H3C Technologies H3C S7500E Series Switches - Manual (Page 18)

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IP Routing Basics Configuration
Go to these sections for information you are interested in:
z Routing
z Routing Protocol Overview
z Configuring a Router ID
z Displaying and Maintaining a Routing Table
z The term “router” in this document refers to a router in a generic sense or a Layer 3 switch.
z EA cards (such as LSQ1GP12EA and LSQ1TGX1EA) do not support IPv6 features.
Routing
Routing in the Internet is achieved through routers. Upon receiving a packet, a router finds an optimal
route based on the destination address and forwards the packet to the next router in the path until the
packet reaches the last router, which forwards the packet to the intended destination host.
Routing provides the path information that guides the forwarding of packets.
Routing Table and FIB Table
The routing table plays a key role in route selection and the forwarding information base (FIB) table
plays a key role in packet forwarding. Each router maintains a routing table and a FIB table at least.
Routes in a routing table can be divided into three categories by origin:
z Direct routes: Routes discovered by data link protocols, also known as interface routes.
z Static routes: Routes that are manually configured.
z Dynamic routes: Routes that are discovered dynamically by routing protocols.
Each entry in the FIB table specifies which physical interface a packet destined for a certain
destination should go out to reach the next hop (the next router) or the directly connected destination.
Introduction to routing table
Each router maintains a local routing table. Each routing protocol also maintains a protocol routing
table.
z Routing table of a protocol
A protocol routing table stores routes discovered by the routing protocol.
A routing protocol can redistribute and advertise routes generated by other protocols. For example,
OSPF can redistribute direct routes, static routes and IS-IS routes to the OSPF routing table and then
advertise those routes.