Static routing principle and configuration

Catalog

Routing Overview ：

How routers work ：

How routers work

The encapsulation process of router forwarding packets

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Routing Overview ：

route

• The forwarding process from the source host to the target host

（ Be able to forward packets to the right destination , And choose the best path in the forwarding process – Router ）

How routers work ：

• Forward data according to routing table

 

1. The router receives data , The destination address in the view packet is 4.1, Lookup routing table

2. Router B Packet received , View the destination address of the packet , And find the routing table

How routers work

The formation of routing table static route and default route

The encapsulation process of router forwarding packets

Configuration of static route and default route

The formation of routing table

● A collection of routing entries maintained in a router

● The router chooses the route according to the routing table

The formation of routing table

Direct connection network segment

• To configure IP Address , port UP state , Form Zhilian route

Non direct network segment （ For non directly connected network segments , Static or dynamic routing is required , Add network segment to routing table ）

Static routing

• Manually configured by the administrator , Is one-way

• inflexibility

 

What is static routing ?
Configured by the administrator , Is one-way , And lack of flexibility , Static routing requires the administrator to write one by one , And can't respond to changes in the network , So in general , The network scale for static routing is not large 、 In a network with a relatively fixed topology , If the network topology changes , The administrator will configure it manually again
Note that it is unidirectional , If you want to configure static routes to other network segments on the router , Bidirectional configuration is required
for example , In the example above , In the router A Static routing is configured on , Just tell the router A How to get there 192.168.1.0 Network segment . If router B You need to forward the packets to the router A On the Internet , Even in the router B Configure routing on

How routers work

Forward data according to routing table

Receive packets - Check the destination address - Match with the routing table to find the forwarding port - Forward to this port

Default route （ Only in export ）

When the router cannot find the routing entry of the target network in the routing table , The router forwards the request to the default routing interface （ Last section network ）

（ The destination is a huge set of addresses , The packet can be forwarded to the router A Of S0 Interface ）

Summary

• The router queries the routing table , Realize packet forwarding

• There are two ways to form a routing table: static addition and dynamic learning

• Static routing is the routing information manually added by the administrator .（ Peer network segment ）

• The default route is a special static route

The encapsulation process of router forwarding packets

Source and destination address changes （ Source and purpose IP unchanged ,MAC The address is changing ）

1.（ Source IP192.168.1.2 Purpose 192.168.2.2 Source MAC 11-11 Purpose MAC 22-22）

First ARP The broadcast parses E0 Of MAC Address . Perform the first package

2. Router A Packet received , View packets P Goal in header eP Address , Then find your own routing table . The target of the packet P The address is 4.1, Belong to 4.0 Network segment , Lu Shan Youqi a Find... In the routing table 4.0 The interface for network segment forwarding is s0 Interface . therefore , Router A Send packets from so Interface forwarding out .

3. Every router in the network forwards data in this way , Until we reach the router B, Use the same forwarding method , from EO I'll forward it ,4.1 The host receives this packet .

Comparison between switching and routing

The encapsulation process of router forwarding packets （ a key )

summary : The whole process ip The address is the same ,mac The address has been changing by learning the forwarding principle of the router , Let's sum up the difference with the switch

The principle said , Next, I will explain how to configure static routes and default routes. By configuring routes, I am also familiar with various configuration commands of Huawei routers

First configure the host ip、 Mask , gateway

Get a router and configure the interface first ip Address int g0/0/o

IP add 192.168.1.1 24

dis ip int b l/ View interface correspondence ip Address , Interface status

ip route-static Network number subnet mask next hop ip // Static routing configuration

ip route-static 0.0.0.0 0.0.0.0 Next jump ip // Default routing configuration

dis ip routing-table // View routing table （ Learn to read the routing table )

Floating route

Routing priority （ The smaller the value, the higher the priority ） If the priority is the same, compare the measures , The smaller the measure, the better , If all are the same, load sharing . Multiple links transmit data at the same time

Direct connection 0

static state 60 Default

rospf 10

IS-IS 15

rip 10o

ospf ASE 150

IBGP 255

EBGP 255

【R1】ip route-static 192.168.1.0 24 11.0.0.2 The default priority is 60, The smaller the better

【R1】 ip route-static 192.168.1.0 24 12.0.0.2 preference 70

Configure floating routes for backup , Also static routing , Alternate path

Cancel the operation undo

Finally, verify whether the host ping through