Ip Routing Basics; Routing Table - HP 6125XLG Configuration Manual

IP routing basics

IP routing directs IP packet forwarding on routers based on a routing table. This chapter focuses on
unicast routing protocols. For more information about multicast routing protocols, see IP Multicast
Configuration Guide.

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 Layer 3—IP Services Configuration
Guide.
Table 1 categorizes routes by different criteria.
Table 1 Route categories
Criterion
Destination
Whether the
destination is directly
connected
Origin
To view brief information about a routing table, use the display ip routing-table command:
<Sysname> display ip routing-table
Destinations : 19
Destination/Mask
0.0.0.0/32
1.1.1.0/24
1.1.1.0/32
1.1.1.1/32
1.1.1.255/32
2.2.2.0/24
80.1.1.0/24
...
A route entry includes the following key items:
Destination—IP address of the destination host or network.
•
Mask—Mask length of the IP address.
•
Categories
•
Network route—The destination is a network. The subnet mask is less than 32 bits.
•
Host route—The destination is a host. The subnet mask is 32 bits.
•
Direct route—The destination is directly connected.
•
Indirect route—The destination is indirectly connected.
•
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.
Routes : 19
Proto Pre Cost
Direct 0 0
Direct 0 0
Direct 0 0
Direct 0 0
Direct 0 0
Static 60 0
OSPF 10 2
1
NextHop Interface
127.0.0.1 InLoop0
1.1.1.1 Vlan1
1.1.1.1 Vlan1
127.0.0.1 InLoop0
1.1.1.1 Vlan1
12.2.2.2 Vlan2
80.1.1.1 Vlan3