HP VPN Firewall Appliances Network Management Configuration Guide

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IP routing basics
The term "router" in this document refers to both routers and routing-capable firewalls and firewall
modules.
IP routing directs IP packet forwarding on routers based on a routing table.
A router maintains at least two routing tables: a global routing table and a FIB. The FIB table contains
only the optimal routes, and the global routing table contains all routes. The router uses the FIB table to
forward packets. For more information about the FIB table, see "Basic forwarding on the device."
Table 41 c
ategorizes routes by different criteria.
Table 41 Route categories
Criterion Cate
g
ories
Destination
• Network route—Destination is a network. The subnet mask is less than 32 bits.
• Host route—Destination is a host. The subnet mask is 32 bits.
Whether the
destination is directly
connected
• Direct route—Destination is directly connected.
• Indirect route—Destination is indirectly connected.
Origin
• Direct route—A direct route is discovered by the data link protocol on an interface,
and is also called an "interface route."
• Static route—A static route is manually configured by an administrator.
• Dynamic route—A dynamic route is dynamically discovered by a routing protocol.
To view brief information about a routing table, use the display ip routing-table command:
<Sysname> display ip routing-table
Routing Tables: Public
Destinations : 7 Routes : 7
Destination/Mask Proto Pre Cost NextHop Interface
1.1.1.0/24 Direct 0 0 1.1.1.1 GE1/1
2.2.2.0/24 Static 60 0 12.2.2.2 GE1/2
80.1.1.0/24 OSPF 10 2 80.1.1.1 GE1/3
…
A route entry includes the following key items:
• Destination—IP address of the destination host or network.
• Mask—Mask length of the IP address.
• Pre—Preference of the route. Among routes to the same destination, the one with the highest
preference is optimal.
• Cost—If multiple routes to a destination have the same preference, the one with the smallest cost
becomes the optimal route.
• NextHop—Next hop.
• Interface—Output interface.