H3C S7500E Series Ethernet Switches Operation Manual

Operation Manual – IP Routing Overview

H3C S7500E Series Ethernet Switches Chapter 1 IP Routing Overvie

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Chapter 1 IP Routing Overview

Go to these sections for information you are interested in:

z IP Routing and Routing Table

z Routing Protocol Overview

z Displaying and Maintaining a Routing Table

 Note:

z The term “router” in this document refers to a Layer 3 switch running routing

protocols.

z Currently, the LSQ1GP12EA board on S7500E series Ethernet switches does not

support IPv6 features.

1.1 IP Routing and Routing Table

1.1.1 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.

1.1.2 Routing Through a Routing Table

I. Routing table

Routing tables play a key role in routing. Each router maintains a routing table, and

each entry in the 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.

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.

II. Contents of a routing table

A routing table includes the following key items: