The primary purpose of a consensus mechanism in a blockchain network is to ensure that all nodes agree on the order and validity of transactions and blocks, thereby maintaining the integrity and consistency of the blockchain.

Proof-of-Work (PoW) is known for its simplicity and low computational requirements. It involves miners solving complex mathematical puzzles to validate transactions and add new blocks to the blockchain.

Proof-of-Stake (PoS) addresses the scalability limitations of Proof-of-Work by eliminating the need for intensive computation. Instead, it relies on validators who stake their cryptocurrency holdings to validate transactions and add new blocks to the blockchain.

In a Delegated Proof-of-Stake (DPoS) consensus mechanism, a select group of elected delegates is responsible for validating transactions and producing blocks. These delegates are chosen by the network participants based on their reputation, expertise, and stake in the network.

Proof-of-Authority (PoA) is often used in permissioned blockchain networks where identity and reputation are known. It relies on a set of pre-selected validators who are trusted to validate transactions and add new blocks to the blockchain.

Practical Byzantine Fault Tolerance (PBFT) is known for its high transaction throughput and fast block confirmation times. It is a consensus mechanism that can tolerate Byzantine faults, where nodes can behave arbitrarily and maliciously.

The primary challenge associated with Proof-of-Work (PoW) consensus mechanism is its high energy consumption. Mining new blocks requires significant computational power and electricity, which can lead to environmental concerns and high operating costs.

Proof-of-History (PoH) is designed to address the scalability limitations of Proof-of-Work (PoW) by introducing sharding. It involves generating a verifiable record of the passage of time to validate transactions and add new blocks to the blockchain.

The primary advantage of Delegated Proof-of-Stake (DPoS) consensus mechanism over Proof-of-Work (PoW) is reduced energy consumption. DPoS eliminates the need for intensive computation and relies on elected delegates to validate transactions and produce blocks.

Gossip Protocol is known for its ability to achieve consensus quickly and efficiently, even in large networks. It involves nodes exchanging information with their peers to propagate transactions and reach consensus on the state of the blockchain.

The primary challenge associated with Practical Byzantine Fault Tolerance (PBFT) consensus mechanism is its limited scalability in large networks. PBFT requires all nodes to communicate with each other, which can become computationally expensive and slow as the network grows.

Plasma is designed to improve the scalability of blockchain networks by introducing off-chain transactions. It involves creating child chains that are linked to the main blockchain, allowing for faster and cheaper transactions to be processed off-chain.

The primary advantage of Proof-of-Authority (PoA) consensus mechanism over other consensus mechanisms is faster transaction confirmation times. PoA relies on a set of pre-selected validators who can quickly validate transactions and add new blocks to the blockchain.

Proof-of-Trust (PoT) is known for its ability to achieve consensus without the need for a central authority or trusted third party. It relies on a reputation system where nodes are assigned a trust score based on their past behavior and interactions.