ZyXEL Communications ZyWall ATP series User Manual page 427

Chapter 23 BWM (Bandwidth Management)
In the following example, you configure a Per user bandwidth management rule for radius-users to limit
outgoing traffic to 300 kbs. Then all radius-users (A, B and C) can send 300 kbps of traffic.
Figure 293 Bandwidth Management Per User Type
DiffServ and DSCP Marking
QoS is used to prioritize source-to-destination traffic flows. All packets in the same flow are given the
same priority. CoS (class of service) is a way of managing traffic in a network by grouping similar types of
traffic together and treating each type as a class. You can use CoS to give different priorities to different
packet types.
DiffServ (Differentiated Services) is a class of service (CoS) model that marks packets so that they
receive specific per-hop treatment at DiffServ-compliant network devices along the route based on the
application types and traffic flow. Packets are marked with DiffServ Code Points (DSCPs) indicating the
level of service desired. This allows the intermediary DiffServ-compliant network devices to handle the
packets differently depending on the code points without the need to negotiate paths or remember
state information for every flow. In addition, applications do not have to request a particular service or
give advanced notice of where the traffic is going.
Connection and Packet Directions
Bandwidth management looks at the connection direction, that is, from which interface the connection
was initiated and to which interface the connection is going.
A connection has outbound and inbound packet flows. The Zyxel Device controls the bandwidth of
traffic of each flow as it is going out through an interface or VPN tunnel.
• The outbound traffic flows from the connection initiator to the connection responder.
• The inbound traffic flows from the connection responder to the connection initiator.
For example, a LAN1 to WAN connection is initiated from LAN1 and goes to the WAN.
• Outbound traffic goes from a LAN1 device to a WAN device. Bandwidth management is applied
before sending the packets out a WAN interface on the Zyxel Device.
• Inbound traffic comes back from the WAN device to the LAN1 device. Bandwidth management is
applied before sending the traffic out a LAN1 interface.
ZyWALL ATP Series User's Guide
427