User's Manual

Table Of Contents
452
Users Manual of GPL-8000
at the next hop, the switch first checks whether the item of destination A exists in the IP cache of hardware. If
the item exists, the message will be forwarded through hardware. If the item does not exist, the message is
sent to CPU and then processed through software. IP hardware subnet routing items include the destination
subnet, mask, IP address of the next hop, interface and so on. When the IP hardware subnet routing is
enabled, after the IP cache fails to be matched, the system is to check the IP hardware subnet routing items. If
the matched item is found, the message will be directly forwarded through the next-hop IP address and the
interface designated in the matched item. If the IP hardware subnet routing item is not found, the message will
be sent to CPU for processing.
The IP hardware subnet routing has two modes: automatic and manual. In manual mode, you need to
manually configure all routing items required by the IP hardware subnet routing. Note that routing items
having longer mask of destination subnet should be configured earlier. In automatic mode, the system
automatically addes the known routes to the hardware subnet routing. All the procedure is automatic after the
hardware subnet routing is started.
46.1.2 Configuring IP Hardware Subnet Routing
Perform the following steps to configure the IP hardware subnet routing:
Step Command Description
1
[no] ip exf {default | destination
mask} {cpu| nexthop vlan vlanid}
Add or delete a hardware subnet route. Deleting a hardware
subnet route requires to specify the destination network and
mask. Replace destination and mask in the command line
with default when you delete a route. In this case, The next
hop is not CPU. The command is effective only in manual
configuration mode.
2
[no] ip exf
Enable or disable the IP hardware subnet routing.
46.1.3 Checking the State of IP Hardware Subnet Routing
Command Description
show ip exf
Displays the current state of the IP hardware subnet routing.
Configuration Example
Pay attention to the following content when you configure the routing items:
As to the direct-connecting routing, the next hop is CPU. If the next hop is a routing interface not an IP
address, do as in the direct-connecting routing.
When the number of the routing items in the system is bigger than that of the IP hardware subnet routing
items, the default routing cannot be the IP hardware subnet routing. Two or several routes, which are
prefix to each other, must be used together when IP hardware subnet routing is adopted. For other items,
advise to add heavy-traffic items to the hardware subnet routing table. Our 3224 series switches support
15 hardware subnet routes, including the default subnet route.