Transcript PT6 Building a VoIP Network (Part3)

Packet Tracer 6
Building a VoIP Network (Part 3)
Eric Kwok
CCIE #43698 (R&S)
Technical Manager, APAC Region
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• Why do we need Voice VLAN?
• Access port or trunk port?
• Tagged or not tagged?
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• 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
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Access vlan 20
(voice)
Access vlan 10
(data)
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CDP
Native VLAN 10
Voice VLAN 20
PoE Power
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• SW(config-if)# switchport mod access
• SW(config-if)# switchport access vlan 10
• SW(config-if)# switchport voice vlan 20
PCP (Priority or CoS)
D
Special 802.1Q trunk
through CDP
20
PC
SW
V
D
Fa0/1
Data vlan 10
Voice vlan 20
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SW#sh int switchport
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
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
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• 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)
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S.MAC
D.MAC
Type/
Length
S.MAC
D.MAC
802.1Q
Tag
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Payload
Type/
Length
FCS
Payload
TPCI
PCP
0x8100
Priority
0-7
FCS
DEI
CFI
VLAN ID
VLAN
0-4095
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Packet capture
SPAN Port
Cisco 891W
4 Ports PoE
PoE Ports
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Packet capture
Phone sending out CDP
Cisco 7970
Request 10.25W PoE power
Max Power Consumption
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CDP from Router
Cisco 891 Router
Native VLAN for Data (untagged)
Voice VLAN (tagged)
Available PoE Power
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Voice VLAN 20
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Packet capture
Voice Frame VLAN 20
• RTP , Pri 5
• SKINNY, Pri 0, 3
7961 Data Frame untagged
Native VLAN
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7961 Data Frame untagged
Native VLAN
Data Frame VLAN 10, Pri 0
7970 Data Frame tagged
VLAN 10, Pri 0
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PCP (Priority or CoS)
D
20
V
D
20
V
10
D
Special 802.1Q trunk
through CDP
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• 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
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