H3C Technologies H3C S10500 Series Switches - Manual (Page 65)

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Priority marking configuration
Priority marking sets the priority fields or flag bits of packets to modify the priority of traffic. For example,
you can use priority marking to set IP precedence or DSCP for a class of IP traffic to change its
transmission priority in the network.
Priority marking can be used together with priority mapping. For more information about priority
mapping, see “ Configuring priority mapping .”
Color-based priority marking
The SE, EA, and EB cards for the S10500 support color-based priority marking.
Coloring a packet
The switch colors a packet to indicate its transmission priority after evaluating the status of processing
resources and the priority of the packet.
The switch can color a packet by using one of the following approaches:
• Uses the token bucket mechanism (bucket C and bucket E) of traffic policing:
{
If bucket C has enough tokens, the packet is colored green.
{
If bucket C does not have enough tokens but bucket E has enough tokens, the packet is colored
yellow.
{
If neither bucket C nor bucket E has enough tokens, the packet is colored red.
• If traffic policing is not configured, looks up the 802.1p priority of a packet in the 802.1p-to-drop
priority mapping table, allocates drop precedence to the packet, and colors the packet according
to the drop precedence.
{
Drop precedence 0 represents green packets.
{
Drop precedence 1 represents yellow packets.
{
Drop precedence 2 represents red packets.
NOTE:
•
The traffic policing functions that support coloring packets include common CAR and aggregation CAR.
For more information, see “
Configuring traffic policing ” and “ Configuring aggregation CAR .”
• For more information about priority mapping tables, see “ Configuring priority mapping .”
Marking packets based on their colors
Color-based priority marking supports re-marking DSCP, 802.1p priority, and local precedence.
You can configure color-based marking in the following ways:
• To mark packets based on a color set during traffic policing, configure a priority marking action for
the color in the traffic policing action car or qos car aggregative. For more information, see
“ Configuring traffic policing ” and “ Configuring aggregation CAR .”