3com 2948-SFP Plus Betriebsanweisung

C

HAPTER 13: 

C

ONFIGURING 

Q

UALITY 

O

F 

S

ERVICE

Voice VLAN allows network administrators to enhance the VoIP service 
by configuring ports to carry IP voice traffic from IP phones on a specific 
VLAN. VoIP traffic has a preconfigured OUI prefix in the source MAC 
address. Network Administrators can configure VLANs on which voice 
IP traffic is forwarded. Non-VoIP traffic is dropped from the Voice VLAN 
in auto Voice VLAN secure mode. Voice VLAN also provides QoS to VoIP, 
ensuring that the quality of voice does not deteriorate if the IP traffic is 
received unevenly. The system supports one Voice VLAN.

There are two operational modes for IP Phones:

 

   IP phones are configured with VLAN-mode as enabled, ensuring  

 

 

that tagged packets are used for all communications.

 

   If the IP phone’s VLAN-mode is disabled, the phone uses  

 

 

untagged packets. The phone uses untagged packets while  

 

 

retrieving the initial IP address through DHCP. The phone  

 

 

eventually use the Voice VLAN and start sending tagged  

 

 

packets.

This section contains the following topics:

  Viewing Voice VLANs

  Defining Voice VLAN

  Defining Voice VLAN Port Settings

  Viewing Voice VLAN Port Definitions

  Viewing the OUI Summaries

  Modifying OUI Definitions