GATEWAY

• INTERNETWORKING TECHNOLOGIES

GATEWAY:
•A device that connects networks is called a gateway.
•Gateways provide a communication path so that data can be exchanged between networks.
•Operate at the transport layer and higher
•Protocol converter
•Much more complex than a router
• May provide protocol conversion
• For connecting internetworks
• Keeps sophisticated routing tables
• Operates well in a heterogeneous environment
• Large buffer space
• Can control traffic flow

https://docs.google.com/viewer?a=v&q=cache:LjXw9KjlhF0J:cis.bentley.edu/jgorgone/cs340/C/pdf/interconnect.pdf+&hl=en&pid=bl&srcid=ADGEESjZqjU_tOK_VtQTUbzl0TzFo_EhxOOV6eD6iVGX0Wt42lxE6ngbsUOUUgsAvPH3LWMWgpH_ZvYLQePeLpCLtBIXe0WkBR7Ki9ftSF_n6_naqPZiwx6z8qPvxQU10M9_uxDzf0R2&sig=AHIEtbThB3Z1YQPB6TqRCTV6qnawZ57q_A

• Gateways: 

Connecting Networks Above the Network Layer

• Gateways connect dissimilar networks; networks that do not share a common physical, data link, or network layer protocol
– A gateway can connect two or more networks above the network layer of the OSI model
• A gateway reconciles differences between the networks it connects and serves as a protocol converter
• In some instances, a complete network or WAN service may serve as a gateway between two networks

https://docs.google.com/viewer?a=v&q=cache:FLDLvVwOJ1EJ:userfs.cec.wustl.edu/~t82531a/ch13_PPT.ppt+&hl=en&pid=bl&srcid=ADGEESiBldY75YIEUdwJ28pXtAA6S2Af16t4BTX83TkDY1n6XYYaaWivSCMNx8g25CWZGwkIA787Gn9GGqlCz_MYkxH-8b4YG8p5mJgB1V2Cx7eBk_l4LmmMYToJH_AHG23cWW-hAYLS&sig=AHIEtbT8Im2bqnZx0WUn49jKJdTFQ_fkaw

Deterministic Finite Automata

• Deterministic Finite Automata

Given a state and a symbol, the next state is “determined”.

https://docs.google.com/viewer?a=v&q=cache:CnIhJXltnSAJ:https://courses.engr.illinois.edu/cs373/Lectures/lec02.pdf+&hl=en&pid=bl&srcid=ADGEESjbVJuZkjvw9Vd7-Y04m6eLDfdt4-VC42o7uvlP5oGFE27s4amdz8Y6r-9WYq_qKxPKb5Gxl9WaJfb_ROTM0Dm6FB-Y9NUJui9m1-RqfrGXepW3uSweDtZsOPMgMcb2IANtChfg&sig=AHIEtbSRmjiyMVyP4Z5BzzLEMIJqWvyluQ

State-transition diagrams

State-transition diagrams
In a state diagram the starting state is denoted by a circle with an “incoming arrow” and an accepting state is denoted by a double circle.

https://docs.google.com/viewer?a=v&q=cache:pNTot0ra-aEJ:research.cs.queensu.ca/home/cisc223/2013w/moni/m2.pdf+&hl=en&pid=bl&srcid=ADGEEShE2PTVOg4vQrI6-WKlf50OAXw9Ou0UOkpS1N8fYFoQ_ZkrFwZvgLTUtxEHw100kM0_wDaTh3INeyKzmdmnimFdm-riP6xMwpSvhy0-nPWf2Pq-MKnRLTIN9sK4u7kKwhjkxWW6&sig=AHIEtbSfQzHH1GN-LDYM6wqKV5mFdBSo8Q