💡
Network Fundamentals
  • About This Site
  • Network
  • Medium
  • Types of Network:
  • LAN
  • MAN
  • WAN
  • Internet
  • Types of Internet Connections
  • Cable Connection
  • DSL Connection
  • Internet Standard & Protocols
  • Internet Networking Model
  • SNA Networking Model
  • OSI Networking Model
  • TCP-IP Networking Model
  • TCP-IP Layers
  • Application Layer
  • HTTP (Hyper Text Transfer Protocol)
  • Transport Layer
  • TCP (Transmission Control Protocol)
  • Network Layer
  • IP (Internet Protocol)
  • IPv4:
  • IPv4 Address parts
  • IPv4 Address Classes
  • IPv6:
  • Data-Link Layer
  • Physical Layer
  • An Ethernet
  • A SOHO LAN Network
  • An Enterprise LAN Network
  • Physical Layer Standards
  • Data-Link Layer Standards
  • Transmitting Data over Ethernet UTP
  • Transmitting Data over Fiber Optic Cable (using Hot-Pluggable Transceivers)
  • Cabling Pinouts (Ethernet UTP)
  • Cabling Pinouts (Fiber Optic)
  • Ethernet Standards (UTP)
  • Ethernet Standards (Fiber Optic)
  • LAN Data-Link Layer Protocols
  • Ethernet Addressing (MAC)
  • Types of Networking Devices
  • HUB
  • SWITCH
  • CSMA/CD (Carrier Sense Multiple Access / Collision Detection):
  • Lease-Line WAN
  • WAN Data-Link Layer Protocols
  • HDLC Encapsulating and Re-encapsulating
  • Ethernet WAN (EoMPLS)
  • IP Routing (BIG FLOW)
  • Router
  • Subnetting
  • Binary Rules
  • Binary Method Example 1
  • Binary Method Example 2
  • Binary Method Example 3
  • Subnetting Quick Method Rules
  • Subnetting Quick Method Example 1
  • Subnetting BEST Method Rules
  • Subnetting BEST Method Example 1
  • Subnetting BEST Method Example 2
  • Subnetting BEST Method Example 3a
  • Subnetting BEST Method Example 3b
  • Subnetting BEST Method Example 3c
  • Subnetting BEST Method Example 4
  • Dynamic Routing Protocol
  • DNS (Domain Name System)
  • ARP (Address Resolution Protocol)
  • PING (Packet Internet Groper)
  • Cisco OS (IOS)
  • Memory Types
  • Cisco CLI
  • Console Port:
  • Telnet Access (Teletype network) (P No. 23):
  • SSH (Secure Shell) (P No. 22)
  • Console Cabling
  • CLI Modes
  • Securing User Mode and Privileged Mode
  • Securing User & Privileged Mode For Console Users
  • Securing User & Privileged Mode For Telnet Users
  • Securing User & Privileged Mode For SSH Users
  • AAA (Authentication, Authorization and Accounting) Server
  • AAA 802.1x Protocols(Radius & TACACS+)
  • Ethernet LAN Switching
  • VLAN
  • Configuring VLAN
  • VTP (Vlan Trunking Protocol)
  • Trunk Port
  • Trunking Protocol (802.1Q)
  • DTP (Dynamic Trunking Protocol)
  • Voice VLAN
  • Why STP?
  • What STP Does?
  • How STP works?
  • STP Messages (BPDU)
  • Electing a RB (Root Bridge/Switch)
  • Electing One Root Port (on each Non RB)
  • Elect One/Multiple Designated Ports on each Non RB:
  • Changing the STP Settings:
  • STP (Spanning Tree Protocol)
  • STP Convergence (if something changes/link fails):
  • STP (Spanning Tree Protocol) Versions
  • STP/RSTP States:
  • PortFast
  • BPDU Guard
  • RSTP (Rapid Spanning Tree)
  • Port Roles in RSTP
  • RSTP Port States
  • Ether Channel
  • Switched Virtual Interface
  • Half Duplex
  • Full Duplex
  • Autonegotiation
  • Duplex Mismatch:
  • Verifying Duplex Mismatch
  • Number History
  • 10 to the power of x
  • 2 to the power of x
Powered by GitBook
On this page

SWITCH

PreviousHUBNextCSMA/CD (Carrier Sense Multiple Access / Collision Detection):

Last updated 4 years ago

  • The Switch is a L2 because it uses Data-Link Layer standards. Meaning Switch refers to MAC Addresses (which is a Layer 2 Address) & MAC Table (which is a Layer 2 Table)

  • When a Switch receives a Frame on its port it refers to the Frame (Header&Trailer) & forwards the Frame to the relevant Port only (forward-versus-filter decision) and not to all other ports (not to filter). (Mentioned in )

  • The Switch supports Half-Duplex as well as Full-Duplex logic.

  • To Avoid/Detect Collisions Switch uses CSMA/CA & CSMA/CD algorithms.

  • The Neighbor device connected to a HUB must always set it's Duplex settings to Half-Duplex. Hence if a Switch is connected to a HUB it must always set its port connected to that HUB to a Half-Duplex setting.

  • To perform LAN Switching, Switch performs these 3 actions:

    1. Examine the SMAC & make the entry in the MAC Table

    2. Deciding when to forward or not to forward depending on the DMAC Address

    3. To forward only one copy of the frame to avoid creating a loop Using STP logic.

  • The Switch is an intelligent device.

    2) As soon as a switch receives a frame on its port it will read MAC Address refer MAC Table & take the forwarding decision.

    3) MAC Address is a L2 Address, MAC Table is a L2 Table, Hence Switch is a L2 Device.

    4) On receiving a Frame on its port switch will open L2 information, Read DMAC Address, refer MAC Table & forward the frame to the relevant port only & not to all other ports. Whereas HUB will forward it to all other ports.

    5) Switch segments the Network whereas HUB extends the Network.

    6) Because Switch refers to the MAC Table hence MAC Table should be populated with MAC Addresses.

    7) MAC Table can be populated in 2 ways:

    i) Administrator can make a Static MAC entry in the MAC table.

    ii) Switch does self-learning of MAC entry in MAC Table when a Frame traverses a Switch.

    8) Huge MAC Table has 3 issues: High Memory utilization, High CPU utilization & Frame forwarding delay.

    9) To overcome these issues cisco defined 4096 MAC entries (old times) in the MAC Table anything (newer Switches like Cisco 2960-XR have bigger CAM (Physical Space) hence can store 7299/8000 entries). And any MAC entry in MAC Table that is not sending Frame in 5 mins will be considered as Stale & will be removed from the MAC Table.

  • Router/Switch contains 4 different .

Reference:

  • CCNA 200-301 OCG, Volume 1, Pg. 55-56 - Wendell Odom.

  • RST Notes

Networking device
detail
Types of Memory