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Q-in-Q Tunneling

Q-inQ Enables the Service Provider to carry and transport the customer VLANs across the provider switches. When the Service Provider carries VLANs from multiple customers across their network infrastructure, one of the potential problem can be that the customer VLAN number is already being used in the service...
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Private VLANs

Using Private VLANs provides a very elegant solution to two of the most challenging problems in an ISP based switched network 1. Using Private Vlans can delay the VLAN exhaustion when you are almost out of the entire VLAN space. This can possibly happen when you are an...
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MSTP (802.1S)

Multiple Spanning Tree Protocol With Per Vlan Spanning Tree protocol, you can have a different spanning tree topology per Vlan, with Root Switch for one vlan on a switch and Root Switch for another vlan on another switch. If you have a large number of vlans then each...
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Rapid Spanning Tree (RSTP)

RSTP (802.1w) Rapid Spanning Tree Protocol RSTP is backward compatible with classic STP (802.1d) RSTP has faster convergence than STP. Introduces new simplified Port States and Port Roles. The Timers in RSTP are replaced on a Synchronization Process which is also called as the Proposal and Agreement Process....
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Few notes on Spanning Tree Operations

Default Behavior in STP (802.1D) In Spanning Tree Protocol, the first step is to choose a root bridge for a vlan. Root Election isĀ  Based on Bridge Priority the tie breaker is Mac address when the Bridge Priority on both the switches is equal. In PVST the ext-sys-id...
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