update to 05.Ethernet Lan Switching

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---
id: 1771825730-VZFA
aliases:
- 02. Interfaces and Cables - CCNA
tags:
- CCNA
---
# Interfaces and Cables
Front of a switch example phrase above the interfaces
10/100/1000 Base-T Ports ( 1 -24) - Ports are Auto MDIX
## [[RJ-45]]
Registerred Jack
## Etrhernet
Etrhernet is a collection of network protocols/standards.
## Network Protocols
Why do we need network protocols
For Industry standard that everybody follows
## [[Bits]] and [[Bytes]]
it a value represented by 0 and 1
a bytes is a series of 8 bits
Speed is measured in bits per second (kbps, Mbps, Gbps, etc) not bytes per seconds.
However for [[Hard drives]] we count the bytes
1 kilobit (kb) - 1,000 bits
1 megabit (Mb) - 1,000,000 bits
1 gigabit (Gb) - 1,000,000,000 bits
1 terabit (Tb) - 1,000,000 bits
## Etrhernet standards
- Defined in the IEEE 802.3 standard in 1983
- IEEE = Institute of Electrical and Electronics Engineers
### Copper Ethernet standard
| Speed | Common name | IEEE | Informal Name | Maximum Length |
| ------- | ------------------- | --------- | ------------- | -------------- |
| 10 Mbps | Ethernet | 802.3i | 10BASE-T | 100m |
| 100 Mbps| Fast Ethernet | 802.3u | 100BASE-T | 100m |
| 1 Gbps | Gigabit Ethernet | 802.3ab | 1000BASE-T | 100m |
| 10 Gbps | 10 Gig Ethernet | 802.3an | 10GBASE-T | 100m |
#### BASE T
Base = refers to baseband signaling
T = twitsted pair
### UTP Cables
Unshielded Twisted Pair
Twisted mean that there sensitive against [[EMI]] Electronic Magnetic Interference
they got 8 pins
10Base-T and 100Base-T = 2 pairs (4 wires)
1000Base-T and 10GBase-T = 4pairs (8 wires)
#### UTP Cables (10Base-T, 100 Base-T)
Full-Duplex transmission
Both devices can send and received data at the same. no colission while occur
##### Straight-through cable
Transmit 1 - 1 Receive
(TX) 2 - 2 (RX)
Recieve 3 - 3 Transmit
4 4
5 5
(RX) 6 - 6 (TX)
7 7
8 8
##### Crossover cable
Transmit 1 - 3 Transmit
(TX) 2 - 6 (TX)
Recieve 3 - 1 Receive
4 4
5 5
(RX) 6 - 2 (RX)
7 7
8 8
##### Chart
| Device Type | Transmit (TX) Pins | Recieve (RX) Pins |
| ----------- | ------------------ | ----------------- |
| [[Router]] | 1 and 2 | 3 and 6 |
|[[Firewall]] | 1 and 2 | 3 and 6 |
| [[PC]] | 1 and 2 | 3 and 6 |
| [[Switch]] | 3 and 6 | 1 and 2 |
##### Auto MDI-X
allows devices to automatically detect and adjust the the pins for transmiting data prevent colissions
#### UTP Cables (10Base-T, 100 Base-T)
##### Straight-through cable
Each pair is bidirectional
the pair are
1 and 2
3 and 6
4 and 5
7 and 8
## Fiber-Optic Connection
[[SFP]] Transceiver Small-Factor Pluggable for Fiber Optics cable
Send light over glass fiber
TX - RX
RX - TX
there are 4 layers for this cable
1 : the fiberglass core itself
2 : cladding that reflects light
3 : a protective buffer
4 : the outer jacket of the cable
single-mode and multimode fiber
### Multimode fiber
- Core diameter is wider than single mode fiber.
- Allow mutiple angles (modes) of light waves to enter the fiberglass core
- Allows longer cables tha [[UTP]] but shorter cables than single-mode fiber.
- cheaper than single-mode fiber (due to cheaper LED-based SFP transmitters)
### Single-Mode Fiber
- Core diameter is narrower than multimode fiber
- Light enters at a single angle (mode) from alaser-based transmitter
- Allows longer cables than both UTP and multimode fiber
- More expensive than multimode fiber (due to more expnesive laser based transmitters)
### Fiber-Optic cables standards
| Speed | Cable Type | IEEE | Informal Name | Maximum Length |
| ------- | ------------------- | --------- | ------------- | ---------------- |
| 1 Gbps | multi or single-mode| 802.3z | 1000BASE-LX | 550m(MM) 5km (SM)|
| 10 Gbps | Multi-mode | 802.3ae | 10GBASE-SR | 400m |
| 10 Gbps | Single-Mode | 802.3ae | 10GBASE-LR | 10km |
| 10 Gbps | Single-Mode | 802.3ae | 10GBASE-ER | 30km |
## UTP vs Fiber-Optic Cabling
- UTP
- Lower cost than fiber optic.
- Shorter Maximum distance than fiber0-optic (100m).
- Can be vulnerable to EMI
- RJ45 ports used with UTP are cheaper than SFP ports.
- Emit (leak) a faint signal outside of the cable, which can be copied (= security risk)
- Fiber-Optic
- Higher cost than UTP.
- Longer maximum distance than UTP.
- No vulnerability to EMI.
- SFP ports are more expnsive than RJ45 ports (singl-mode is more expensive than multimode).
- Does not emit any signal outside of the cable (=no security risk)