背景：三层交换机的e0/0要工作在三层模式与另一网络设备连接。可以选择的配置方式有两种，
1、routed Port，指在cisco switch中端口模式下运行no switchport后的端口类型，在routed port下可直接配置IP地址。
routed port典型配置如下：
int e0/0
no switchport
ip addresss 1.1.1.1 255.255.255.0
2、SVI，指使用int vlan [vlan number]得到svi接口，该接口下可直接配置IP地址。
SVI+access Port 典型配置如下：
vlan 10 //创建一个新的vlan,在该vlan下仅包含e0/0接口
exit
int e0/1
switchport mode access
switchport access vlan 10
exit
int vlan 10
ip address 1.1.1.1 255.255.255.0
exit
通过两种配置可以得到相同的效果，至少在正常使用下不会看出来太大的区别。但是不同的配置方式下仍然有些许不同。
不同之处有以下两处：
1、svi 得到mac地址和routed port不一样，在同一网段中可以观察到。其中routed port使用了物理接口的mac地址，svi使用的mac地址设备mac地址+1。
2、svi配置下e0/0仍然工作L2，routed port下的e0/0完全在L3工作。
下面引用cisco网站上关于此问题的一个回复.<https://supportforums.cisco.com/message/546252#546252>
There is a difference the way both the connection works. Although they will have the same purpose but there is the difference the way the switch ports will work.
In case of a SVI you will have eventually a Layer-2 link between the switches. This will run your normal STP and other control traffic between the switches.This will extend your STP domain from a switch to the other switch.The ports will go thorugh the normal STP states and in case of a link flap or link going down/coming back the recovery time will be a little high.
In case of a routed port between the switches,you will have a layer 3 link between the switches and will work as a normal router port. There will no STP running on the ports and the STP domain will not be extended beyond the downstream switches.Applying layer3 features like ACL's,PBR's will be a ltille easy in this case.
The Disadvantage of running routed ports is that each port will be a separate network and you will have to manage a large number of IP subnets on the network. Running a routing protocol will be a good idea in this case.
在实际组网环境中，选择SVI+access Port或routed port主要取决于连接的另一端。 通常另一端如果是PC,那么使用svi作为pc的网关会方便些。如果对端是交换机、防火墙、路由器等网络设备，建议用routed port方便运行不同路由协议。
