目录

一、理论

1.Linux Bridge 

二、实验

1.LBR 网桥管理

三、问题

1.Linux虚拟交换机如何增删

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一、理论

1.Linux Bridge 

Linux Bridge（网桥）是用纯软件实现的虚拟交换机，有着和物理交换机相同的功能，例如二层交换，MAC地址学习等。因此我们可以把tun/tap，veth pair等设备绑定到网桥上，就像是把设备连接到物理交换机上一样。此外它和veth pair、tun/tap一样，也是一种虚拟网络设备，具有虚拟设备的所有特性，例如配置IP，MAC地址等。

Linux Bridge通常是搭配KVM、docker等虚拟化技术一起使用的，用于构建虚拟网络。

二、实验

1.LBR 网桥管理

(1) SUSE系统用WinSCP拷贝轻量镜像TinyCore-11.0.iso

(2)准备安装

(3)任意选一个

(4)弹出配置界面

(5)修改虚拟机名称

(6)查看硬件

(7)查看宿主机设备

(8)外部设备Cirrus为图形化设备

(9)磁盘存放目录

(10)进入编辑界面

(11)协议支持多种格式

(12)修改协议

(13)网络适配器

(14)编辑页面，查看类型为半虚拟化设备

(15)也有全虚拟化设备可以选择

(16)这里选择全虚拟化并指定网桥br0

(17)选择apply.

(18)选择挂载光驱

(19)选择apply

(20)点击ok

(21)选择第3个

(22)进入TinyCore系统查看所有网卡

(23)TinyCore系统指定网卡

(24)SUSE系统网桥已新增虚拟端口vnet0

SUSE:~ # brctl show
bridge name	bridge id		STP enabled	interfaces
br0		8000.000c29a7aa24	no		eth0vnet0
br1		8000.000000000000	no

(25)SUSE系统查看虚拟网卡

SUSE:~ # ip add show
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue state UNKNOWN link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00inet 127.0.0.1/8 brd 127.255.255.255 scope host loinet 127.0.0.2/8 brd 127.255.255.255 scope host secondary loinet6 ::1/128 scope host valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master br0 state UP qlen 1000link/ether 00:0c:29:a7:aa:24 brd ff:ff:ff:ff:ff:ffinet6 fe80::20c:29ff:fea7:aa24/64 scope link valid_lft forever preferred_lft forever
7: br0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP link/ether 00:0c:29:a7:aa:24 brd ff:ff:ff:ff:ff:ffinet 192.168.204.133/24 brd 192.168.204.255 scope global br0inet6 fe80::20c:29ff:fea7:aa24/64 scope link valid_lft forever preferred_lft forever
10: br1: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN link/ether c6:f2:b3:25:18:90 brd ff:ff:ff:ff:ff:ff
11: vnet0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master br0 state UNKNOWN qlen 500link/ether fe:54:00:01:3c:53 brd ff:ff:ff:ff:ff:ffinet6 fe80::fc54:ff:fe01:3c53/64 scope link valid_lft forever preferred_lft forever

(26)brctl帮助命令

SUSE:~ # brctl --help
Usage: brctl [commands]
commands:addbr     	<bridge>		add bridgedelbr     	<bridge>		delete bridgeaddif     	<bridge> <device>	add interface to bridgedelif     	<bridge> <device>	delete interface from bridgesetageing 	<bridge> <time>		set ageing timesetbridgeprio	<bridge> <prio>		set bridge prioritysetfd     	<bridge> <time>		set bridge forward delaysethello  	<bridge> <time>		set hello timesetmaxage 	<bridge> <time>		set max message agesetpathcost	<bridge> <port> <cost>	set path costsetportprio	<bridge> <port> <prio>	set port priorityshow      	[ <bridge> ]		show a list of bridgesshowmacs  	<bridge>		show a list of mac addrsshowstp   	<bridge>		show bridge stp infostp       	<bridge> {on|off}	turn stp on/off

(27)2口取到MAC地址

SUSE:~ # brctl showmacs br0
port no	mac addr		is local?	ageing timer1	00:0c:29:74:e7:ff	no		   8.081	00:0c:29:a7:aa:24	yes		   0.001	00:50:56:c0:00:08	no		   0.001	00:50:56:e4:32:85	no		 284.002	fe:54:00:01:3c:53	yes		   0.00

(28)查看TinyCore网卡，TinyCore的eth0虚拟网卡已与宿主机SUSE的vnet0虚拟端口实现绑定

三、问题

1.Linux虚拟交换机如何增删

（1）查看Linux Bridge信息

SUSE:~ # brctl show
bridge name	bridge id		STP enabled	interfaces
br0		8000.000c29a7aa24	no		eth0

（2）添加虚拟交换机

SUSE:~ # brctl addbr br1

SUSE:~ # brctl show
bridge name	bridge id		STP enabled	interfaces
br0		8000.000c29a7aa24	no		eth0
br1		8000.000000000000	no

（3）删除虚拟交换机

SUSE:~ # brctl delbr br1

SUSE:~ # brctl show
bridge name	bridge id		STP enabled	interfaces
br0		8000.000c29a7aa24	no		eth0