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Which ports are designated ports?
The Designated Port is the port that has the lowest Path Cost on a particular Local Area Network (LAN) segment. Each segment has a single port that is used to reach the Root Bridge (Root Switch) called Designated Port. A Root Port can never be a Designated port.
What is the total length of the port ID in STP?
Each port of a Switch has a Spanning Tree Port Priority value associated with it, which is equal to 128 by default. Spanning Tree Port ID is formed by adding the 4-bit port priority value (the default value of 128) to 12-bit interface identifier (total 16 bits).
What is the difference between root port and designated port?
Root Port is a single selected port on a Switch, other than Root Switch, with least Path Cost to reach the Root Bridge. The Designated Port is the port that has the lowest Spanning Tree Path Cost on a particular Local Area Network (LAN) segment.
What port is the root port?
The important Latin root word port means ‘carry. ‘ Some common English words that use this root include import, export, deport, and report. An easy way to remember this word root is through the word portable, which is something that is easily ‘carried’ from one place to another.
What is port ID in STP?
Port ID is a logical interface identifier configured to participate in the STP instance. AFAIK it consists of port priority and port index. If BPDUs have the same Root Bridge ID, the same path cost to the Root and the same Sending Bridge ID (multiple links between two switches) then Port ID is used as a tie-breaker.
How is the designated port determined in STP?
In order to avoid loops, the non-designated port on the other end of the link is placed in blocking state. The designated switch is determined based on the following criteria: the switch with the lowest cost to reach the root becomes the designated switch on that link.
How to select designated port for spanning tree?
The port on the Switch which has better Spanning Tree Path Cost (omnisecu.com.SW3) is selected as the Designated port and other end of the Designated Port is the Non-Designated Port.
Is the non designated port the designated port?
That switch is called the designated switch and its port is known as the designated port. In order to avoid loops, the non-designated port on the other end of the link is placed in blocking state.
How is the cost of a root port determined?
If more than one link connects to the root bridge, then a port cost is determined by checking the bandwidth of each link. The lowest cost port becomes the root port. if multiple links have the same cost, the bridge withe the lower advertising Bridge ID is used. Since multiple links can be from the same device, the lowest port number will be used.