ZyXEL Communications USG-300 - V2.20 ED 2, Руководство пользователя

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Chapter 15 Policy and Static Routes
ZyWALL USG 300 User’s Guide
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15.4 Policy Routing Technical Reference
Here is more detailed information about some of the features you can configure in
policy routing.
NAT and SNAT
NAT (Network Address Translation - NAT, RFC 1631) is the translation of the IP
address in a packet in one network to a different IP address in another network.
Use SNAT (Source NAT) to change the source IP address in one network to a
different IP address in another network.
Assured Forwarding (AF) PHB for DiffServ
Assured Forwarding (AF) behavior is defined in RFC 2597. The AF behavior group
defines four AF classes. Inside each class, packets are given a high, medium or
low drop precedence. The drop precedence determines the probability that routers
in the network will drop packets when congestion occurs. If congestion occurs
between classes, the traffic in the higher class (smaller numbered class) is
generally given priority. Combining the classes and drop precedence produces the
Gateway IP Select the radio button and enter the IP address of the next-hop
gateway. The gateway is a router or switch on the same segment as your
ZyWALL's interface(s). The gateway helps forward packets to their
destinations.
Interface Select the radio button and a predefined interface through which the
traffic is sent.
Metric Metric represents the “cost” of transmission for routing purposes. IP
routing uses hop count as the measurement of cost, with a minimum of 1
for directly connected networks. Enter a number that approximates the
cost for this link. The number need not be precise, but it must be 0~127.
In practice, 2 or 3 is usually a good number.
OK Click OK to save your changes back to the ZyWALL.
Cancel Click Cancel to exit this screen without saving.
Table 94 Configuration > Network > Routing > Static Route > Add (continued)
LABEL DESCRIPTION