2.5 - Network Devices

Network Devices

Many different devices and components.

• All have different roles.

Some of these functions are combined together.

• Wireless router/switch/firewall.

Compare different devices.

• Understand when they should be used.

Routers

Routes traffic between IP subnets.

• Makes forwarding decisions based on IP address.

• When they are inside switches they are sometimes called “Layer 3 Switches”.

Often connects diverse network types.

• LAN, WAN, copper, fiber.

Switches

Bridging done in hardware.

• Application specific integrated circuit (ASIC)

• Forwards traffic based on data link address.

Many ports and features

• The core of an enterprise network.

• May provide POE (Power Over Internet)

Multilayer Switch

• Includes routing functionality.

Unmanaged Switches

Very few configuration options - plug and play.

Fixed configuration - no VLANs

Very little integration with other devices.

• No management protocols.

Low price point - simple is less expensive.

Managed Switches

VLAN support

• Interconnect with other switches via 802.1Q

Traffic prioritization.

• Voice traffic gets a higher priority.

Redundancy support

• STP ( Spanning Tree Protocol)

Port Mirroring

• Capture packets.

External management

• SNMP (Simple Network Management Protocol)

Access Point

Not a wireless router.

• A wireless router is a router and an access point in a single device.

An access point is a bridge.

• Extends the wired network onto the wireless network.

  • Makes forwarding decisions based on MAC address.

Patch Panels

Combination of punch-down blocks and RJ-45 connectors.

Runs from desks are made once.

• Permanently punched down to patch panel.

Patch panel to switch can be easily changed.

• No special tools - use existing cables.

Firewalls

Filters traffic by port number.

• OSI layer 4 (TCP/UDP)

• Some firewalls can filter based on the application.

Can encrypt traffic into/out of the network.

• Protect your traffic between sites.

Can proxy traffic.

• A common security technique.

Most firewalls can be a layer 3 devices (routers)

• Usually sits on the ingress/egress of a network.

Power Over Internet (PoE)

Power provided on the Ethernet cable.

• One wire for both network and electricity.

• Phones, cameras, wireless access points.

• Useful in difficult-to-power areas.

Power provided at the switch.

• Built-in power - Endspans

• In-line power injector - Midspans

PoE Switch

Power over Ethernet

• Commonly marked on the switch or interfaces.

Types of PoE

PoE

PoE+

PoE++

Compare the device with the switch support.

• PoE+ won’t power a PoE++ device.

PoE

The original PoE specification.

Now part of the 802.3 standard.

15.4 watts DC power, 600 mA max current.

PoE+

Now also part of the 802.3 standard.

25.5 watts DC power, 600 mA max current.

PoE++

51 W (Type 3), 600 mA max current.

71 W (Type 4), 960 mA max current.

Cable Modem

Broadband

• Transmission across multiple frequencies.

• Different traffic types.

Data on the “Cable” network.

• DOCSIS (DATA Over Cable Service Interface Specification)

High-speed networking

• Speeds up to 1 GB are available.

Multiple services - Data, voice, video.

DSL Modem

Digital Subscriber Line - uses telephone lines.

Download speed is faster than upload speed (asymmetric).

• 10,000 foot limitation from central office.

  • Faster speeds may be possible if closer to the CO.

ONT

Optical Network Terminal - fiber to premises.

Connect the ISP fiber network to the copper network.

• Demarcation point (demarc) in the data center.

• Terminal box on the side of the building.

Line of responsibility.

• One side of the box is the ISP.

  • Other side of the box is your network.

NIC (Network Interface Card)

The fundamental network device.

• Every device on the network has one.

• Computers, servers, printers, routers, switches, phones tablets, cameras.

Specific to the network type - Ethernet, WAN, wireless.

Often built-in to the motherboard.

• Or added as an expansion card.

Contains the hardware address.

• MAC (Media Access Control) address.

• A unique hardware designation.