Packet Tracer 6 Building a VoIP Network (Part 3) Eric Kwok CCIE #43698 (R&S) Technical Manager, APAC Region

Session 3 Why do we need Voice VLAN? Access port or trunk port? Tagged or not tagged?

Why? Performance (Broadcast domain) Manageability (apply policy, QoS, logical group, addressing) Independent of Physical Topology (connect phone to any vlan access port) Security (boundary between data and voice packet) Access vlan 10 Voice vlan 20 Access vlan 20 (voice) Access vlan 10 (data)

Phone boot up CDP Native VLAN 10 Voice VLAN 20 PoE Power

Special 802.1Q trunk through CDP Voice VLAN SW(config-if)# switchport mod access SW(config-if)# switchport access vlan 10 SW(config-if)# switchport voice vlan 20 PCP (Priority or CoS) Special 802.1Q trunk through CDP D V 20 D PC SW Fa0/1 Data vlan 10 Voice vlan 20

SW#sh int switchport Name: Fa0/1 Switchport: Enabled Administrative Mode: static access Operational Mode: static access Administrative Trunking Encapsulation: dot1q Operational Trunking Encapsulation: native Negotiation of Trunking: Off Access Mode VLAN: 10 (data) Trunking Native Mode VLAN: 1 (default) Voice VLAN: 20 Administrative private-vlan host-association: none Administrative private-vlan mapping: none Administrative private-vlan trunk native VLAN: none Administrative private-vlan trunk encapsulation: dot1q Administrative private-vlan trunk normal VLANs: none Administrative private-vlan trunk private VLANs: none Operational private-vlan: none Trunking VLANs Enabled: All Pruning VLANs Enabled: 2-1001 Capture Mode Disabled Capture VLANs Allowed: ALL Protected: false Unknown unicast blocked: disabled Unknown multicast blocked: disabled Appliance trust: none SW#sh int switchport Name: Fa0/6 Switchport: Enabled Administrative Mode: dynamic auto Operational Mode: down Administrative Trunking Encapsulation: dot1q Operational Trunking Encapsulation: native Negotiation of Trunking: On Access Mode VLAN: 1 (default) Trunking Native Mode VLAN: 1 (default) Voice VLAN: none Administrative private-vlan host-association: none Administrative private-vlan mapping: none Administrative private-vlan trunk native VLAN: none Administrative private-vlan trunk encapsulation: dot1q Administrative private-vlan trunk normal VLANs: none Administrative private-vlan trunk private VLANs: none Operational private-vlan: none Trunking VLANs Enabled: All Pruning VLANs Enabled: 2-1001 Capture Mode Disabled Capture VLANs Allowed: ALL Protected: false Unknown unicast blocked: disabled Unknown multicast blocked: disabled

CoS Ethernet Frame to include QoS No field to specific the priority of the frame 802.1p task group to work on the traffic classes Used in 802.1Q tag (3 bits PCP)

CoS in Voice Frame TPCI PCP DEI CFI VLAN ID 0x8100 Priority 0-7 VLAN S.MAC D.MAC Type/ Length Payload FCS S.MAC D.MAC 802.1Q Tag Type/ Length Payload FCS TPCI PCP DEI CFI VLAN ID 0x8100 Priority 0-7 VLAN 0-4095

Packet capture Lab Setup SPAN Port Cisco 891W 4 Ports PoE PoE Ports

Phone CDP Phone sending out CDP Cisco 7970 Request 10.25W PoE power Packet capture Phone CDP Phone sending out CDP Cisco 7970 Request 10.25W PoE power Max Power Consumption

Router (integrated Switch) CDP CDP from Router Cisco 891 Router Native VLAN for Data (untagged) Voice VLAN (tagged) Available PoE Power

Voice VLAN 20

Priority in VLAN Tag (Voice and Data Frame) Packet capture Voice Frame VLAN 20 RTP , Pri 5 SKINNY, Pri 0, 3 7961 Data Frame untagged Native VLAN

7961 Data Frame untagged Native VLAN Data Frame VLAN 10, Pri 0 7970 Data Frame tagged VLAN 10, Pri 0

Let‘s go to Packet Tracer PCP (Priority or CoS) V 20 D V 20 D 20 V 10 D D Special 802.1Q trunk through CDP

Session 3 Summary Why do we need Voice VLAN? Both data vlan and voice vlan in single port Security (diff vlan, policy) and performance (broadcast domain) Access port or trunk port? Special trunk or access port which can handle 802.1Q tag Tagged or not tagged? Voice is tagged with CoS set Data could be tagged or not tagged depends on the phone model Notes: Port security, max 2 addresses