ZyXEL Communications NXC5200 User Manual page 198

Chapter 12 Policy and Static Routes
• Cost Savings – IPPR allows organizations to distribute interactive traffic on high-
bandwidth, high-cost paths while using low-cost paths for batch traffic.
• Load Sharing – Network administrators can use IPPR to distribute traffic among
multiple paths.
Static Routes
The NXC usually uses the default gateway to route outbound traffic from
computers on the LAN to the Internet. To have the NXC send data to devices not
reachable through the default gateway, use static routes.
Policy Routes Versus Static Routes
• Policy routes are more flexible than static routes. You can select more criteria
for the traffic to match and can also use schedules, NAT, and bandwidth
management.
• Policy routes are only used within the NXC itself. Static routes can be
propagated to other routers.
• Policy routes take priority over static routes. If you need to use a routing policy
on the NXC and propagate it to other routers, you could configure a policy route
and an equivalent static route.
DiffServ
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.
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NXC5200 User's Guide