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 48Chapter 8: Virtual Local Area Network (VLAN)Now, any traffic that needs to flow from 172.18.1.0/24 to 172.22.2.0/24 (andvice versa) can travel through the router. The router has one interface(172.18.1.1) in the Accounting VLAN, and one interface (172.22.2.1) in theMarketing VLAN. Problem solved, right? Well, that is, until the CFO finds outyou want to spend several thousand dollars to solve the problem. Now, itdoesn't look so hot. Wouldn't it be great if you could somehow squeeze thepower of the router into your already existing switches? You can see where I'mgoing with this, can't you?What makes a VLAN a Layer 3 VLAN? Two things, really. First, you must be runningrouting code (Base Layer 3 or Full Router). Second, you need to configurea router-interface. Think of the router-interface as the physical interface on therouter we used in the previous example. This time, we'll configure it inside thefourth floor switch (after we install routing code on it, of course).VLAN 20VLAN 10e1-2e125th Floor SwitchCFOe1-2VLAN 20 VLAN 10ve 172.22.2.1/24 ve 172.18.1.1/244th Floor SwitchMarketing172.22.2.0/24Accounting172.18.1.0/24To configure the router-interfaces, we first need to declare the routerinterfaces:BR-4thFloorSwitch#conf tBR-4thFloorSwitch(config)#vlan 10BR-4thFloorSwitch(config-vlan-10)#router-interface ve 10BR-4thFloorSwitch(config-vlan-10)#vlan 20BR-4thFloorSwitch(config-vlan-20)#router-interface ve 20When you declare a router-interface, you use a special interface type -- ve. Itstands for virtual Ethernet. The interface you're creating doesn't physicallyexist. Think of it as an interface sitting behind the VLAN, yet inside the switch.186 Brocade IP Primer