本文档提供在运行 Cisco IOS® 软件的 Cisco Catalyst 3550/3560/3750 交换机与运行 Cisco IOS 软件的 Catalyst 6500/6000 系列交换机或 Catalyst 4500/4000 系列交换机之间配置 IEEE 802.1Q (dot1q) 中继的示例。中继是一种在两个设备之间点到点链路上传输来自若干 VLAN 的流量的方式。
您能实施以太网中继的二种方式是:
交换机间链路协议 (ISL) - Cisco 专有协议
802.1Q - IEEE 标准
尝试进行此配置之前,请确保满足以下要求:
了解 IEEE 802.1Q 中继
了解使用命令行界面 (CLI) 对 Catalyst 3560 和 Catalyst 6500/6000 系列交换机进行的配置
本文档中的信息基于以下软件和硬件版本:
运行 Cisco IOS 软件版本 12.2(25)SEA 的 Catalyst 3560 交换机
运行 Cisco IOS 软件版本 12.1(26)E1 的 Catalyst 6509 交换机
本文档中的 Catalyst 3560 配置也适用于运行 Cisco IOS 软件的 Catalyst 3550/3750 交换机。本文档中的 Catalyst 6500/6000 配置也适用于运行 Cisco IOS 软件的 Catalyst 4500/4000 系列交换机。
注意: 要了解各种 Catalyst 交换机支持的中继方法,请参阅以下文档:
本文档中的信息都是基于特定实验室环境中的设备编写的。本文档中使用的所有设备最初均采用原始(默认)配置。如果您使用的是真实网络,请确保您已经了解所有命令的潜在影响。
注意: 本文档仅包括交换机的配置文件和相关 show 命令示例的输出。有关如何在 Catalyst 交换机之间配置 802.1Q 中继的详细信息,请参阅以下文档:
配置 VLAN 的配置 VLAN 中继部分 - Catalyst 3560 系列交换机
配置用于第 2 层交换的 LAN 端口的了解 VLAN 中继部分 - 运行 Cisco IOS 软件的 Catalyst 6500 系列交换机
配置第 2 层以太网接口的了解 VLAN 中继部分 - 运行 Cisco IOS 软件的 Catalyst 4500 系列交换机
IEEE 802.1Q 使用内部标记机制。中继设备先插入 4 字节标记来识别帧所属的 VLAN,再重新计算帧校验序列 (FCS)。有关详细信息,请参阅以下文档:
使用 802.1Q 封装与 Cisco CatOS 系统软件的 Catalyst 4500/4000、5500/5000 和 6500/6000 系列交换机之间的中继的 802.1Q 中继的基本特性部分
注意: 以下是进行此配置时要记住的一些重要说明:
Catalyst 3550/3560/3750 系列交换机上的所有以太网接口均可支持 802.1Q 和 ISL 封装。默认情况下,Catalyst 3550 交换机上的以太网接口是第 2 层 (L2) 端口。
Catalyst 6500/6000 系列交换机上的所有以太网端口均可支持 802.1Q 和 ISL 封装。
默认情况下,运行 Cisco IOS 软件的 Catalyst 4500 系列交换机支持 ISL 和 802.1Q 中继模式。这在 WS-X4418-GB 和 WS-X4412-2GB-T 模块上阻塞千兆端口以外的所有接口上均受到支持。这些端口不支持 ISL 而只支持 802.1Q 中继。端口 3 至 18 是 WS-X4418-GB 模块上的阻塞千兆端口。端口 1 至 12 是 WS-X4412-2GB-T 模块上的阻塞千兆端口。
注意: 如果端口到背板的连接超载,则该端口是阻塞端口。
Catalyst 6500/6000 与 Catalyst 4500 平台之间的主要区别在于默认接口配置。默认情况下,运行 Cisco IOS 软件的 Catalyst 6500/6000 交换机中处于关闭模式的接口为第 3 层 (L3) 路由端口。运行 Cisco IOS 软件的 Catalyst 4500/4000 交换机已启用所有接口。默认情况下,接口是 L2 交换机端口。
当 802.1Q 封装用于 Catalyst 3750 交换机上的中继接口时,可在 show interface 输出中看到残帧,因为 61-64 字节的有效 802.1Q 封装数据包(包括 q 标记)被 Catalyst 3750 交换机算作是过小帧,即使这些数据包被正确地转发。有关详细信息,请参阅 Cisco bug ID CSCec14238(仅限注册用户)。
本部分提供有关如何配置本文档所述功能的信息。
注意: 使用命令查找工具(仅限注册用户)可获取有关本部分所使用命令的详细信息。
本文档使用以下网络设置:
注意: Catalyst 3560 上的千兆以太网接口是 10/100/1000 Mbps 协商以太网接口。因此,在此网络图中,Catalyst 3560 上的千兆端口连接到 Catalyst 6500 上的快速以太网 (100 Mbps) 端口。
本文档使用以下配置:
Catalyst 3560 交换机 |
---|
!--- Note: This example creates VLAN 1 and VLAN 2 !--- and sets the VLAN Trunk Protocol (VTP) mode to transparent. Use your !--- network as a basis and set the VTP mode accordingly. For more details, !--- refer to Configuring VLANs. version 12.2 no service pad service timestamps debug uptime service timestamps log uptime no service password-encryption ! hostname 3560 ! !--- This is the privileged mode password for the example. enable password mysecret ! ip subnet-zero ! vtp mode transparent ! !--- VLAN 2 is created. This is visible only when you set VTP mode !--- to transparent. vlan 2 ! ! !--- The Gigabit Ethernet interface on the Catalyst 3560 is a 10/100/1000 Mbps !--- negotiated Ethernet interface. Therefore, the Gigabit port on the !--- Catalyst 3560 is connected to a Fast Ethernet port on the Catalyst 6500. !--- Configure the trunk on the Gigabit Ethernet 0/1 interface. interface GigabitEthernet0/1 !--- Configure trunk encapsulation as dot1q. !--- For details on trunking, refer to Configuring VLANs. switchport trunk encapsulation dot1q !--- Enable trunking on the interface. switchport mode trunk no ip address snmp trap link-status ! ! !--- Interfaces Gigabit Ethernet 0/2 through 0/5 are placed in VLAN 1. !--- In order to configure the interface as an L2 port, !--- refer to the Configuring Ethernet Interfaces section !--- of Configuring Interface Characteristics. All L2 ports are placed !--- in VLAN 1, by default. interface GigabitEthernet0/2 switchport mode access no ip address snmp trap link-status ! interface GigabitEthernet0/3 switchport mode access no ip address snmp trap link-status ! ! interface GigabitEthernet0/4 switchport mode access no ip address snmp trap link-status ! interface GigabitEthernet0/5 switchport mode access no ip address snmp trap link-status ! ! !--- Interfaces Gigabit Ethernet 0/6 through 0/12 are placed in VLAN 2. interface GigabitEthernet0/6 switchport access vlan 2 switchport mode access no ip address snmp trap link-status ! !--- Output suppressed. ! interface GigabitEthernet0/12 switchport access vlan 2 switchport mode access no ip address snmp trap link-status ! interface Vlan1 !--- This is the IP address for management. ip address 10.1.1.1 255.255.255.0 ! ip classless ip http server ! ! line con 0 transport input none line vty 0 4 !--- This is the privileged mode password for the example. password mysecret login line vty 5 15 login ! end |
Catalyst 6500 交换机 |
---|
!--- Note: This example creates VLAN 1 and VLAN 2 and sets !--- the VTP mode to transparent. Use your network as a basis and set the VTP !--- mode accordingly. For more details, refer to Configuring VLANs. Current configuration : 4812 bytes version 12.1 service timestamps debug uptime service timestamps log uptime no service password-encryption ! hostname Cat6500 ! vtp mode transparent ip subnet-zero ! ! mls flow ip destination mls flow ipx destination ! !--- This is the privileged mode password for the example. enable password mysecret ! redundancy mode rpr-plus main-cpu auto-sync running-config auto-sync standard ! ! !--- This enables VLAN 2. vlan 2 ! ! interface GigabitEthernet1/1 no ip address shutdown ! interface GigabitEthernet1/2 no ip address shutdown ! !--- The Gigabit Ethernet interface on the Catalyst 3560 is a 10/100/1000 Mbps !--- negotiated Ethernet interface. Therefore, the Gigabit port on the Catalyst 3560 !--- is connected to a Fast Ethernet port on the Catalyst 6500. interface FastEthernet3/1 no ip address !--- You must issue the switchport command once, !--- without any keywords, in order to configure the interface as an L2 port for the !--- Catalyst 6500 series switch that runs Cisco IOS Software. !--- On a Catalyst 4500 series switch that runs Cisco IOS Software, all ports are L2 !--- ports by default. Therefore, if you do not change the default configuration, !--- you do not need to issue the switchport command. !--- For more details, refer to Configuring Layer 2 Ethernet Interfaces !--- for the Catalyst 4500 series switch that runs Cisco IOS Software. switchport !--- Configure trunk encapsulation as dot1q. !--- For more details on trunking, refer to !--- Configuring LAN Ports for Layer 2 Switching for the Catalyst 6500 series switch !--- that runs Cisco IOS Software, or Configuring Layer 2 Ethernet Interfaces !--- for the Catalyst 4500/4000 series switch that runs Cisco IOS Software. switchport trunk encapsulation dot1q !--- Enable trunking on the interface. switchport mode trunk ! !--- Configure interfaces Fast Ethernet 3/2 through 3/24 to be in access mode. !--- By default, all access ports are configured in VLAN 1. !--- For more details, refer to Configuring LAN Ports for Layer 2 Switching !--- for the Catalyst 6500 series switch that runs Cisco IOS Software, or !--- Configuring Layer 2 Ethernet Interfaces for the Catalyst 4500/4000 series !--- switch that runs Cisco IOS Software. interface FastEthernet3/2 no ip address switchport switchport mode access ! !--- Output suppressed. ! interface FastEthernet3/24 no ip address switchport switchport mode access ! !--- Fast Ethernet 3/25 through 3/48 are placed in VLAN 2. !--- For more details, refer to Configuring LAN Ports for Layer 2 Switching !--- for the Catalyst 6500 series switch that runs Cisco IOS Software, !--- or Configuring Layer 2 Ethernet Interfaces for the Catalyst 4500/4000 !--- series switch that runs Cisco IOS Software. interface FastEthernet3/25 no ip address switchport switchport access vlan 2 switchport mode access ! !--- Output suppressed. ! interface FastEthernet3/48 no ip address switchport switchport access vlan 2 switchport mode access ! ! interface Vlan1 !--- This is the IP address for management. ip address 10.1.1.2 255.255.255.0 ! ! ip classless no ip http server ! ! ip classless ip http server ! line con 0 exec-timeout 0 0 transport input none line vty 0 4 !--- This is the Telnet password for the example. password mysecret login ! end |
注意: 如果向不存在的 VLAN 分配接口,则接口将一直关闭,直至在 VLAN 数据库中创建 VLAN。有关详细信息,请参阅配置 VLAN 的创建或修改以太网 VLAN 部分。
使用本部分可确认配置能否正常运行。
命令输出解释程序(仅限注册用户)(OIT) 支持某些 show 命令。 使用 OIT 可查看对 show 命令输出的分析。
在 Catalyst 3550/3560/3750/6500/4500 交换机上,请使用以下命令:
show interfaces interface_type module/port trunk
show interfaces interface_type模块/端口switchport
show vlan
show vtp status
show interfaces interface_type module/port trunk - 此命令显示接口的中继配置以及能够通过中继为其传输流量的 VLAN 编号。
3560# show interface gigabitethernet 0/1 trunk Port Mode Encapsulation Status Native vlan Gi0/1 on 802.1q trunking 1 Port Vlans allowed on trunk Gi0/1 1 4094 Port Vlans allowed and active in management domain Gi0/1 1-2 Port Vlans in spanning tree forwarding state and not pruned Gi0/1 1-2
show interfaces interface_type module/port switchport - 此命令显示接口的交换机端口配置。
在显示器中,选中 Operational Mode 和 Operational Trunking Encapsulation 字段。
3560# show interface gigabitethernet 0/1 switchport Name: Gi0/1 Switchport: Enabled Administrative Mode: trunk Operational Mode: trunk Administrative Trunking Encapsulation: dot1q Operational Trunking Encapsulation: dot1q Negotiation of Trunking: On Access Mode VLAN: 1 (default) Trunking Native Mode VLAN: 1 (default) Voice VLAN: none Administrative private-vlan host-association: none Administrative private-vlan mapping: none Administrative private-vlan trunk native VLAN: none Administrative private-vlan trunk encapsulation: dot1q Administrative private-vlan trunk normal VLANs: none Administrative private-vlan trunk private VLANs: none Operational private-vlan: none Trunking VLANs Enabled: ALL Pruning VLANs Enabled: 2-1001 Capture Mode Disabled Capture VLANs Allowed: ALL Protected: false Unknown unicast blocked: disabled Unknown multicast blocked: disabled Appliance trust : none
show vlan - 此命令提供有关 VLAN 及属于特定 VLAN 的端口的信息。
3560# show vlan VLAN Name Status Ports ---- -------------------------------- --------- ------------------------------- 1 default active Gi0/2, Gi0/3, Gi0/4, Gi0/5 2 VLAN0002 active Gi0/6, Gi0/7, Gi0/8, Gi0/9 Gi0/10, Gi0/11, Gi0/12 1002 fddi-default act/unsup 1003 token-ring-default act/unsup 1004 fddinet-default act/unsup 1005 trnet-default act/unsup !--- Output suppressed.
注意: 输出中显示的端口只是接入端口。但是,配置为中继以及处于“未连接”状态的端口也显示在 show vlan 输出中。
show vtp status - 此命令显示有关 VTP 管理域、状态和计数器的一般信息。
3560# show vtp status VTP Version : 2 Configuration Revision : 0 Maximum VLANs supported locally : 1005 Number of existing VLANs : 6 VTP Operating Mode : Transparent VTP Domain Name : VTP Pruning Mode : Disabled VTP V2 Mode : Disabled VTP Traps Generation : Disabled MD5 digest : 0x4A 0x55 0x17 0x84 0xDB 0x99 0x3F 0xD1 Configuration last modified by 10.1.1.1 at 0-0-00 00:00:00 3560# ping 10.1.1.2 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 10.1.1.2, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/4 ms 3560#
show interfaces interface_type module/port trunk - 此命令显示接口的中继配置以及能够通过中继为其传输流量的 VLAN 编号。
Cat6500# show interfaces fastethernet 3/1 trunk Port Mode Encapsulation Status Native vlan Fa3/1 on 802.1q trunking 1 Port Vlans allowed on trunk Fa3/1 1 4094 Port Vlans allowed and active in management domain Fa3/1 1-2 Port Vlans in spanning tree forwarding state and not pruned Fa3/1 1-2
show interfaces interface_type module/port switchport - 此命令显示接口的交换机端口配置。
在显示器中,选中 Operational Mode 和 Operational Trunking Encapsulation 字段。
cat6500# show interface fastethernet 3/1 switchport Name: Fa3/1 Switchport: Enabled Administrative Mode: trunk Operational Mode: trunk Administrative Trunking Encapsulation: dot1q Operational Trunking Encapsulation: dot1q Negotiation of Trunking: On Access Mode VLAN: 1 (default) Trunking Native Mode VLAN: 1 (default) Voice VLAN: none Administrative private-vlan host-association: none Administrative private-vlan mapping: none Administrative private-vlan trunk native VLAN: none Administrative private-vlan trunk encapsulation: dot1q Administrative private-vlan trunk normal VLANs: none Administrative private-vlan trunk private VLANs: none Operational private-vlan: none Trunking VLANs Enabled: ALL Pruning VLANs Enabled: 2-1001 Capture Mode Disabled Capture VLANs Allowed: ALL
show vlan - 此命令提供有关 VLAN 及属于特定 VLAN 的端口的信息。
Cat6500# show vlan VLAN Name Status Ports ---- -------------------------------- --------- ------------------------------- 1 default active Fa3/2, Fa3/3, Fa3/4, Fa3/5 Fa3/6, Fa3/7, Fa3/8, Fa3/9 Fa3/10, Fa3/11, Fa3/12, Fa3/13 Fa3/14, Fa3/15, Fa3/16, Fa3/17 Fa3/18, Fa3/19, Fa3/20, Fa3/21 Fa3/22, Fa3/23, Fa3/24 2 VLAN0002 active Fa3/25, Fa3/26, Fa3/27, Fa3/28 Fa3/29, Fa3/30, Fa3/31, Fa3/32 Fa3/33, Fa3/34, Fa3/35, Fa3/36 Fa3/37, Fa3/38, Fa3/39, Fa3/40 Fa3/41, Fa3/42, Fa3/43, Fa3/44 Fa3/45, Fa3/46, Fa3/47, Fa3/48 1002 fddi-default act/unsup 1003 token-ring-default act/unsup 1004 fddinet-default act/unsup 1005 trnet-default act/unsup !--- Output suppressed.
注意: 显示的端口仅是您已配置为第 2 层非中继(接入)端口的那些端口。配置为中继以及处于“未连接”状态的端口也显示在 show vlan 输出中。有关详细信息,请参阅配置用于第 2 层交换的 LAN 端口的配置用于第 2 层交换的 LAN 接口部分。
show vtp status - 此命令显示有关 VTP 管理域、状态和计数器的一般信息。
Cat6500# show vtp status VTP Version : 2 Configuration Revision : 0 Maximum VLANs supported locally : 1005 Number of existing VLANs : 6 VTP Operating Mode : Transparent VTP Domain Name : VTP Pruning Mode : Disabled VTP V2 Mode : Disabled VTP Traps Generation : Disabled MD5 digest : 0xBF 0x86 0x94 0x45 0xFC 0xDF 0xB5 0x70 Configuration last modified by 10.1.1.2 at 0-0-00 00:00:00
ping
Cat6500# ping 10.1.1.1 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 10.1.1.1, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/4 ms
目前没有针对此配置的故障排除信息。有关与中继和 802.1Q 配置相关的常见问题,请参阅文档使用 802.1Q 封装和 Cisco CatOS 系统软件的 Catalyst 4500/4000、5500/5000 和 6500/6000 系列交换机之间的中继的常见错误部分。