Net To Net Technologies SIA2410R User Manual
Net To Net Technologies
46
Per Port Method
General priority can be specified on a per port basis. In this type of priority all
traffic from the specified input port is considered high priority in the
destination queue. This can be useful in IP phone applications mixed with
other data types of traffic where the IP phone connects to a specific port. The
IP phone traffic would be high priority (outbound) to the wide area network.
The inbound traffic to the IP phone is all of the same priority to the IP phone.
802.1p Method
This method works well when used with ports that have mixed data and
media flows. The inbound port examines the priority field in the tag and
determines the high or low priority. Priority profiles are setup in the Priority
Classification Control in the EEPROM.
The Default QoS method is 802.1p in the SIA2410R. And the Default mapping
between 802.1p priority and priority queue is as follows;
802.1p User Priority 0 ~ 3
Low priority queue
802.1p User Priority 4 ~ 7
High priority queue
IPv4 DSCP Method
This is another per frame way of determining outbound priority. The DSCP
(Differentiated Services Code Point – RFC#2474) method uses the TOS field
in the IP header to determine high and low priority on a per code point basis.
Each fully decoded code point can have either a high or low priority. A larger
spectrum of priority flows can be defined with this larger code space. More
specific to implementation, the most significant 6 bits of the TOS field are fully
decoded into 64 possibilities, and the singular code that results is compared
against the corresponding bit in the DSCP register. If the register bit is a 1,
the priority is high and if 0, the priority is low.
