Networking Devices
Hubs
• Layer 1 device
• Repeats signal
• Single Broadcast Domain
• Single Collision Domain
• Forwards bits out all ports
except the received
• Less than $30 not often a
solution
Bridges
• Layer 2
• Builds a Learning Table using
MAC addresses
• Software-based decisions are
standard which is slower than
Switching
• Low port density
• Around $50 not often a solution
Switches
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Layer 2
Single Broadcast Domain
Each port is a Collision Domain
Builds a MAC or CAM table and forwards
out destination port
Frames are created and forwarded at this
layer
ASICs (Application-Specific Integrated
Circuits) hardware decisions for speed
Options are line card (Layer 3), Modular
or fixed (SFPs), White Box or Common
Vedor
Access or Distribution. $100 - $10,000+
Routers
• Layer 3
• Each port is a Broadcast Domain
• Forwards Packets between
Networks using IP addresses
• Uses Routing Protocols and Static
Routes to build Routing Tables
• Options are line card (40Gb current
cross-connects), QSFPs are $400+,
• Core, Branch, Campus or Service
provider. $100 - $20,000+
Wireless AP
• Layer 2
• Shared Bandwidth (Full-Duplex
“like” with dual antennas)
• 2.4 and 5.0 GHz common
• Channels 1,6 and 11 do not overlap
and can assist with interference
caused by wireless phones etc.
• Avoidance must be used (CSMA/CD
for wired vs CSMA/CA for wireless)
• Commonly built into Home
modem/gateway. $50 - $200
Gateway
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Connects LAN to Service Provider
Firewall and Proxy capabilities
Performs NAT
Home gateways perform NAT,
Firewalls, can separate the DMZ, Portforwarding. Cost $50 - $200
• Data Center gateways are high
capacity routers capable of 40Gb or
100Gb cross-connects to the ISP. High
capacity backbone routers such as
Cisco 7609. Cost depends on line
cards and modular-pluggable chosen.
$2,000 - $20,000++
Firewall
• Can operate at any layer depending
on how security is implemented
• Monitors/Filters incoming traffic
• Designed to protect devices
• Packet inspection, Packet filtering
and Application firewalls are
common
• Vendors Palo Alto, Checkpoint, F5
and Cisco
• Depends on vendor capabilities
and options. $200 - $20,000