3Com 3CNJ220-CRM, Руководство пользователя

Страница: 50 / 82

46 C
HAPTER
4: U
SING THE
C
ENTRAL
C
ONFIGURATION
M
ANAGER
Priority & VLAN
Configuration
11 Click the Priority & VLAN Configuration tab along the top of the Device
Configuration window to view these settings:
Port Based Settings
12 To change the Port Based Settings, first select the Port’s tab you want to make the
changes to.
13 To change the Look-up Scheme from the default of Use Both, click the box and
select an option from the drop list.
Both the Use IEEE 802.1p Traffic Class Field and Use IP TOS, DiffServ fields look-up
schemes examine Ethernet packets to determine their prioritization. The former
looks at one portion of the packet, effectively making it a Layer 2 tool. The latter
looks at a different part of the packet, effectively making it a Layer 3 tool.
The Look-up Scheme is part of the prioritization of Ethernet packets. Prioritization
determines which packets clear the buffer first. If you didn’t care about the
prioritization of packets, you would choose None. If you wanted to prioritize voice
packets on Port 1, for example, you would choose another option.