Greetings all,

Back at it and not wasting time at all. I mean eh, it is 2024 right?! Goals were drafted and now the skill must be crafted. In the prior post, I spoke a bit about the world of networking and the basics. Things such as switches and routers were discussed as well as type of networks. Now I go a bit more into the interfaces and cable side of things. Yes, many would say to skip this part, but in my case I want to be a master of the field cybersecurity. I also have a background in electronics so a bit of this is a review well needed. Well, let's not wait and get into more of the notes surrounding networking. Specifically Ethernet and Fiber-optic cable will be reviewed with much in addition. Ok... I'll hush. LOL.

What are bits and bytes?

Bit:

• A value represented by 0 and 1. When communicating over copper cable, the data is sent is interpreted by the receive device using 0 or 1.

Byte:

• A series of 8 bits. 8 bits = 1 Byte.

Remember, speed is measured by bits per second. Kbps, Mbps, Gbps, etc. Never bytes per second.

• 1 Kb = 1,000 bits
• 1 Mb = 1,000,000 bits
• 1 Gb = 1,000,000,000 bits
• 1 Tb = 1,000,000,000,000 bits

What is Ethernet?

• A collection of network protocols and standards.

What is RJ-45?

• RJ-45:( Registered Jack- 45 )ie: Ethernet Connection

What are Ethernet Standards?

• IEEE 802.3 standard in 1983. (Institute of Electrical and Electronics Engineers)

• ie: 10-BASE-T, 100BASE-T, 1000BASE-T, 10GBASE-T)

• Be sure to look up the standards listed above.

Listed in the standards are the following:

• Speed
• Common Name
• IEEE Standard
• Informal Name
• Max Length

What are UTP Cables?
(ie: Cat 6 cable )

• UnShielded Twisted Pair (No metallic shield which it vulnerable to electrical interference)
• The Twist protects against EMI (Electromagnetic Interference)
• Lower cost than fiber-optic
• Shorter max than fiber-optic (up to 100 meters)
• RJ45 ports usd with UTP are cheaper than SFP ports.
• Emit (leak) a faint signal outside of the cable which can give security risks.

What are Fiber Optic Cable?

• Sends light over glass fibers having one connection to send and one connection to receive.

Two Types of Fiber-Optic Cable are below:

Single-mode Fiber Optic Cables:

• core diameter is narrower
• light enters at a single angle mode from a laser based transmitter.
• allows longer cables than both UTP and multimode fiber.

• more expensive than multimode fiber (due to more expensive laser-based SFP transmitters)

• They use separate cable to send and receive connections

  1. fiberglass core
  2. cladding that reflects light
  3. a protective buffer
  4. the outer jacket of the cable.

Multi-mode Fiber Optic Cables (Cheaper than Single Mode):

• core diameter is wider than single-mode fiber
• allows multiple angles (modes) of light waves to enter the fiberglass core.
• allows longer cables than UTP, but shorter cables than single-mode fiber.
• cheaper than single-mode fiber due to cheaper LED-based SFP transmitters.
• Does NOT emit any signal outside of the cable (=no sec risk)

What is a SFP Transceiver?

• (Small form-factor pluggable): Connect a fiber optic cable to them.

Resources:

What is Ethernet?

What are Ethernet Standards and Protocols?

Straight-Through vs Crossover Cable

What are Fiber-Optic Cable?