JML Institute Online
LOCAL AREA NETWORKS:  JML-Lec14b
(Main sections:  This is the study material for the 3rd Quiz on this section.)
1.  Network Topologies:  Ethernet - Token Ring - etc. 
2.  LAN hardware devices & wiring, Maus, Hubs
3.  Protocols & communication. DSL etc.
4.  Bridges, Cisco Routers, Gateways, & T1-Multiplexors.  (jmlDVD#4) 
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BRIDGES: 
Spans networks at the MAC sublayer of Datalink (of OSI protocols)  A bridge can span if both ends agree to 802.2 LLC.  Bridges have several advantages.  They have filtering capabilities.  They allow various topologies. They increase the distance a network can span.

Spanning Tree Algorithm:
All bridges in multiple path network selects a root bridge based on priority or costs (speed etc.).  If no priority can be established a hop "tree" is used to determine shortest path from LAN to LAN. Each bridge has an address database which stores station addresses of all bridge in that network.

Source Routing:  The source computer sends a broadcast frame all routes to all rings.  This frame contains a blank buffer for bridges to fill in numbers for 2 rings and their own.  The receiving workstation send this 	info back to the source as a "road map" of the route it took.  Frames are forwarded across bridges if its information field equals the 2 ring numbers of the bridge. 

ROUTERS:  
Routers operate at the high network level of OSI.  They are well suited for networks with many paths where subnet don't have the same MAC level.   Their routing tables are used to exchange packette to find 	optimum paths. They can dissassemble and reassemble packett if the size differ.  They  are slower but more intelligent than bridges and utilizes complex algorithms.   Routers can create a firewall by not always replicating all messages that might flood the network like repeating packetts.  Dynamic Routers use one of these algorithms.

Distance Vector Algorithm: used by R.I.P. keeps a hopcount of the number of routers between source and the destination.
Link State Algorithm: Broadcast packetts describing its own links to other routers.  All other routers use this info to assemble its routing tables.

BROUTERS:  Are slower

CISCO ROUTERS:  Coming soon.  inc.

GATEWAYS:  
In the past IBM connected mainframes to workstations via cluster controllers  or directly connect with coaxial cable and IRMA boards connected to PCs with just a card with cluster emulation software in ROM.  Gateways boards still do emulate cluster controllers and perform protocol conversion at the application layer of OSI.  There are several ways to connect a gateway to a mainframe.  Gateways are used to connect networks of different architecture and uses all 7 levels of OSI.

T1'S:  Coming soon.  inc.
		
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assignment :
Search the internet for new networking protocols and write a 2 page summary of  your selection. 

EMAIL:  attach your assignment to your email. 
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