Network Access Components — Cable Run CTS1305C

Slide 1 of 14  |  CTS1305C  |  Week 1
Network Access
Components
NICs, Ethernet, switches, cabling, and connectors — the physical foundation.
A new office needs network drops in 30 cubicles. You need to specify cable categories, connector types, and switch port counts. Making the wrong choice means pulling cable twice. This presentation gives you the knowledge to get it right the first time.
14 Slides Week 1 Layer 1 & Layer 2 Physical Access
Slide 2 of 14
Network Interface Cards (NICs)
The gateway between a device and the network.
COMPUTER NIC AA:BB:CC:DD:EE:FF Ethernet / Wi-Fi SWITCH Forwards frames using MAC addresses Network
What It Does
Converts data between the computer's bus and network signals (electrical, optical, or radio). Every NIC has a unique MAC address.
Form Factors
Built-in (onboard), PCIe expansion card, USB adapter. Servers often have multiple NICs for redundancy and load balancing.
Speeds
100 Mbps (Fast Ethernet), 1 Gbps (Gigabit, most common), 10 Gbps, 25/40/100 Gbps (data center). Auto-negotiation selects the best speed.
Slide 3 of 14
MAC Addresses — Physical Addressing
Every network interface has a unique 48-bit hardware address.
MAC ADDRESS FORMAT AA:BB:CC OUI (Manufacturer) : DD:EE:FF Device Unique ID 48 bits total = 6 bytes = 12 hex characters
OUI (First 3 Bytes)
Organizationally Unique Identifier assigned by IEEE. Identifies the manufacturer: 00:50:56 = VMware, 00:1A:2B = Cisco, etc.
Device ID (Last 3 Bytes)
Assigned by the manufacturer. Combined with OUI, creates a globally unique address. Can be spoofed in software but not changed on the chip.
Special Addresses
FF:FF:FF:FF:FF:FF = broadcast (sent to all devices on the LAN). MAC addresses operate at Layer 2 and are only significant within the local network segment.
Slide 4 of 14
The Ethernet Frame
The Layer 2 container that carries data across the LAN.
Preamble 7+1 bytes Dest MAC 6 bytes Src MAC 6 bytes EType 2 bytes Payload (46-1500 bytes) Layer 3+ data FCS 4 bytes EtherType: 0x0800 = IPv4 | 0x86DD = IPv6 | 0x0806 = ARP
Key Points
The Ethernet frame minimum size is 64 bytes (runt frames are discarded). Maximum size is 1518 bytes (or 1522 with 802.1Q VLAN tag). The FCS (Frame Check Sequence) uses CRC-32 for error detection — corrupted frames are silently dropped, never corrected.
MTU
Maximum Transmission Unit for standard Ethernet is 1500 bytes (payload only). Jumbo frames extend this to 9000 bytes for high-throughput environments (storage networks, data centers).
Slide 5 of 14
Switches & the CAM Table
Layer 2 devices that learn MAC addresses and forward frames intelligently.
SWITCH CAM Table Port 1: AA:BB:CC:11:22:33 Port 2: DD:EE:FF:44:55:66 Port 3: 11:22:33:AA:BB:CC Learns by reading source MAC PC-A (Port 1) AA:BB:CC:11:22:33 PC-B (Port 2) DD:EE:FF:44:55:66 PC-C (Port 3) 11:22:33:AA:BB:CC
How Switches Learn
When a frame arrives, the switch records the source MAC and the port it came in on. This builds the CAM (Content Addressable Memory) table dynamically.
How Switches Forward
If the destination MAC is in the CAM table, the switch sends the frame only to that port (unicast). If unknown, it floods to all ports except the source (unknown unicast flood).
Slide 6 of 14
Hubs vs Switches
Collision domains and broadcast domains explained.
Hub (Layer 1)
Repeater with multiple ports. Receives a signal on one port and rebroadcasts it to every other port. All devices share the same collision domain. Only one device can transmit at a time (half-duplex). CSMA/CD required.
Obsolete in modern networks. Replaced by switches.
Switch (Layer 2)
Intelligent frame forwarding. Each port is its own collision domain. Full-duplex operation (send and receive simultaneously). Uses MAC address table to deliver frames only where needed. Much higher throughput.
Standard in all modern networks. 1 Gbps+ per port.
ONE COLLISION DOMAIN All share bandwidth SEPARATE COLLISION DOMAINS Each port = own domain
Slide 7 of 14
Copper Cable Media
Twisted-pair and coaxial — the most common physical media.
UTP (Unshielded Twisted Pair)
Most common LAN cable. Four pairs of color-coded wires twisted together. Twisting reduces electromagnetic interference (EMI). Used with RJ-45 connectors. Max length: 100 meters.
STP (Shielded Twisted Pair)
Same as UTP but with a foil or braided shield around each pair or the whole cable. Better EMI protection for industrial or high-interference environments. More expensive and harder to terminate.
COAXIAL CABLE Center conductor Insulating layer Braided shield + jacket Used for cable internet (RG-6), legacy networks (RG-58/Thinnet). Connectors: BNC, F-type.
Rule of Thumb
UTP copper cables have a 100-meter maximum distance limit. Beyond that, use fiber optic or install a switch/repeater. Cat6a supports 10 Gbps at the full 100m; Cat6 only does 10 Gbps up to 55m.
Slide 8 of 14
Cable Categories & Speeds
Choosing the right cable for the job.
Category Max Speed Max Distance Frequency Common Use
Cat 5 100 Mbps 100 m 100 MHz Legacy (obsolete)
Cat 5e 1 Gbps 100 m 100 MHz Residential, small office
Cat 6 10 Gbps 55 m (10G) / 100 m (1G) 250 MHz Enterprise standard
Cat 6a 10 Gbps 100 m 500 MHz Enterprise, data center
Cat 7 10 Gbps 100 m 600 MHz Shielded, high-interference
Cat 8 25/40 Gbps 30 m 2000 MHz Data center switching
Exam Tip
Cat 5e is the minimum for Gigabit Ethernet. Cat 6a is the standard choice for new installations because it supports 10 Gbps at the full 100-meter distance.
Slide 9 of 14
Fiber Optic Media
Light-based transmission for speed, distance, and immunity to EMI.
Single-Mode Fiber (SMF)
Tiny core (8-10 microns). Uses a laser light source. Carries one ray of light over very long distances. Up to 100+ km. Used for WAN links, campus backbones, ISP infrastructure.
Yellow jacket (standard color coding)
Multi-Mode Fiber (MMF)
Larger core (50-62.5 microns). Uses LED light source. Multiple rays bounce through the core. Shorter distances: up to 550m (OM3) or 400m (OM4 at 10G). Lower cost.
Orange or aqua jacket (OM3/OM4)
FIBER ADVANTAGES OVER COPPER No EMI/RFI Longer distances Higher bandwidth Harder to tap
Slide 10 of 14
Network Connectors
Know which connector goes with which cable type.
RJ-45
8-pin modular connector for UTP/STP Ethernet cables. The most common network connector. Used on Cat5e, Cat6, Cat6a.
RJ-11
6-pin connector (2 or 4 wires used). Phone lines and DSL. Smaller than RJ-45 — do not confuse them.
SC (Subscriber)
Square push-pull fiber connector. Snap-in design. Common in enterprise and telco environments. Single or duplex.
LC (Lucent)
Small form-factor fiber connector (half the size of SC). Most popular in modern data centers and SFP/SFP+ transceivers.
ST (Straight Tip)
Round, bayonet-style twist-lock fiber connector. Legacy but still found in older installations. Single fiber per connector.
F-Type / BNC
F-type: screw-on coaxial connector (cable TV/internet). BNC: twist-lock coaxial (legacy Thinnet, test equipment, CCTV).
Slide 11 of 14
T568A & T568B Wiring Standards
Two pinout patterns for terminating RJ-45 connectors.
T568A 1: Wht/Grn 2: Green 3: Wht/Org 4: Blue 5: Wht/Blu 6: Orange 7: Wht/Brn 8: Brown Government / residential standard T568B 1: Wht/Org 2: Orange 3: Wht/Grn 4: Blue 5: Wht/Blu 6: Green 7: Wht/Brn 8: Brown Commercial / enterprise standard (most common)
Straight-Through vs Crossover
Straight-through: same standard on both ends (A-A or B-B) — connects unlike devices (PC to switch). Crossover: A on one end, B on the other — connects like devices (switch to switch). Note: most modern devices support Auto-MDIX and handle this automatically.
Slide 12 of 14
Structured Cabling
The organized infrastructure behind every professional network.
MDF Main Distribution Facility Core switches Demarcation point Backbone IDF Floor 1 Access switches Patch panels IDF Floor 2 Access switches Horizontal Work Area (wall jacks to devices) Patch cables, RJ-45 outlets Work Area (wall jacks to devices) Patch cables, RJ-45 outlets
MDF
Main Distribution Facility. The central wiring closet that houses core switches, routers, and the demarcation point (demarc).
IDF
Intermediate Distribution Facility. Per-floor or per-wing closets with access-layer switches connected to the MDF via backbone cabling.
Horizontal Cabling
Runs from the IDF to wall jacks in the work area. Typically Cat6/6a copper, max 90m (plus 5m each end for patch cables = 100m total).
Slide 13 of 14
Collision & Broadcast Domains
Two concepts that define network segmentation at Layer 1 and Layer 2.
Collision Domain
A network segment where simultaneous transmissions collide. Hubs: all ports share one collision domain. Switches: each port is a separate collision domain. Routers: each interface is a separate collision domain.
Broadcast Domain
A network segment where a broadcast frame (FF:FF:FF:FF:FF:FF) reaches all devices. Hubs and switches forward broadcasts to all ports. Routers stop broadcasts — each interface is a separate broadcast domain.
HUB 1 collision domain 1 broadcast domain SWITCH N collision domains (per port) 1 broadcast domain ROUTER N collision domains (per intf) N broadcast domains (per intf)
Why It Matters
Large broadcast domains create excessive traffic (broadcast storms). VLANs on a switch break up broadcast domains without needing separate physical routers — one of the most important network design techniques.
Slide 14 of 14
Summary & Key Takeaways
Everything you need to remember from this presentation.
1 NICs connect devices to the network. Each has a unique 48-bit MAC address (OUI + Device ID).
2 Ethernet frames carry data on the LAN: Dest MAC, Src MAC, EtherType, Payload (46-1500 bytes), FCS.
3 Switches learn MAC addresses via the CAM table and forward frames only to the correct port. Each port = 1 collision domain.
4 UTP copper cables use RJ-45 connectors and have a 100m max distance. Cat6a supports 10 Gbps at full distance.
5 Fiber: SMF (long distance, laser, yellow) vs MMF (short distance, LED, orange/aqua). Connectors: SC, LC, ST.
6 T568B is the most common wiring standard. Same on both ends = straight-through. A+B = crossover.
7 Structured cabling: MDF (core) to IDF (floor) via backbone; IDF to work area via horizontal runs.
For our office build-out: specify Cat6a UTP with RJ-45 to each cubicle, T568B termination, a 48-port managed switch in each IDF, and fiber backbone to the MDF. Label everything. Document everything.