshold of 60%. 100% of the allocated memory is guaranteed, the queue is allowed to have 200% of the memory before packets are dropped.
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QoS on Catalyst 3750
Weighted Tail Drop (WTD)
CoS or DSCP-values have to be matched to thresholds:
for Queue 3, frames with a CoS of 0, 1, 2 or 3 are mapped to threshold 1 (40%), CoS 4 is mapped to threshold 2 (60%).
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QoS on Catalyst 3750
Ingress-Queues
two Ingress-queues, the second queue is the priority-queue by default (can be configured) Frames with a given CoS- or DSCP-value are assigned to the input-queues WTD is also supported
SRR controlls at which rate packets are sent supports two modes:
shaped mode the egress queues are guaranteed a percentage of bandwidth and are also shaped to this bandwidth. This mode is only supported on egress shared mode the queues are guaranteed a bandwidth based on the configured weight. This mode is supported on ingress and egress
Queue 1 and 2 are operated in shaped mode (the weight is > 0) with a bandwith shaped to 1/8 of the interface-bandwidth (12,5%) for queue 1 and ¼ (25%) for queue 2. These bandwidths are also guaranteed. Queues 3-4 are operated in shared mode (the weight is 0)
exceed-action drop Sw(config)# policy-map AggPolicy Sw(config-pmap)# class Server1 Sw(config-pmap-c)# police aggregate agp1 Sw(config-pmap-c)# class Server2 Sw(config-pmap-c)# police aggregate agp1 Sw(config)# interface gigabitethernet1/0/1 Sw(config-if)# service-policy input AggPolicy
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QoS on Catalyst 3750
AutoQoS
enables QoS can trust the cisco-phone, cisco-softphone and cos corrects the cos to dscp-map configures the input- and output-queue-settings configures a policer on the voice-traffic when trusting a phone or softphone
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QoS on Catalyst 3750
AutoQoS
With „voip trust“
Sw(config-if)# auto qos voip trust Sw#show run interface FastEthernet1/0/1
interface FastEthernet1/0/1 switchport trunk native vlan 255 switchport mode access srr-queue bandwidth share 10 10 60 20 priority-queue out mls qos trust cos auto qos voip trust
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QoS on Catalyst 3750
AutoQoS
With „voip trust“
Sw#sh mls qos interface fastEthernet 1/0/1
FastEthernet1/0/1 trust state: trust cos trust mode: trust cos trust enabled flag: ena COS override: dis default COS: 0 DSCP Mutation Map: Default DSCP Mutation Map Trust device: none qos mode: port-based
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QoS on Catalyst 3750
AutoQoS
With „voip cisco-softphone “
Sw(config-if)# auto qos voip cisco-softphone Sw#sh mls qos interface fastEthernet 1/0/1
FastEthernet1/0/1 Attached policy-map for Ingress: AutoQoS-Police-SoftPhone trust state: not trusted trust mode: not trusted trust enabled flag: ena COS override: dis default COS: 0 DSCP Mutation Map: Default DSCP Mutation Map Trust device: none qos mode: port-based 29
QoS on Catalyst 3750
AutoQoS
With „voip cisco-softphone “
Sw(config-if)# show run
! mls qos map policed-dscp 24 26 46 to 0 ! class-map match-all AutoQoS-VoIP-RTP-Trust match ip dscp ef class-map match-all AutoQoS-VoIP-Control-Trust match ip dscp cs3 af31 !
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QoS on Catalyst 3750
AutoQoS
With „voip cisco-softphone “
! policy-map AutoQoS-Police-SoftPhone class AutoQoS-VoIP-RTP-Trust set dscp ef police 320000 8000 exceed-action policed-dscp-transmit class AutoQoS-VoIP-Control-Trust set dscp cs3 police 32000 8000 exceed-action policed-dscp-transmit !
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QoS on Catalyst 3750
AutoQoS
With „voip cisco-softphone “
! interface FastEthernet1/0/1 srr-queue bandwidth share 10 10 60 20 priority-queue out auto qos voip cisco-softphone service-policy input AutoQoS-Police-SoftPhone
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QoS on Catalyst 3750
AutoQoS
With „voip cisco-phone “
Sw(config-if)# auto qos voip cisco-phone Sw#sh mls qos interface fastEthernet 1/0/1
FastEthernet1/0/1 Attached policy-map for Ingress: AutoQoS-Police-SoftPhone trust state: not trusted trust mode: trust cos trust enabled flag: dis COS override: dis default COS: 0 DSCP Mutation Map: Default DSCP Mutation Map Trust device: cisco-phone qos mode: port-based 33