A router forwards data packets between computer networks to create an internetwork. It reads address information to determine a packet's destination and uses its routing table to direct the packet through networks until it reaches its destination node. A switch receives messages and transmits them only to the intended device, making it more intelligent than a hub which broadcasts to all devices. Common networking protocols include TCP/IP for addressing and transporting data, DNS for domain names, and HTTP/HTTPS for web protocols. Ethernet cables like Cat5e and Cat6 can support speeds up to 1 Gbps and 10 Gbps respectively. The document also discusses WiFi versions and configurations, powerline networking, firewalls, and network-attached storage (NAS).

1. Tech Blast: Networks
Michael Sauers
Tech Rodeo
Doane College, 26-28 July 2012

3. Router
A router is a device that forwards data
packets between computer networks,
creating an overlay internetwork. A
router is connected to two or more data
lines from different networks. When a
data packet comes in on one of the lines,
the router reads the address information
in the packet to determine its ultimate
destination. Then, using information in
its routing table or routing policy, it
directs the packet to the next network on
its journey. Routers perform the "traffic
directing" functions on the Internet. A
data packet is typically forwarded from
one router to another through the
networks that constitute the
internetwork until it gets to its
destination node.

4. Switch
A switch is a telecommunication device
which receives a message from any device
connected to it and then transmits the
message only to that device for which the
message was meant. This makes the switch
a more intelligent device than a hub (which
receives a message and then transmits it to
all the other devices on its network.) The
network switch plays an integral part in
most modern Ethernet local area networks
(LANs). Mid-to-large sized LANs contain a
number of linked managed switches. Small
office/home office (SOHO) applications
typically use a single switch, or an all-
purpose converged device such as a
residential gateway to access small
office/home broadband services such as
DSL or cable internet.

5. Ethernet Cables
• Cat-5
– 10 or 100 Mbps
• Cat-5e
– Up to 1 Gbps
• Cat-6
– Up to 10 Gbps

6. Networking Protocols
• TCP/IP • SAMBA
– IP address – Used for communicating
– Internal vs. External between Linux &
– Dynamic (DHCP) vs. Windows computers on
Static a LAN
• DNS
– Domain Name Server
• HTTP/HTTPS

7. WiFi
• Versions
– b (up to 11 Mbps)
– g (up to 54 Mbps)
– n (up to 150 Mbps)
– ac (up to 866.7 Mbps)
• SSID
– Service Set Identifier
• Security
– WEP
– WPA

8. WiFi Continued
• Distance matters
• Channels
• Access Points /
Repeaters / Extenders

9. Power Line Networking
Power line communication
(PLC) is a system for
carrying data on a
conductor that is also
used for electric power
transmission.
200 or 500 Mbps

10. Firewall
A firewall can either be software-
based or hardware-based and is used
to help keep a network secure. Its
primary objective is to control the
incoming and outgoing network
traffic by analyzing the data packets
and determining whether it should
be allowed through or not, based on
a predetermined rule set. A
network's firewall builds a bridge
between an internal network that is
assumed to be secure and trusted,
and another network, usually an
external (inter)network, such as the
Internet, that is not assumed to be
secure and trusted.

11. NAS
Network-attached storage (NAS) is
file-level computer data storage
connected to a computer network
providing data access to
heterogeneous clients. NAS not only
operates as a file server, but is
specialized for this task either by its
hardware, software, or configuration
of those elements. NAS is often
made as a computer appliance – a
specialized computer built from the
ground up for storing and serving
files – rather than simply a general
purpose computer being used for the
role.

12. Thanks!
Michael Sauers
michael.sauers@nebraska.gov
diane.r.wells@nebraska.gov