Bridging the Gap – Networking Foundations for Cloud and Devops

Youtube Session

Introduction

• Networking basics for IT, cloud, and DevOps.

Network Basics

• Enables communication by connecting systems via physical components (modems, cables, switches)
• Evolved from ARPANET to global internet using routers and protocols (TCP/IP, HTTP).
• Enables:
  • Easy communication
  • Centralized management
  • File, information, and data sharing
  • Resource and storage sharing
  • Collaboration
• Types of Networks:
  • PAN (Personal Area Network) : Smallest; for individual’s devices; connects personal devices for communication/data sharing.
  • LAN (Local Area Network) : Covers small areas (homes/offices); enables high-speed local communication.
  • CAN (Campus Area Network) : Between LAN and MAN; covers limited areas like university campuses, military bases, or corporate parks.
  • MAN (Metropolitan Area Network) : Larger than LAN, smaller than WAN; covers a city or campus.
  • WAN (Wide Area Network) : Spans large areas; uses leased telecom lines; Internet is a global WAN.

Types of Network Topologies

• • Bus Topology : All devices share a single line; simple but prone to collisions.
  • Star Topology : Devices connect to the central hub; easy to manage and isolate failures.
  • Ring & Mesh Topologies : Ring passes data in loops; Mesh connects all nodes directly for redundancy.
  • Most Used : Star Topology; often hybrid (e.g., Star + Bus) in practice.

Internet Protocol Address (IP)

•  Unique numerical label for devices on IP networks.
• Versions :
  • IPv4: 32-bit; dotted-decimal (e.g., 172.16.254.1); divided into 4 bytes; classes A-E; nearly exhausted.
    • Classes: A (Network ID: Byte 1, Host ID: Bytes 2-4), B (Bytes 1-2 Network, Bytes 3-4 Host), C (Bytes 1-3 Network, Byte 4 Host).
    • Class D: Multicast; Class E: Experimental.
  • IPv6 : 128-bit; hexadecimal with colons (e.g., 2001:0DC8:EC04:0001:0000:0000:0000:F00A); developed for address exhaustion; more efficient; backward compatible via NAT64/6to4.
• Class Ranges (IPv4):
  
• Private Ranges (IPv4) :
  • Class A: 10.0.0.0–10.255.255.255
  • Class B : 172.16.0.0–172.31.255.255
  • Class C: 192.168.0.0–192.168.255.255.
• APIPA : 169.254.0.0–169.254.255.255; local only; no default gateway.
• Loopback : 127.0.0.0–127.255.255.255 (commonly 127.0.0.1); for testing; local only; no default gateway.
• Public vs Private IPs :
  • Public : Globally unique, routable; assigned by IANA/RIR; e.g., 82.129.80.111 (find via “What is my IP?”).
  • Private : Not routable on internet; local assignment; translated for internet access; e.g., 192.168.1.1

Subnetting

• Divides a network into smaller subnets for performance, security, organization.
• Process : Borrow bits from host portion; subnet mask determines bits borrowed and subnet size.
• CIDR (Classless Interdomain Routing) : Shorthand for IP + mask (e.g., /24); flexible; efficient routing; replaces class system.
  • Key: Flexible subnetting (e.g., /29 = 8 IPs); groups ranges; efficient for ISPs.
• VLSM (Variable Length Subnet Mask) : Subnets of different sizes/masks; improves IP use/flexibility.
  • Examples: 9.9.0.0/24 (256 addresses), 9.9.96.0/29 (6 addresses), etc.
• Supernetting : Combines smaller networks into larger block (route aggregation).
  • Benefits: Reduces routes; simpler ISP ads; better performance.
  • Example: 192.168.0.0/24 to 192.168.3.0/24 → 192.168.0.0/22.
• FLSM (Fixed Length Subnet Mask) : All subnets same size/mask; traditional.
  • Example: 192.168.0.0/24 with /26 → Four 64-IP subnets (192.168.0.0/26, etc.).

DHCP (Dynamic Host Configuration Protocol)

• Dynamically assigns IPs/configurations; simplifies management.
• Process (DORA) : Discover → Offer → Request → Acknowledge (4-step handshake).
• Benefits : No manual IPs; avoids conflicts; easy scaling; flexible (IPs reused).

Switches and Routers

• Switches :
  • Direct data to intended recipients; improve security/efficiency.
  • Switching: Forwards packets within a network.
  • Example: Data from one node sent only to destination via switch.
• Routers :
  • Connect networks; route data; manage IP traffic between subnets.
  • Routing: Selects best path for traffic.
  • Example: Finds optimal path from sender to receiver PC, avoiding congestion.
• Types of Routing :
  • Static : Manual config by admins.
  • Dynamic : Auto-learn via protocols; routers exchange info.
  • Default : Forwards unknown packets to gateway of last resort.
• Routing Protocols :
  • IGP (Interior) : RIP, EIGRP, OSPF, IS-IS.
  • EGP (Exterior) : BGP.
  • Routing Table : Network topology info; determines best path.

DNS (Domain Name System)

• Hierarchical system translating domains (e.g., example.com) to IPs (e.g., 192.0.2.1).
• Lookup Process (Steps) :
  • User queries “example.com” (IP: 8.192.0.16).
  • Sent to Recursive Resolver.
  • Resolver queries Root Server.
  • Root directs to .com TLD Server.
  • TLD provides Authoritative Server names.
  • Resolver queries Authoritative Server.
  • Returns IP to user.
• Domain Structure :
  • Subdomain: e.g., “www” in www.example.com.
  • Second-Level Domain: e.g., “example”.
  • Top-Level Domain: e.g., “.com”.
• Web Address Anatomy : e.g., https://blog.hubspot.com/website/what-is-a-domain (Protocol: https://; SLD: hubspot; Subdirectory: website; Path: what-is-a-domain).
• Record Types :
  • A/AAAA: Domain to IPv4/IPv6.
  • CNAME: Alias one domain to another.
  • MX/TXT/Others: Mail servers (MX); text data (TXT); NS, PTR, SOA, SRV for advanced.

Server-Client Architecture

• Client (e.g., PC/smartphone) requests; server processes/response the request (may access database).
• Example: Client requests emails; server searches and delivers.

Basic Networking Commands

• ping : Tests reachability (ICMP Echo).
• tracert/traceroute : Shows path to destination.
• ipconfig/ifconfig : Displays IP, mask, gateway.
• nslookup : DNS queries.
• netstat : Active connections/stats.
• arp : IP-to-MAC mappings.
• route : View/modify routing tables.
• telnet : Remote connection (use SSH instead).

Conclusion

• Key Takeaways :
  • Networking/DNS enable seamless cloud/DevOps
  • understand lookup, structures, architecture, commands for efficient, reliable systems.
• Future Relevance :
  • Fundamentals bridge traditional networking to cloud demands.