
Chapter 21
| VLAN Commands
Configuring VLAN Interfaces
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The following figure shows VLANs 1 and 2 configured on switches A and B, with
VLAN trunking being used to pass traffic for these VLAN groups across switches
C, D and E.
Figure 6: Configuring VLAN Trunking
Without VLAN trunking, you would have to configure VLANs 1 and 2 on all
intermediate switches – C, D and E; otherwise these switches would drop any
frames with unknown VLAN group tags. However, by enabling VLAN trunking
on the intermediate switch ports along the path connecting VLANs 1 and 2,
you only need to create these VLAN groups in switches A and B. Switches C, D
and E automatically allow frames with VLAN group tags 1 and 2 (groups that
are unknown to those switches) to pass through their VLAN trunking ports.
◆
VLAN trunking is mutually exclusive with the “access” switchport mode (see the
command). If VLAN trunking is enabled on an interface, then
that interface cannot be set to access mode, and vice versa.
◆
To prevent loops from forming in the spanning tree, all unknown VLANs will be
bound to a single instance (either STP/RSTP or an MSTP instance, depending on
the selected STA mode).
◆
If both VLAN trunking and ingress filtering are disabled on an interface, packets
with unknown VLAN tags will still be allowed to enter this interface and will be
flooded to all other ports where VLAN trunking is enabled. (In other words,
VLAN trunking will still be effectively enabled for the unknown VLAN).
Example
The following example enables VLAN trunking on ports 9 and 10 to establish a path
across the switch for unknown VLAN groups:
Console(config)#interface ethernet 1/9
Console(config-if)#vlan-trunking
Console(config-if)#interface ethernet 1/10
Console(config-if)#vlan-trunking
Console(config-if)#
Содержание ECS4120-28F
Страница 36: ...Contents 36...
Страница 38: ...Figures 38...
Страница 46: ...Section I Getting Started 46...
Страница 70: ...Chapter 1 Initial Switch Configuration Setting the System Clock 70...
Страница 86: ...Chapter 2 Using the Command Line Interface CLI Command Groups 86...
Страница 202: ...Chapter 5 SNMP Commands Additional Trap Commands 202...
Страница 210: ...Chapter 6 Remote Monitoring Commands 210...
Страница 216: ...Chapter 7 Flow Sampling Commands 216...
Страница 278: ...Chapter 8 Authentication Commands PPPoE Intermediate Agent 278...
Страница 360: ...Chapter 9 General Security Measures Port based Traffic Segmentation 360...
Страница 384: ...Chapter 10 Access Control Lists ACL Information 384...
Страница 424: ...Chapter 11 Interface Commands Power Savings 424...
Страница 446: ...Chapter 13 Power over Ethernet Commands 446...
Страница 456: ...Chapter 14 Port Mirroring Commands RSPAN Mirroring Commands 456...
Страница 488: ...Chapter 17 UniDirectional Link Detection Commands 488...
Страница 494: ...Chapter 18 Address Table Commands 494...
Страница 554: ...Chapter 20 ERPS Commands 554...
Страница 620: ...Chapter 22 Class of Service Commands Priority Commands Layer 3 and 4 620...
Страница 638: ...Chapter 23 Quality of Service Commands 638...
Страница 772: ...Chapter 25 LLDP Commands 772...
Страница 814: ...Chapter 26 CFM Commands Delay Measure Operations 814...
Страница 826: ...Chapter 27 OAM Commands 826 1 1 00 12 CF 6A 07 F6 000084 Enabled Disabled Enabled Disabled Console...
Страница 836: ...Chapter 28 Domain Name Service Commands 836...
Страница 848: ...Chapter 29 DHCP Commands DHCP Relay Option 82 848...
Страница 902: ...Section III Appendices 902...
Страница 916: ...Glossary 916...
Страница 926: ...CLI Commands 926...
Страница 937: ......
Страница 938: ...E092017 CS R02...