Packets are assembled together at the end despite the order they arrive in
Network Hardware
Makes network connectivity possible
Starts from NIC or Ethernet adapter
Network travels through hubs, switches, routers, and bridges (also physical units, talked about next unit)
Efficient network design requires a thorough understanding of these devices and possible config options
Hard to have problems with NICs because they are designed simply
Repeaters and Hubs
Going from least intelligence to most intelligence
Repeaters
Operate in Physical OSI model layer
No means to interpret data
Regenerate signal
Hub
Repeater with more than one output port
Typically contains multiple data ports
Bridges
A connectivity devices that operates at Data Link layer (Layer 2)
Reads header info to forward packets according to their MAC addresses
Switches
Two modes for switches
store-and-forward mode
Switch reads entire data frame into its memory and checks for accuracy before transmitting it
More time consuming but more accurate
cut-through mode
Switch reads frame’s header then decides where to forward the data before it receives the entire packet
Faster but less accurate
A connectivity devices that logically subdivides a network into smaller, individual collision domains
Operates at Data Link layer (layer 2)
Everything done in one device: hub, bridge
VLAN
Virtual Local Area Network
Local Area Network
Metro Area Network
Wide Area Network
Storage Area Network
Personal Area Network
Buddy Area Network
VLAN – A network within a network that is logically defined by grouping it’s devices’ switch ports in the same broadcast domain
Advantages:
Flexibility
Router
Multiport device operates at Layer 3 of OSI model and uses logical addressing information to direct data between networks or segments
Routers can connect dissimilar LANs and VLANs running at different transmission speeds using a variety of Network layer protocols
Determines the best path between nodes (OSPF) based on traffic congestion, available versus unavailable routes, load balancing targets, and other factors
Characteristics
Intelligence
Tracks node location
Determine shortest, fastest path between two nodes