H3C S7500E Series Ethernet Switches Operation Manual

Operation Manual – IPv4 Routing
H3C S7500E Series Ethernet Switches Chapter 1 Static Routing Configuration
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You can create the default route with both destination and mask being 0.0.0.0, and
some dynamic routing protocols, such as OSPF, RIP and IS-IS, can also generate the
default route.
1.1.3 Application Environment of Static Routing
Before configuring a static route, you need to know the following concepts:
1) Destination address and mask
In the ip route-static command, an IPv4 address is in dotted decimal format and a
mask can be either in dotted decimal format or in the form of mask length (the digits of
consecutive 1s in the mask).
2) Output interface and next hop address
While configuring a static route, you can specify either the output interface or the next
hop address depending on the specific occasion. The next hop address can not be a
local interface IP address; otherwise, the route configuration will not take effect.
In fact, all the route entries must have a next hop address. When forwarding a packet, a
router first searches the routing table for the route to the destination address of the
packet. The system can find the corresponding link layer address and forward the
packet only after the next hop address is specified.
When specifying the output interface, note that:
z If the output interface is a NULL0 or loopback interface, there is no need to
configure the next hop address.
z You are not recommended to specify a broadcast interface (such as VLAN
interface) as the output interface, because a broadcast interface may have
multiple next hops. If you have to do so, you must specify the corresponding next
hop for the output interface.
3) Other attributes
You can configure different preferences for different static routes so that route
management policies can be applied more flexibly. For example, specifying the same
preference for different routes to the same destination enables load sharing, while
specifying different preferences for these routes enables route backup.
1.2 Configuring a Static Route
1.2.1 Configuration Prerequisites
Before configuring a static route, you need to configure the IP addresses for related
interfaces.
1.2.2 Configuration Procedure
Follow these steps to configure a static route: