# Plug Chain Network
The Plug Chain network is an internet of blockchains intended to provide a technology foundation that facilitates construction of distributed business applications.
The Plug Chain network is part of the larger Cosmos network -- all zones in the network would be able to interact with any other zone in the Cosmos network over the standard IBC protocol. We will provide an innovative solution that supports a whole new business scenario by introducing a layer of service semantics into the network, increasing the scale and diversity of the Cosmos network.
# Plug Chain
At the "center" of the Plug Chain network is a blockchain known as the Plug Chain Hub, which is a Proof-of-Stake (PoS) blockchain built on Cosmos SDK and Tendermint. It will be the first regional hub to connect the Cosmos Hub. The Plug Chain hub is equipped with a service protocol that coordinates on-chain transaction processing with off-chain data processing and business logic execution. We have also enhanced the IBC protocol to facilitate cross-chain invocation of those off-chain services, if so desired.
The service protocol and enhanced IBC protocol could eventually be contributed back into Cosmos SDK, allowing SDK users to develop blockchains that are compatible with the Plug Chain network.
Client-facing, programming language specific SDKs will also be available to make it easy to provide and consume off-chain services within the Plug Chain network.
# Plug Chain Token
The Plug Chain hub has its own native token, called pc , which has three roles in the network.
** Mortgage. ** Similar to the ATOM token in the Cosmos Hub, the pc token will be used as a collateral token to protect the safe operation of the PoS blockchain.
- **transaction fee. ** pc tokens will also be used to pay for all transactions in the Plug Chain network.
**Service charge. ** Service providers in the Plug Chain network need to charge service fees in units of pc tokens.
The Plug Chain network will eventually support all whitelisted fee tokens, which can be used to pay transaction fees and service fees.