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AutoQos-VOIP
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Contents
AutoQoS - VoIPLast Updated: June 16, 2011
The AutoQoS -- VoIP feature allows you to automate the delivery of quality of service (QoS) on your network and provides a means for simplifying the implementation and provisioning of QoS for Voice over IP (VoIP) traffic.efr Finding Feature InformationYour software release may not support all the features documented in this module. For the latest feature information and caveats, see the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the Feature Information Table at the end of this document. Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required. Prerequisites for AutoQoS - VoIP
Restrictions for AutoQoS - VoIPGeneral Restrictions
The AutoQoS -- VoIP feature is supported on low-speed ATM PVCs in point-to-point subinterfaces only. The AutoQoS -- VoIP feature is supported on high-speed ATM PVCs in any type of subinterface.
Serial Interface Restrictions
Frame Relay DLCI Restrictions
When MLPoFR is configured, this IP address is removed and put on the MLP bundle. The AutoQoS -- VoIP feature must also be configured on the ATM side of the network.
ATM PVC Restrictions
When MLPoATM is configured, this IP address is removed and put on the MLP bundle. The AutoQoS -- VoIP feature must also be configured on the ATM side of the network. Information About AutoQoS - VoIP
Benefits of AutoQoS - VoIPThe key benefits of the AutoQos -VoIP feature include the following:
Design ConsiderationsGeneral QoS Requirements
Classification is used to differentiate the voice packets from the data packets and handle the voice packets appropriately. The LLQ (specifically, PQ) is applied to the voice packets to meet the latency requirements. With cRTP, the 40-byte IP header of the voice packet is reduced from 2 to 4 bytes, thereby reducing voice bandwidth requirements. cRTP must be applied at both ends of a network link. LFI is used to reduce the jitter of voice packets by preventing voice packets from getting delayed behind large data packets in a queue. LFI must be applied at both ends of a network link. Bandwidth Implications
The AutoQoS -- VoIP feature uses the bandwidth at the time the feature is configured. AutoQoS -- VoIP does not respond to changes made to bandwidth after the feature is configured. For example, if the auto qos voip command is used to configure the AutoQoS -- VoIP feature on an interface with 1000 Kbps, the AutoQoS -- VoIP feature generates configurations for high-speed interfaces. However, if the bandwidth is later changed to 500 Kbps, the AutoQoS -- VoIP feature will not use the lower bandwidth. The AutoQoS -- VoIP feature retains the higher bandwidth and continues to use the generated configurations for high-speed interfaces. To force the AutoQoS -- VoIP feature to use the lower bandwidth (and thus generate configurations for the low-speed interfaces), use the no auto qos voip command to remove the AutoQoS -- VoIP feature and then reconfigure the feature. Fragmentation for Frame Relay Networks
To solve this potential problem, choose one of the following:
For example, if the AutoQoS -- VoIP feature is configured on a Frame Relay DLCI with 128 Kbps, the fragment size configured by the AutoQoS -- VoIP feature will be 160 bytes. The size of the G.711 VoIP packet will be 160 bytes, minus the bytes in the packet headers for the layers. The workaround is to either change the fragment size from 160 bytes to 220 bytes or change the size of the G.711 VoIP packet from 160 bytes to 80 bytes. Signaling Protocols
Configurations for the Interface Configurations Policy Maps Class Maps and ACLsThe AutoQoS -- VoIP feature automatically creates configurations that are then used for the interface configurations, policy maps, class maps, and ACLs. The interface configurations, policy maps, class maps, and ACLs are created to classify VoIP packets and to provide the appropriate QoS treatment for the network traffic. This feature also creates interface (or PVC)-specific configurations. These interface (or PVC)-specific configurations are created according to the interface type and the link speed.
How to Configure the AutoQoS - VoIP FeatureEnabling the AutoQoS - VoIP FeatureBefore You Begin
SUMMARY STEPS
Before using the auto qos command at an interface or an ATM PVC, ensure that the following prerequisites have been met:
DETAILED STEPS FAQs and Troubleshooting TipsBelow are answers to frequently asked questions (FAQs) and tips for troubleshooting situations that you may encounter when configuring or using the AutoQoS -- VoIP feature. Why canât I configure the AutoQoS - VoIP feature?
Why isnât the AutoQoS - VoIP feature supported on my router?
Why are some of my QoS configurations still present after I disable the AutoQoS - VoIP feature?
Why did my low-speed network link go down when I enabled the AutoQoS - VoIP feature?
Why canât I establish an end-to-end connection on the Frame Relay link?
What to Do NextIf the interface configurations, policy maps, class maps, and ACLs created (on the basis of the configurations created by the AutoQoS - VoIP feature) do not meet the needs of your network, the interface configurations, policy maps, class maps, and ACLs can be modified using the appropriate Cisco IOS commands.
Verifying the ConfigurationSUMMARY STEPS
DETAILED STEPS
Configuration Examples for AutoQoS - VoIP
Examples Configuring the AutoQoS - VoIP FeatureWhen the auto qos voip command is used to configure the AutoQoS -- VoIP feature, configurations are generated. These configurations are then used to create interface configurations, policy maps, class maps, and aCLs. This section contains the following examples of configuring the AutoQoS -- VoIP feature on the interfaces, PVCs, and links. Configuring the AutoQoS - VoIP Feature on a High-Speed Serial Interface ExampleIn this example, the AutoQoS -- VoIP feature is configured on the high-speed serial interface s1/2. Router> enable Router# configure terminal
Router(config)# interface s1/2
Router(config-if)# bandwidth 1540
Router(config-if)# auto qos voip
Router(config-if)#
exit
Configuring the AutoQoS - VoIP Feature on a Low-Speed Serial Interface ExampleIn this example, the AutoQoS -- VoIP feature is configured on the low-speed serial interface s1/3.
Router# configure terminal
Router(config)# interface s1/3
Router(config-if)# bandwidth 512
Router(config-if)# ip address 10.10.100.1 255.255.255.0
Router(config-if# auto qos voip
Router(config-if)#
exit
Configuring the AutoQoS - VoIP Feature on High-Speed Frame Relay Interfaces ExampleIn this example, the AutoQoS -- VoIP feature is configured on the high-speed serial point-to-point Frame Relay subinterface s4/1.2. Router> enable Router# configure terminal
Router(config)# interface s4/1.2 point-to-point
Router(config-if)# bandwidth 1540
Router(config-if)# frame-relay interface-dlci 100
Router(config-fr-dlci)# auto qos voip
Router(config-if)#
exit
Configuring the AutoQoS - VoIP Feature on Low-Speed Frame Relay Interfaces ExampleIn this example, the AutoQoS -- VoIP feature is configured on the low-speed point-to-point Frame Relay subinterface s4/2.1.
Router# configure terminal
Router(config)# interface s4/2.1 point-to-point
Router(config-if)# bandwidth 512
Router(config-if)# ip address 10.10.100.1 255.255.255.0
Router(config-if)# frame-relay interface-dlci 100
Router(config-fr-dlci)# auto qos voip
Router(config-if)#
exit
Configuring the AutoQoS - VoIP Feature on a High-Speed ATM PVC ExampleIn this example, the AutoQoS -- VoIP feature is configured on the high-speed point-to-point ATM PVC ATM5/0.1.
Router# configure terminal
Router(config)# interface ATM5/0.1 point-to-point
Router(config-if)# pvc 1/32
Router(config-if)# vbr-nrt 1540 1540
Router(config-if)# auto qos voip
Router(config-if)#
exit
Configuring the AutoQoS - VoIP Feature on a Low-Speed ATM PVC ExampleIn this example, the AutoQoS -- VoIP feature is configured on a low-speed point-to-point ATM PVC ATM5/0.2.
Router# configure terminal
Router(config)# interface ATM5/0.2 point-to-point
Router(config-if)# ip address 10.10.100.1 255.255.255.0
Router(config-if)# pvc 1/32
Router(config-if)# vbr-nrt 512 512
Router(config-if)# auto qos voip
Router(config-if)#
exit
Configuring the AutoQoS - VoIP Feature for Frame Relay-to-ATM Interworking ExampleIn this example, the AutoQoS -- VoIP feature is configured for Frame Relay-to-ATM Interworking. The AutoQoS -- VoIP feature is configured on the serial point-to-point subinterface s1/3.1.
Router# configure terminal
Router(config)# interface s1/3.1 point-to-point
Router(config-if)# bandwidth 512
Router(config-if)# ip address 10.10.100.1 255.255.255.0
Router(config-if)# frame-relay interface-dlci 100
Router(config-if)# auto qos voip fr-atm
Router(config-if)#
exit
In this configuration, the optional fr-atm keyword is used to enable the AutoQoS -- VoIP feature for the Frame Relay-to-ATM Interworking.
Examples Verifying the AutoQoS - VoIP Feature ConfigurationWhen the auto qos voip command is used to configure the AutoQoS -- VoIP feature, configurations are generated. These configurations are then used to create interface configurations, policy maps, class maps, and ACLs. The show auto qos interface command can be used to verify the contents of the interface configurations, policy maps, class maps, and ACLs. This section contains the following sample output of the show auto qos interface command for interfaces, PVCs, and links.
Sample show auto qos interface Command Output for a High-Speed Serial InterfaceThe following is sample output of the show auto qoscommand for a high-speed serial interface:
Router# show auto qos interface s6/0
Serial6/0 -
!
interface Serial6/0
service-policy output AutoQoS-Policy-UnTrust
Sample show auto qos interface Command Output for a Low-Speed Serial InterfaceThe following is sample output of the show auto qos interfacecommand for a low-speed serial interface:
Router# show auto qos interface s6/0
Serial6/0 -
!
interface Serial6/0
no ip address
encapsulation ppp
no fair-queue
ppp multilink
multilink-group 2001100126
!
interface Multilink2001100126
bandwidth 512
ip address 10.10.100.1 255.255.255.0
service-policy output AutoQoS-Policy-UnTrust
ppp multilink
ppp multilink fragment-delay 10
ppp multilink interleave
ip rtp header-compression iphc-format
Sample show auto qos Interface Command Output for a High-Speed Frame Relay InterfaceThe following is sample output of the show auto qoscommand for a high-speed Frame Relay interface:
Router# show auto qos interface s6/1.1
Serial6/1.1: DLCI 100 -
!
interface Serial6/1
frame-relay traffic-shaping
!
interface Serial6/1.1 point-to-point
frame-relay interface-dlci 100
class AutoQoS-VoIP-FR-Serial6/1-100
!
map-class frame-relay AutoQoS-VoIP-FR-Serial6/1-100
frame-relay cir 1540000
frame-relay bc 15400
frame-relay be 0
frame-relay mincir 1540000
service-policy output AutoQoS-Policy-UnTrust
Sample show auto qos interface Command Output for a Low-Speed Frame Relay InterfaceThe following is sample output of the show auto qoscommand for a low-speed Frame Relay interface:
Router# show auto qos interface s6/1.1
Serial6/1.1: DLCI 100 -
!
interface Serial6/1
frame-relay traffic-shaping
!
interface Serial6/1.1 point-to-point
frame-relay interface-dlci 100
class AutoQoS-VoIP-FR-Serial6/1-100
frame-relay ip rtp header-compression
!
map-class frame-relay AutoQoS-VoIP-FR-Serial6/1-100
frame-relay cir 512000
frame-relay bc 5120
frame-relay be 0
frame-relay mincir 512000
service-policy output AutoQoS-Policy-UnTrust
frame-relay fragment 640
Sample show auto qos interface Command Output for a High-Speed ATM PVCThe following is sample output of the show auto qoscommand for a high-speed ATM PVC:
Router# show auto qos interface a2/0.1
ATM2/0.1: PVC 1/100 -
!
interface ATM2/0.1 point-to-point
pvc 1/100
tx-ring-limit 3
service-policy output AutoQoS-Policy-UnTrust
Sample show auto qos interface Command Output for a Low-Speed ATM PVCThe following is sample output of the show auto qoscommand for a low-speed ATM PVC:
Router# show auto qos interface a2/0.1
ATM2/0.1: PVC 1/100 -
!
interface ATM2/0.1 point-to-point
pvc 1/100
tx-ring-limit 3
encapsulation aal5mux ppp Virtual-Template200
!
interface Virtual-Template200
bandwidth 512
ip address 10.10.100.1 255.255.255.0
service-policy output AutoQoS-Policy-UnTrust
ppp multilink
ppp multilink fragment-delay 10
ppp multilink interleave
Sample show auto qos interface Command Output for Frame Relay-to-ATM Interworking LinksThe following is sample output of the show auto qoscommand for Frame Relay-to-ATM Interworking links:
Router# show auto qos interface s6/1.1
Serial6/1.1: DLCI 100 -
!
interface Serial6/1
frame-relay traffic-shaping
!
interface Serial6/1.1 point-to-point
frame-relay interface-dlci 100 ppp Virtual-Template200
class AutoQoS-VoIP-FR-Serial6/1-100
!
interface Virtual-Template200
bandwidth 512
ip address 10.10.100.1 255.255.0.0
service-policy output AutoQoS-Policy-UnTrust
ppp multilink
ppp multilink fragment-delay 10
ppp multilink interleave
!
map-class frame-relay AutoQoS-VoIP-FR-Serial6/1-100
frame-relay cir 512000
frame-relay bc 5120
frame-relay be 0
frame-relay mincir 512000
Additional ReferencesUse Cisco Feature Navigator to find information about platform support and software image support. Cisco Feature Navigator enables you to determine which software images support a specific software release, feature set, or platform. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn . An account on Cisco.com is not required.
Related Documents
MIBs
Technical Assistance
Feature Information for AutoQoS - VoIPThe following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature. Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.
Cisco and the Cisco Logo are trademarks of Cisco Systems, Inc. and/or its affiliates in the U.S. and other countries. A listing of Cisco's trademarks can be found at www.cisco.com/go/trademarks. Third party trademarks mentioned are the property of their respective owners. The use of the word partner does not imply a partnership relationship between Cisco and any other company. (1005R) Any Internet Protocol (IP) addresses and phone numbers used in this document are not intended to be actual addresses and phone numbers. Any examples, command display output, network topology diagrams, and other figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses or phone numbers in illustrative content is unintentional and coincidental. |
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