BROCADE IP PRIMER

PowerPower49F Link 50F49F Link 50FConsole1 3 5 7 9 1113 15 17 19 21 2325 27 29 31 33 3537 39 41 43 45 471F 2F 3F 4F2 4 6 8 10 1214 16 18 20 22 2426 28 30 32 34 3638 40 42 44 46 48Console1 3 5 7 9 1113 15 17 19 21 2325 27 29 31 33 3537 39 41 43 45 471F 2F 3F 4F2 4 6 8 10 1214 16 18 20 22 2426 28 30 32 34 3638 40 42 44 46 48Configuring VLANsVLAN 20VLAN 10e125th Floor SwitchCFOVLAN 20VLAN 104th Floor SwitchMarketingAccountingWhen traffic originates from the CFO's workstation, it travels to the fifth floorswitch. The fifth floor switch knows it needs to pass the frames to the two-porttrunk. It also knows that the two-port trunk is tagged, so it adds the 4-byte802.1q header to the frame. Inside that header, it specifies that it received thetraffic from a host who is a member of VLAN 10. It then sends the alteredframes through the two-port trunk.When the fourth floor switch receives the frames, it recognizes that they aretagged (good news, because the fourth floor switch's ports 1 and 2 are taggedas well). The switch looks at the VLAN ID portion of the 802.1q header, andrealizes that the frames are meant for VLAN 10. It also knows that it will bepassing the frames to an untagged port (the final destination; one of the workstationsin the Accounting department). Because of this, it removes the802.1q header from the frames, and passes the frames to their destination.This same process is used (in reverse) when the Accounting department sendsframes back to the CFO. This is the same process that is used when the Marketingdepartment on the fourth floor wants to send frames to the Marketingdepartment workstations on the fifth floor. This is how the switches know theboundaries of the defined VLAN.Brocade IP Primer 179