Networking Fundamentals: Local Networks
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The document outlines networking fundamentals, covering topics such as local area networks, internet protocols (TCP, UDP), and various networking models. It details the physical and data link layers, Ethernet types, collision domains, and addresses the logic of switches in a network environment. Additionally, it includes references for further reading on specific networking certifications and standards.
Networking Fundamentals: Local Networks
- 1. Andriy Berestovskyy 2017 ( ц ) А н д р і й Б е р е с т о в с ь к и й networking hour TCP UDP NAT IPsec IPv4 IPv6 internet protocolsAH ESP authentication authorization accounting encapsulation security BGP OSPF ICMP ACLSNAT tunnel PPPoE GRE ARP discovery NDP OSI broadcast multicast IGMP PIM MAC DHCP DNS fragmentation semihalf berestovskyy Networking Fundamentals Local Networks
- 2. Networking Fundamentals ● Computer Networks ● Networking Models ● > Local Networks ● Internet ● IPv4 Routing ● Transport Protocols 2
- 3. Krakusa 11, 1st floor Local Area Network 3 Krakusa 11, 2nd floor Krakusa 11, 3rd floor How? Interconnects hosts within a limited area and has its network equipment and interconnects locally managed
- 4. Typical SOHO LAN 4 Internet Switch Access Point Router SOHO? Distance?
- 5. Small Office/Home Office (SOHO) — category of business that involves from 1 to 10 workers — Wikipedia 5
- 6. Building 1 Typical Corporate LAN 6 Corporate Network Floor 2 Floor 1 Distance?
- 7. Building 1 Typical Corporate Network 7 Corporate Network Building 2 Building 3 Building 4 Distance?
- 8. Ethernet Physical Layer 8 Application Presentation Session Transport Network Data Link Physical Frame Bits MAC Data FCS IP Data TCP Data Packet Segment Data 7 6 5 4 3 2 1 Hi! Salut!
- 9. Typical Ethernet Physical Layers 9 10 Mbps Speed 100 Mbps 1 Gbps Name 1 Gbps 10 Gbps Medium Distance 10BASE-T Twisted Pair 100 m 100BASE-T Twisted Pair 100 m 10 Mbps10BASE2 Coaxial Cable 100 m 1000BASE-T Twisted Pair 100 m 1000BASE-LX SM Fiber 5 km 10GBASE-LR SM Fiber 10 km 10 Gbps10GBASE-ER SM Fiber 40 km Ethernet Fast Ethernet 10 Gigabit Ethernet Gigabit Ethernet More?
- 10. Switch Ethernet Link Over a Twisted Pair 10 Host Cable RJ-45 Connector RJ-45 Connector RJ-45 Port RJ-45 Port
- 11. Switch Fast Ethernet Straight Cable 11 Host TX RX RX TX 1 2 3 6 Twisted Pair Twisted Pair 1 2 3 6 Host 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 Switch 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 MDI* MDI-X* * Media Dependent Interface (Crossover)
- 12. Host Fast Ethernet Crossover Cable 12 Host TX TX RX RX 1 2 3 6 Twisted Pair Twisted Pair 1 2 3 6 Host 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 Host 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 MDI MDI
- 13. Cable Usage? 13 Access Point Host Router Switch Hub Host Access Point Router Hub Switch
- 14. Cable Usage 14 Access Point CrossHost Router Switch Hub Host Cross Access Point Cross Router Straight Hub Switch Cross Cross Cross Cross Cross Cross Cross Cross Cross Cross MDI MDI-X Straight Straight Straight Straight Straight Straight Straight Straight Straight Straight Straight MDI-X
- 15. Gigabit Ethernet Cable Pinout 15 Host 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 Host 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 MDI MDI Host 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 Switch 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 MDI MDI-X
- 16. Host BHost A 10BASE2 Physical Layer 16 Data Data 0 V +1 V -1 V Data 1 0 1 0 0 1 1 1 0 0 1 Source: https://en.wikipedia.org/wiki/Manchester_code ● Manchester encoding ● Half duplex Duplex? BNC T-Connector BNC T-Connector Why?
- 17. Half Duplex Communication 17 send or receive :( or What if both?
- 18. Collision 18 Host A Host B
- 19. Collision occurs when several demands are made simultaneously on equipment that can handle only one at a time — Wikipedia 19
- 20. Collision domain — section of a network where data packets can collide with one another — Wikipedia 20 Broadcast domain?
- 21. Shared Medium Collision Domain 21 Host A Host B Host C Host D 10Base2 Ethernet over Coaxial cable Collision domain? C B A D 1 1
- 22. Collision Domain Shared Medium Collision Domain 22 Host A Host B Host C Host D C B A D 2 10Base2 Ethernet over Coaxial cable 1 1 Solutions?
- 23. CSMA/CD Carrier-Sense Multiple Access with Collision Detection media access control method: 1. IF medium is not idle THEN goto 1 2. Start transmission + monitor for a collision 3. IF collision occurred THEN wait, goto 1 23
- 24. Repeater Hub TX Host A 10BASE-T Physical Layer 24 TX RX RX TX RX TX 0 V +1 V -1 V Data 1 0 1 0 0 1 1 1 0 0 1 ● Manchester encoding ● Half duplex Why? RX TX RX
- 25. Repeater Hub Collision Domain 25 Host A Host B Host C Host D Repeater Hub Collision domain? 10Base-T Ethernet over a Twisted Pair A B A C 1 1
- 26. Collision Domain Repeater Hub Collision Domain 26 Host A Host B Host C Host D Repeater Hub A B A C 1 1 A C A B 2 A C A B 2
- 27. Switch RX TX Host A 10GBASE-T Physical Layer 27 TX RX More info: https://en.wikipedia.org/wiki/Pulse-amplitude_modulation RX TX RX TX 0 V +1 V -1 V Data* 1 0 1 0 0 1 1 1 0 0 1 0 ● PAM-16 encoding* ● Full duplex Why? TX RX CPU 0000 * oversimplification! 0010 0100 0110 1111 1101 1011 1001 RAMRAM 1 1 1 1 1 1 0 1 0 0 0 1 0 1 0 0 1 1 1 1 0 1 1 1 1 0 0 1 1 0 0 0 What for?
- 28. Switch Collision Domain 28 Host A Host B Host C Host D Collision domain? A B A C 1 1
- 29. Switch Collision Domains 29 Host A Host B Host C Host D A B A C 1 A B 1 A C Switch eliminates collisions by breaking down collision domain 2
- 30. Collision Domain Switch RX TX Host A Switch Stores & Forwards 30 TX RX RX TX RX TX TX RX CPU RAMRAM A C A B Switch stores Ethernet frame in RAM and then forwards it Pros/Cons?
- 31. Ethernet Data Link Layer 31 Application Presentation Session Transport Network Data Link Physical Frame Bits MAC Data FCS IP Data TCP Data Packet Segment Data 7 6 5 4 3 2 1 Hi! Salut!
- 32. Ethernet Frame Format 32Source: https://en.wikipedia.org/wiki/Ethernet_frame Ethernet Frame Bits 2 1 7 Preamble, 7 octets Start of Frame, 1 octet 6 Destination MAC, 6 octets 6 Source MAC, 6 octets 4 Optional 802.1q (VLAN) Tag, 4 octets Ethertype, 2 octets 46-1500 4 Frame Check Sequence, 4 octets 12 Interframe gap, 12 octetsPayload, 46-1500 octets 72 — 1530 octets 64 — 1522 octets TrailerHeader
- 33. Optional 802.1q (VLAN) Tag 33 Payload ... MAC Destination MAC Destination MAC Source MAC Source Ethertype 0 32 14Bytes Frame Check Sequence Payload ... MAC Destination MAC Destination MAC Source MAC Source Ethertype 0 32 18Bytes Frame Check Sequence 0x8100 VIDPCP D PCP — Priority Code Point (Class of service) (3 bits) DEI — Drop Eligible Indicator (1 bit) VID — VLAN Identifier (12 bit) Protected by Frame Check Sequence
- 34. Ethernet MAC Address 34* OUI — Organizationally Unique Identifier 6 Destination MAC, 6 octets 6 Source MAC, 6 octets 4 46-1500 4 123456Intel 825992 789abcIntel I350 123456Cavium 2 2 Family Name First Name NIC IDOUI*2 24 bits 24 bits b7 0: globally unique 1: locally managed b6 0: unicast 1: multicast 654321 b5 b4 b3 b2 b1 b0
- 35. Ethernet Type 35 6 6 Ethertype, 2 octets 4 46-1500 4 1 Eth Type IPv4 IPv4 Payload Eth Ethertype = 0x8000 2 Eth Type IPv6 IPv6 Payload Eth Ethertype = 0x86DD
- 36. Per-VLAN Switch Logic 36 Host A Host B Host C Host D D A Why? PortMAC 1 2 3 4 MAC Table Learn!
- 37. 1A Per-VLAN Switch Logic 37 Host A Host B Host C Host D D A 1 PortMAC 1 2 3 4 MAC Table 2 1. Check Ethernet FCS 2. Add A to MAC table 3. No D in MAC table: ○ what to do?
- 38. 1A Per-VLAN Switch Logic 38 Host A Host B Host C Host D D A 1 PortMAC 1 2 3 4 MAC Table 2 D A D A 3 3 “Unknown unicast” D A 3 1. Check Ethernet FCS 2. Add A to MAC table 3. No D in MAC table: ○ send to all ports Problems?
- 39. 1A Per-VLAN Switch Logic 39 Host A Host B Host C Host D 4 Port D MAC 1 2 3 4 MAC Table 2 A D 1 1. Check Ethernet FCS 2. Add D to MAC table 3. A in MAC table: ○ send to port 1 A D 3
- 40. 1. Receive frame, check Ethernet FCS 2. Add/update source MAC in MAC table 3. If multicast bit is set: a. forward to all ports, but the source 4. If destination is in MAC table: a. forward to the specific port 5. Else, forward to all ports Per-VLAN Switch Logic Summary 40
- 41. Local Networks Checklist 1. LAN? 2. Ethernet? 3. Ethernet physical layers? 4. Straight through vs crossover cables? 5. Duplex? 6. Collision? 7. Collision domains for hub, switch? 8. CSMA/CD? 9. Ethernet header? 10. 802.1q tag? 11. Switch logic? 41
- 42. References 1. Kevin Wallace. CCNP Routing and Switching ROUTE 300-101 Official Cert Guide. Cisco Press, 2014 2. David Hucaby. CCNP Routing and Switching SWITCH 300-115 Official Cert Guide. Cisco Press, 2014 3. RFC 1122. Requirements for Internet Hosts — Communication Layers. 4. IANA Protocol Numbers: http://www.iana.org/assignments/protocol-numbers 42