© 2006 Cisco Systems, Inc. All rights reserved. BCMSN v3.07-1 Configuring Campus Switches to Support Voice Accommodating Voice Traffic on Campus Switches. - презентация

1 © 2006 Cisco Systems, Inc. All rights reserved. BCMSN v Configuring Campus Switches to Support Voice Accommodating Voice Traffic on Campus Switches

2 © 2006 Cisco Systems, Inc. All rights reserved. BCMSN v QoS and Voice Traffic in the Campus Model

3 © 2006 Cisco Systems, Inc. All rights reserved. BCMSN v LAN-Based Classification and Marking

4 © 2006 Cisco Systems, Inc. All rights reserved. BCMSN v Layer 2 Marking: 802.1p, CoS 802.1p User Priority field is also called class of service (CoS). Different types of traffic are assigned different CoS values. CoS 6 and 7 are reserved for network use.

5 © 2006 Cisco Systems, Inc. All rights reserved. BCMSN v Layer 3 Marking: IP Precedence, DSCP IPv4 –Three most significant bits of ToS byte are called IP precedence. –Other bits are unused. DiffServ –Six most significant bits of ToS byte are called DiffServ Code Point (DSCP). –DSCP is backward compatible with IP precedence. –Remaining two bits are used for flow control.

6 © 2006 Cisco Systems, Inc. All rights reserved. BCMSN v Classification Tools: Trust Boundaries A device is trusted if it correctly classifies packets. For scalability, classification should be done as close to the edge as possible. The outermost trusted devices represent the trust boundary. and are optimal; is acceptable (if the access switch cannot perform classification). 123

7 © 2006 Cisco Systems, Inc. All rights reserved. BCMSN v Configuring a Switch for Attachment of a Cisco IP Phone Voice traffic tagged for voice VLAN Data VLAN traffic from PC can be –Untrusted –Trusted –Set to a specific value

8 © 2006 Cisco Systems, Inc. All rights reserved. BCMSN v Basic Switch Commands to Support Attachment of a Cisco IP Phone Configure voice VLAN switchport voice vlan 110 Configure trust and CoS options mls qos trust cos mls qos trust device cisco-phone mls qos extend trust switchport priority extend cos cos_value Verify configuration show interfaces fa 0/4 switchport show mls qos interface fa 0/4

9 © 2006 Cisco Systems, Inc. All rights reserved. BCMSN v Configuration Example Switch(config)# mls qos Switch(config)# interface fastethernet 0/4 Switch(config-if)# switchport voice vlan 110 Switch(config-if)# switchport access vlan 10 Switch(config-if)# mls qos trust cos Switch(config-if)# mls qos trust device cisco-phone Switch(config-if)# ctrl-Z Switch# show interfaces fastethernet 0/4 Switch# show mls qos interface fastethernet 0/4 FastEthernet0/4 trust state: trust cos trust mode: trust cos COS override: dis default COS: 0 pass-through: none trust device: cisco-phone

10 © 2006 Cisco Systems, Inc. All rights reserved. BCMSN v Cisco AutoQoS One command per interface to enable and configure QoS

11 © 2006 Cisco Systems, Inc. All rights reserved. BCMSN v Cisco AutoQoS (Cont.) Application classification –Automatically discovers applications and provides appropriate QoS treatment Policy generation –Automatically generates initial and ongoing QoS policies Configuration –Provides high-level business knobs, and multi-device/domain automation for QoS Monitoring and reporting –Generates intelligent, automatic alerts and summary reports Consistency –Enables automatic, seamless interoperability among all QoS features and parameters across a network topology–LAN, MAN, and WAN

12 © 2006 Cisco Systems, Inc. All rights reserved. BCMSN v Configuring Cisco AutoQoS Single command at the interface level configures interface and global QoS. –Support for Cisco IP Phone and Cisco IP Communicator. Support for Cisco IP Communicator currently exists only on the Cisco Catalyst –Trust boundary is disabled when Cisco IP Phone is moved. –Buffer allocation and egress queuing are dependent on interface type (Gigabit Ethernet/Fast Ethernet). Supported on static, dynamic-access, voice VLAN access, and trunk ports. CDP must be enabled for Cisco AutoQoS to function properly.

13 © 2006 Cisco Systems, Inc. All rights reserved. BCMSN v Configuring Cisco AutoQoS: Cisco Catalyst OS Console>(enable)set qos autoqos QoS is enabled All ingress and egress QoS scheduling parameters configured on all ports.CoS to DSCP, DSCP to COS, IP Precedence to DSCP and policed dscp maps configured. Global QoS configured, port specific autoqos recommended: set port qos autoqos trust set port qos autoqos voip set qos autoqos Console> (enable) Global configuration command. All the global QoS settings are applied to all ports in the switch. Prompt displays the CLI for the port-based automatic QoS commands currently supported.

14 © 2006 Cisco Systems, Inc. All rights reserved. BCMSN v Configuring Cisco AutoQoS: Cisco Catalyst OS (Cont.) trust dscp and trust cos are automatic QoS keywords used for ports requiring a trust all type of solution. trust dscp should be used only on ports that connect to other switches or known servers because the port will be trusting all inbound traffic marking Layer 3 (DSCP). trust cos should only be used on ports connecting other switches or known servers because the port trusts all inbound traffic marking in Layer 2 (CoS). The trusted boundary feature is disabled and no QoS policing is configured on these types of ports. set port qos autoqos trust [cos|dscp] Console> (enable)

15 © 2006 Cisco Systems, Inc. All rights reserved. BCMSN v Configuring Cisco AutoQoS: Cisco Catalyst OS (Cont.) set port qos autoqos voip [ciscosoftphone | ciscoipphone] [trust] Console> (enable) ciscosoftphone The trusted boundary feature must be disabled for Cisco IP Communicator ports. QoS settings must be configured to trust the Layer 3 markings of the traffic that enters the port. Only available on Cisco Catalyst ciscoipphone The port is set up to use trust-cos as well as to enable the trusted boundary feature. Combined with the global automatic QoS command, all settings are configured on the switch to properly handle the signaling and voice bearer and PC data entering and leaving the port. CDP must be enabled for the ciscoipphone, QoS configuration. Note: IP Communicator is a softphone, which is an application running on a PC emulating a handset.

16 © 2006 Cisco Systems, Inc. All rights reserved. BCMSN v Configuring Cisco AutoQoS: Native OS auto qos voip trust Switch(config-if)# The uplink interface is connected to a trusted switch or router, and the VoIP classification in the ingress packet is trusted. auto qos voip cisco-phone Switch(config-if)# Automatically enables the trusted boundary feature, which uses the CDP to detect the presence or absence of a Cisco IP Phone. If the interface is connected to a Cisco IP Phone, the QoS labels of incoming packets are trusted only when the Cisco IP Phone is detected.

17 © 2006 Cisco Systems, Inc. All rights reserved. BCMSN v Monitoring Cisco AutoQoS show auto qos [interface interface-id] Switch# Switch#show auto qos Initial configuration applied by AutoQoS: wrr-queue bandwidth no wrr-queue cos-map wrr-queue cos wrr-queue cos wrr-queue cos 4 5 mls qos map cos-dscp ! interface FastEthernet0/3 mls qos trust device cisco-phone mls qos trust cos Displays the Cisco AutoQoS configuration that was initially applied Does not display any user changes to the configuration that might be in effect

18 © 2006 Cisco Systems, Inc. All rights reserved. BCMSN v Automation with Cisco AutoQoS DiffServ Function Cisco IOS/Catalyst Software QoS Feature Behavior ClassificationNBAR DSCP, Port Classifies VoIP based on packet attributes or port trust MarkingClass-based markingSets Layer 3/Layer 2 attributes to categorize packets into a class Congestion Management Percentage-based LLQ, WRR Provides EF treatment to voice and best-effort treatment to data

19 © 2006 Cisco Systems, Inc. All rights reserved. BCMSN v Summary QoS can reduce latency in a campus network when VoIP is configured. QoS trust boundaries allow for LAN-based classification and marking. LAN-based classification and marking can be accomplished by a Cisco Catalyst workgroup switch. Configuration is necessary to implement trust boundaries when VoIP is incorporated. Specific commands are required when configuring QoS trust boundaries on a Cisco Catalyst switch. Cisco AutoQoS is a simple way to implement a trust boundary for VoIP. Configuration of Cisco AutoQoS is simple and supported on Cisco Catalyst switches.

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