交换机上配置trunk端口时建议先将端口shutdown,配置完毕后再no shutdown。
# L9 j* N% B u8 j- @+ ]7 E/ eISL:思科私有,VLAN范围小,对QoS支持不好,没有native VLAN的概念,新版的CISCO IOS已经不支持ISL,而使用IEEE802.1q。
8 r( N( E7 U: `9 x& e4 I802.1Q在以太网帧中插入4字节的TAG字段并重新计算CRC值,而ISL不改变以太网帧结构,而采用封装方式,在以太网帧前封装26字节的ISL头部,后面加上4字节的CRC校验。
9 h, {: s( U; T9 i1 q# DTRUNK链路双方端口的Native vlan一定要一致,否则以太网帧经过TRUNK链路时VLAN会“跳变”。- \/ m& p' D- h, a
PVLAN端口类型:! J1 g7 T) J4 Q6 T0 p0 ]5 m
• Isolated: Communicate with only promiscuous ports
5 r! _" C3 Q( o• Promiscuous: Communicate with all other ports
9 R, d( K N" B• Community: Communicate with other members of community and all promiscuous ports
' ~: u. k; @) y/ a# Q& ]) s/ cA PVLAN uses VLANs in three ways: 4 y! x$ e! E% U; r+ f9 G
• As a primary VLAN: Carries traffic from promiscuous ports to isolated, community, and other promiscuous ports in the same primary VLAN. : U7 f2 U* B2 Q9 C" L0 C
• As an isolated VLAN: Carries traffic from isolated ports to a promiscuous port. ; N: r1 Y s, e$ }1 u
• As a community VLAN: Carries traffic between community ports and to promiscuous ports. You can configure multiple community VLANs in a PVLAN.
# ^% b! h% q2 B0 {Isolated and community VLANs are called secondary VLANs. |