Shulou(Shulou.com)06/02 Report--

Network construction of small and medium-sized enterprises

I. default route

1. What is the default route?

A default route is a special static route that is also a default gateway for stub hosts.

-- the destination network of the default route is 0.0.0.0amp 0.0.0.0, which can match any destination address.

-- default routes are used only if no explicit matching route entries are found in the routing table

2. Configure the default route

When accessing Internet, there is only one network egress, so it is not necessary to configure all static routes.

System-view

[Huawei] ip route-static 0.0.0.0 0.0.0.0 surprise address

2. Floating routing

1. What is a floating route?

(1) limitations of a single route

There is only the "best" path.

There is a single point of risk. Once the communication is interrupted, the communication will be interrupted directly.

(2) definition and advantages of floating routing

-- configure a static route with a larger administrative distance as an emergency-triggered backup path.

If the primary route is valid, the floating route does not appear in the routing table.

(3) configure floating routing

System-view

[Huawei] ip route-static 192.168.4.0 255.255.255.0 192.168.2.2 preference 80

[Huawei] ip route-static 192.168.4.0 255.255.255.0 192.168.3.2 preference 90

Overview of layer 3 switching

1. What is layer 3 switching?

-- using layer 3 switching technology to realize inter-VLAN communication.

-- layer 3 switching = layer 2 switching + layer 3 forwarding.

2. Overview of virtual interface

-the VLAN interface configured on the layer 3 switch is a virtual interface

-- using Vlanif (VLAN interface) to implement inter-VLAN routing

The introduction of VLAN interface makes the application more flexible.

System-view

[Huawei] interface Vlanif + VLAN interface number

3. Configuration of layer 3 switch

-- determine which VLAN needs to be configured with gateways

-- create the VLAN if it is not available on the layer 3 switch

-- create an associated SVI for each VLAN

-- configure each SVI with an IP address

-- configure dynamic or static routing for layer 3 switches, if necessary.

4. Layer 3 switch to realize VLAN interworking

-- configure VLAN and Trunk on layer 2 switch

-- configure VLAN and Trunk on layer 3 switch

-View the routing table on the layer 3 switch.

5. Configure routing on layer 3 switch

-- configure VLAN and Trunk

-- configure routing on layer 3 switches and routers

-View routes on layer 3 switches.

Interworking-switching within the same VLAN.

There is no communication between different VLAN, if you want to achieve interworking, you must use-routing / pathfinding.

Requirements:

Realize the interworking between different VLAN

Preparatory techniques:

The concept of exchange

-Communication between the same network segment

-implementation device: switch

-essential skills: how it works

The concept of routin

-Communication between unreachable network segments

-implementation device: router

-essential skills: how it works | configuration command

The router only cares about the "destination IP address" in the packet; # determines whether the "destination IP address" matches the "local routing table": & if the match is successful, it is forwarded directly according to the specified port of the route entry & if the match fails Then directly discard DIP:192.168.2.1 vs. Display ip routing-table 192.168.12.0 next-hop-ip DIP 24 next-hop-ip DIP: 192.168.1.1 vs. Display ip routing-table 192.168.1.0 Uni24 100.1.1.1 0.0.0.0amp 0 192.168.23.2 192.168.0.0Universe 16 192.168.12.1 Features of the default route: # an entry Can represent all networks. # in the routing table, for the "least accurate" route, the last route entry looked up by the router [the principle for the router to find the routing table: the longer the match, the more accurate] # when there is only one network exit in the network, it is recommended to use "default route". Ip route-static 0.0.0.0 0.0.0.0 x.x.x.x configuration ideas:

1. IP address planning

192.168.12.0/24: R1--R2

192.168.23.0/24: R2--R3

192.168.1.0/24: R1--PC1

192.168.2.0/24: R3--PC2

2. IP address configuration

PC-1: 192.168.1.254

PC-2: 192.168.2.254

3. Static route configuration

R1:

Ip route-static 192.168.2.0 255.255.255.0 192.168.12.2

R2:

Ip route-static 192.168.2.0 255.255.255.0 192.168.23.3

Ip route-static 192.168.1.0 255.255.255.0 192.168.12.1

R3:

Ip route-static 0.0.0.0 0.0.0.0 192.168.23.2

4. Verification and testing

Display ip interface brief

Display ip routing-table

Ping x.x.x.x

Routing attributes:

Preference-priority, also known as "administrative distance".

Value range: 1-255 [theoretical value range: 0murmur255]

Meaning:

Indicates the stability of the route. The smaller the value, the more stable the route.

Cost-cost.

Meaning:

Indicates the distance to a route; the smaller the value, the closer it is to the destination network.

The principle for a router to select a "route entry" to enter the routing table:-- > can form a routing table

1. First compare the priority, the smaller the value, the better; if the same, then (2)

2. secondly, compare the cost value, the smaller the better.

Note:

The above principles are used only when comparing multiple paths to the same destination network.

That is, if the destination networks of multiple route entries are different, it is not necessary to compare "preference" and "cost"

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Floating route:

-function: to back up the main link

-configuration:

Ip route-static 0.0.0.0 0.0.0.0 192.168.100.2 preference 80

-verify: display current-configuration-the above configuration command exists in the configuration file at this time, but there is no quota for this route entry in the routing table.-Test: 1. Before disconnecting the main link, check the routing table: 2. After disconnecting the primary link, check the routing table again: at this time, there is a route using the backup path. 3. Reconnect the main link and check the routing table again: what appears is the route corresponding to the main link.

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Requirements:

Realize the communication between hosts of different VLAN

Analysis:

The IP addresses configured by hosts with different VLAN belong to different IP network segments.

Therefore, the communication between different VLAN hosts should be a "routing" problem.

If you want to achieve "routing interworking between different network segments", you must use the device-gateway. The so-called gateway equipment refers to the devices that can connect different network segments, such as routers, multi-layer switches, firewalls and so on. PS: in essence, a gateway is a "port" concept, which is reflected in the device configuration and should be an IP address.

Configuration:

1. IP address planning

2. Complete the configuration of "switched network":

Create VLAN, assign ports, create trunk 3, configure host IP address

@ configure host IP address br/ > 3, configure host IP address

@ configure the host IP address

4. Determine and configure the gateway IP address

# Huawei layer 3 switch cannot configure IP address directly on the port

# therefore, when Huawei layer 3 switch calls gateway devices, the gateway IP address is configured on the "virtual interface".

# on Huawei's layer 3 switch, routing is enabled by default

Deployment of gateway IP addresses on the same switch:

Configuration commands:

SW1-

Interface vlanif 13-- > configure the gateway IP address for VLAN 13

Ip address 192.168.13.254 255.255.255.0

Quit

Interface vlanif 24-- > configure the gateway IP address for VLAN 24

Ip address 192.168.24.254 255.255.255.0

Quit

Verify the command:

Display ip interface brief-- > View the locally configured gateway IP address port

Display ip routing-table-- > View the local routing table, including network segment routes for VLAN 13 and 24

Note: whether it is Cisco or Huawei. Each VLAN on a layer 3 switch corresponds to a virtual interface, and the configured IP address of the virtual interface is the "gateway" IP address of all the member hosts of the VLAN.

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Deployment of gateway IP addresses on different switches:

Requirements:

SW1 acts as the gateway for VLAN 13

SW2 acts as the gateway for VLAN 24

Realize the interworking between PC-1 and PC-4

Configuration ideas:

0. Plan the IP address and configure the end host IP and gateway IP

1. Create a VLAN

2. Configure port mode

3. Put the Access port into the correct VLAN

4. Trunk port allows all VLAN

5. Configure VLANIF (interface vlanif) for VLAN 13 on SW1, IP:192.168.13.254 255.255.255.0

6. Configure VLANIF (interface vlanif) for VLAN 24 on SW2, IP:192.168.24.254 255.255.255.0

7. Configure a new VLAN between SW1 and SW2 and configure VLANIF to build a new layer 3 interconnection link between SW1-SW2.

For example: vlan 100

Create VLAN 100on SW1; configure vlanif 100-> ip address 192.168.100.1 255.255.255.0

Create VLAN 100on SW2; configure vlanif 100-> ip address 192.168.100.2 255.255.255.0

8. Configure a "static route" to VLAN 24 on SW1:

Ip route-static 192.168.24.0 255.255.255.0 192.168.100.2

9. Configure a "static route" to VLAN 13 on SW2:

Ip route-static 192.168.13.0 255.255.255.0 192.168.100.1

10. Verification and testing

SW1/2:

Display ip routing-table

PC-1:

Ping 192.168.24.4

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