BROCADE IP PRIMER

49FLinkPower50FConsole49F Link 50F1 3 5 7 9 1113 15 17 19 21 2325 27 29 31 33 3537 39 41 43 45 47Power1F 2F 3F 4F2 4 6 8 10 1214 16 18 20 22 2426 28 30 32 34 3638 40 42 44 46 4849FLinkPower50FConsole1 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 4849FLinkPower50FConsole1 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 4849FLinkPower50F49F Link 50FPower1F 2F 3F 4F49FLinkPower50FConsole1 3 5 7 9 1113 15 17 19 21 2325 27 29 31 33 3537 39 41 43 45 472 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 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 4849FLinkPower50FConsole1 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 9: Spanning Tree ProtocolVLAN 10Switch 1Root switchxSwitch 2Switch 4xxSwitch 3Using MST, you can configure Spanning Tree such that the Blocking links forone VLAN are the Forwarding links for the other (and vice versa). This way, allthe available links are being actively used. This provides greater bandwidth forboth VLANs.VLAN 20Switch 1xxSwitch 2Root switchSwitch 4xSwitch 3All we had to do is change a priority. This technique is referred to as STP LoadSharing. STP, by nature, is active/standby. When two or more paths are presented,one is chosen, and the others are disabled. With STP Load Sharing,you are taking advantage of STP's active/standby nature by making linksactive for some, and “standby” for others. It's a great way to get more out ofyour infrastructure.Topology GroupsMST is not necessarily the end-all solution for every infrastructure. For one,MST for every defined VLAN doesn't scale well. Running over 100 SpanningTree instances is very CPU and memory intensive. Plus, you could run out ofSpanning Tree instances before you run out of VLANs. Most chassis will allowup to 4,000 VLANs, but only 128 STP instances.One way to solve this problem is with Topology Groups. Topology Groups take agroup of VLANs and assign one instance of STP to it. Now, all of the VLANs inthe Topology Group have to share the same instance of STP. A Topology Groupcan contain as few or as many VLANs as you'd like.Each Topology Group has a Master VLAN. This VLAN is where your STP settingsare defined. Say, for example, you had three VLANs: 10, 30, and 50. You wantthese three VLANs to share the same STP instance, and you want to configurethat instance in VLAN 30.210 Brocade IP Primer