### Configure Basic VoIP
CAT3550(config)#interface fas 0/3
CAT3550(config-if)#switchport mode access
CAT3550(config-if)#switchport access vlan 200
CAT3550(config-if)#switchport voice vlan 100
CAT3550(config-if)#mls qos trust device cisco-phone
CAT3550(config-if)#auto qos voip cisco-phone
CAT3550(config-if)#do show run interface fas0/3
!
interface FastEthernet0/3
switchport access 200
switchport mode access
switchport voice vlan 100
duplex full
speed 100
mls qos trust device cisco-phone
mls qos trust cos
auto qos voip cisco-phone
wrr-queue bandwidth 10 20 70 1
wrr-queue min-reserve 1 5
wrr-queue min-reserve 2 6
wrr-queue min-reserve 3 7
wrr-queue min-reserve 4 8
wrr-queue cos-map 1 0 1
wrr-queue cos-map 2 2 4
wrr-queue cos-map 3 3 6 7
wrr-queue cos-map 4 5
priority-queue out
spanning-tree portfast
end
### QoS pre-classification
With VPN traffic, the only thing we have to work with is the ToS byte of the original packet, which is automatically copied to the tunnel header (IPsec transport mode, IPsec tunnel mode and GRE).
But features like NBAR are broken.
Cisco IOS includes a feature called QoS pre-classification that can be enabled on VPN endpoint routers that keep the original traffic in memory until the egress QoS actions is taken:
- GRE and IPIP:
interface tunnel- L2F and L2TP:
interface virtual-template- IPsec:
crypto map### AutoQoS
Is a macro that helps automate class-based Qos configuration using best practice recommendations.
There are two flavors: AutoQoS for VoIP and for the Enterprise.
To verify AutoQoS configuration use:
-
show auto qos-
show mls qos-
show policy-map interface-
show auto discovery qos### AutoQoS for VoIP
Provides QoS both global and interface configuration for voice and video applications.
Is supported on routers and switches.
When enabled on access ports, AutoQoS uses CDP to detect the presence of a Cisco phone or softphone:
-
auto qos voip {cisco-phone | cisco-softphone}- Normal traffic is treated as best effort.
- For phone traffic, the switch trusts the QoS markings it receives.
When enabled on a trunk or uplink, it trusts the CoS or DSCP values received:
-
auto qos voip trust### AutoQoS for the Enterprise
Provides QoS both global and interface configuration for voice, video and other network applications.
Is supported on routers.
The command to enable traffic discovery is
auto discovery qos [trust] and is configured at the interface, DLCI or PVC level.Use the
trust keyword if you trust the traffic already marked because AutoQoS policies will use those markings during the configuration stage.The router will classify the traffic collected into one of ten classes:
- Routing: CS6 - EIGRP, OSPF
- VoIP: EF - RTP voice media
- Interactive video: AF41 - RTP video media
- Streaming video: CS4 - Real audio, Netshow
- Control: CS3 - RTCP, H323, SIP
- Transactional: AF21 - SAP, Citrix, Telnet, SSH
- Bulk: AF11 - FTP, SMTP, POP3, Exchange
- Scavenger: CS1 - P2P applications
- Management: CS2 - SNMP, Syslog, DHCP, DNS
- Best effort: All others - All others.
Finally, configure the
auto qos command and disable the traffic discovery.
