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

• 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

• Connects LAN to Service Provider • Firewall and Proxy capabilities • Performs NAT• Home gateways perform NAT, Firewalls,

can separate the DMZ, Port-forwarding. 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