Computer Network Gateways
By Stephen Bucaro
When networks with different protocols, such as Ethernet and Token Ring need to be connected
together, this requires reconstruction of the data packets. To do this, information from above
the network layer is required. A gateway is a device that can function at all seven layers of
the OSI model. A gateway can connect a LAN to a WAN, a LAN to a mainframe, translate protocols,
or convert transmission media.
A router that connects a local subnet to other networks is called a "default gateway".
A gateway that connects a LAN to the Internet is called a "proxy server" when it receives all
requests for Internet access from the LAN and routes them to the Internet. A gateway that
connects a LAN to the Internet is called a "firewall" when it provides security and protection
against external intrusions.
More Networking Protocols and Standards:
• Video - Network Layer (Layer 3) of OSI Networking Model
• Networking and Internet Standards Organizations
• A Simple Description of the IPv6 Header and Datagram
• IPv6 Neighbor Discovery Protocol (NDP)
• TCP/IP Protocol Suite
• The OSI Network Layer
• Session Border Controllers - More Than Just a Voice Firewall
• The OSI Physical Layer
• Understanding IP Routing
• IP version 6 (IPv6) Advantages and Implementation