1. A method to share a communication link established between parser logic in a network adapter of a network processor and an external coprocessor, with processors in the network processor to request that a process be executed on said external coprocessor, said method comprising: a processor in the network processor sending request data and a command to request mailbox registers of the network adapter connected to the external coprocessor, wherein the request mailbox registers comprise a first request mailbox register that receives a command and an address and a second request mailbox that receives request data; sending the request data to the external coprocessor; and receiving response data and a response ready flag in response mailbox registers of the network adapter, wherein the response mailbox registers comprise a first response mailbox register that receives the response flag and a second response mailbox register that receives the response data; and the processor in the network processor reading the response data received in the response mailbox registers.