"Marking" a packet allows that packet to be treated differently as it goes through your network depending on the marking. For example, you can mark a VoIP (Voice over IP) packet such that it gets priority over normal data traffic to provide it with a better Quality of Service (QoS).
A marking could be one of the following:
- CoS (Class of Service)
- DSCP (DiffServ Code Point)
- IP Precedence
The way you mark a packet depends on your network device (each vendor does it differently). But basically you first match a criteria (say VoIP traffic, or DNS, etc) and then you set the bits on the packet (again vendor specific) and then you pass it along with the set bits. Once you mark the packet then as the packet goes through the network each network element that receives the packet would have to look for the marking (i.e. the properly set bits) and act accordingly.
Hope that helps as a starting point.
Casey
|