AutoQoS VOIP on Routers
Meant for use on LAN ports. The command to enable AutoQoS on interfaces is auto qos voip [trust] at the interface or frame relay DLCI level. You'll also need to have the bandwidth command in place before enabling AutoQoS; changing it later won't affect the QoS setup so you'd need to rerun AutoQoS in that instance.
When you enable AutoQoS on a frame relay interface slower than 768kbps, it also enables compression and fragmentation. Regardless of the speed, a router will still perform the standard config for traffic shaping and apply the policy automatically.
On serial interfaces that aren't frame relay which are slower than 768kbps, AutoQoS changes the encapsulation to PPP and enables the features link fragmentation and interleaving (LFI). Interfaces that are faster will retain their original encapsulation.
When the trust keyword is used, the router groups traffic (via class maps) based on DSCP values. Those DSCP values are already present in packets and are assumed to be set by a trusted device(s). Without the trust keyword, the router creates class maps for voice and video traffic as well as call control ports. Those types are mapped into classes and any traffic not matching them is marked with DSCP value 0.
Verifying AutoQoS for VOIP
show auto qos displays QoS commands for an interface
show mls qos shows queuing and mappings for CoS-DSCP and vice versa
show policy-map interface displays how the policy maps are assigned to interfaces and details of each
AutoQoS for the Enterprise
Supported on Cisco routers; the main difference between this and AutoQoS VOIP is that Enterprise supports other applications and is meant to be used for WAN links. May be configured on Frame and ATM sub-interfaces if they are point to point links only. This has two steps- discovering traffic and a resulting QoS config.
Traffic discovery takes place on interfaces, so the command is run at the PVC, DLCI, or interface config level. CEF must be on, QoS should NOT be already in place on the interface, and you should have the bandwidth command specified. The command used to enable discovery is auto discovery qos [trust] and the trust keyword is used (as stated before) to accept existing QoS markings on traffic.
Activating traffic discovery enables NBAR (for that interface). Ten classes are created and traffic is classified into one of the ten. Default classification with the trust keyword is as follows (sample traffic is listed for each)-
Class DSCP/PHB Value Traffic Examples
Routing CS 6 EIGRP, OSPF
VOIP EF (DSCP 46) RTP Voice Media
Interactive Video AF 41 RTP Video Media
Streaming Video CS4 RealAudio, Netshow
Control Signaling CS3 H323, SIP
Transactional AF21 SAP, Citrix, Telnet, SSH
Bulk AF11 FTP, POP3, SMTP, Exchange
Scavenger CS1 Peer to peer applications
Management CS2 SNMP, Syslog, DNS
Best Effort All others All other traffic
Disabling AutoQoS for an interface disables NBAR on there as well. The related command is no auto discovery qos. To validate that QoS is enabled, use the same commands as for AutoQoS VOIP. The only new command is show auto discovery qos, which displays NBAR statistics.
Meant for use on LAN ports. The command to enable AutoQoS on interfaces is auto qos voip [trust] at the interface or frame relay DLCI level. You'll also need to have the bandwidth command in place before enabling AutoQoS; changing it later won't affect the QoS setup so you'd need to rerun AutoQoS in that instance.
When you enable AutoQoS on a frame relay interface slower than 768kbps, it also enables compression and fragmentation. Regardless of the speed, a router will still perform the standard config for traffic shaping and apply the policy automatically.
On serial interfaces that aren't frame relay which are slower than 768kbps, AutoQoS changes the encapsulation to PPP and enables the features link fragmentation and interleaving (LFI). Interfaces that are faster will retain their original encapsulation.
When the trust keyword is used, the router groups traffic (via class maps) based on DSCP values. Those DSCP values are already present in packets and are assumed to be set by a trusted device(s). Without the trust keyword, the router creates class maps for voice and video traffic as well as call control ports. Those types are mapped into classes and any traffic not matching them is marked with DSCP value 0.
Verifying AutoQoS for VOIP
show auto qos displays QoS commands for an interface
show mls qos shows queuing and mappings for CoS-DSCP and vice versa
show policy-map interface displays how the policy maps are assigned to interfaces and details of each
AutoQoS for the Enterprise
Supported on Cisco routers; the main difference between this and AutoQoS VOIP is that Enterprise supports other applications and is meant to be used for WAN links. May be configured on Frame and ATM sub-interfaces if they are point to point links only. This has two steps- discovering traffic and a resulting QoS config.
Traffic discovery takes place on interfaces, so the command is run at the PVC, DLCI, or interface config level. CEF must be on, QoS should NOT be already in place on the interface, and you should have the bandwidth command specified. The command used to enable discovery is auto discovery qos [trust] and the trust keyword is used (as stated before) to accept existing QoS markings on traffic.
Activating traffic discovery enables NBAR (for that interface). Ten classes are created and traffic is classified into one of the ten. Default classification with the trust keyword is as follows (sample traffic is listed for each)-
Class DSCP/PHB Value Traffic Examples
Routing CS 6 EIGRP, OSPF
VOIP EF (DSCP 46) RTP Voice Media
Interactive Video AF 41 RTP Video Media
Streaming Video CS4 RealAudio, Netshow
Control Signaling CS3 H323, SIP
Transactional AF21 SAP, Citrix, Telnet, SSH
Bulk AF11 FTP, POP3, SMTP, Exchange
Scavenger CS1 Peer to peer applications
Management CS2 SNMP, Syslog, DNS
Best Effort All others All other traffic
Disabling AutoQoS for an interface disables NBAR on there as well. The related command is no auto discovery qos. To validate that QoS is enabled, use the same commands as for AutoQoS VOIP. The only new command is show auto discovery qos, which displays NBAR statistics.
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