The amount of dissolved gases in the magma can also affect it's viscosity, but in a more ambiguous way than temperature and silica content. When gases begin to escape (exsolve) from the magma, the effect of gas bubbles on the bulk viscosity is variable.
What is a firewall? A firewall is a system designed to prevent unauthorized access to or from a private network. You can implement a firewall in either hardware or software form, or a combination of both. Firewalls prevent unauthorized Internet users from accessing private networks connected to the Internet, especially intranets.
Mostly, however, the function of firewalls are to screen activities in order to protect a network. Summary: 1. A router transports data between networks; a firewall screens data that is to be sent across a network. 2. Routers are usually connected to at least two networks; a firewall operates from a designated computer, separate from the network, to deter incoming requests from reaching private network resources.