CCNA
Cisco Certified Network Associate certification resources
HDLC Encapsulation Protocol
HDLC is the default encapsulation protocol on point-to-point connections, dedicated links, and circuit-switched links when both ends of the link are Cisco devices. It is a synchronous Data Link layer bit-oriented protocol, originally developed from IBM’s Synchronous Data Link Control (SDLC), and later standardized by ISO as ISO/IEC 13239. HDLC provides both connection-oriented and connectionless...
WAN Encapsulation Protocols
The network layer passes the data to the data link layer for transmission over the physical layer. The Data Link layer creates frames by adding the necessary checks and controls around the Network layer data. The encapsulation on a router serial interface must be configured to guarantee the correct encapsulation method is used. Different WAN...
Serial Cable: Types, Pinouts, and DTE/DCE Connections
A serial cable is used to interconnect DTEs (Data Terminal Equipment) and DCEs (Data Communications Equipment). DTEs are the devices that actually generate or receive the data being communicated, such as a computer, router, or terminal. DCEs are the devices that facilitate and relay that data across the connection, such as a modem or CSU/DSU....
Statistical Time-Division Multiplexing (STDM): Complete Guide
Statistical Time-Division Multiplexing is an advanced multiplexing technique that dynamically allocates transmission time slots to active channels, eliminating the bandwidth waste inherent in standard Time-Division Multiplexing (TDM). Understanding STDM — how it differs from TDM and FDM, how its frame structure works, and where it is applied in real WAN protocols — is essential knowledge...
Time Division Multiplexing (TDM): Complete Guide
Multiplexing is a technique that allows multiple logical signals to share a single physical channel. The two most fundamental multiplexing techniques in telecommunications and networking are Time Division Multiplexing (TDM) and its dynamic counterpart, Statistical Time Division Multiplexing (STDM). This guide focuses on TDM, its frame structure, real-world implementations in T1 and E1 circuits, Cisco...
Point to Point Communication Links
Usually, a point to Point links is used when permanent dedicated connections are required. It is a pre-established WAN communications path connection, which can securely connect two or more locations for private data services. The point to point links is available with different standards and different speed including T1 lines, Ethernet or DS3. Enterpriser usually...
Serial Communication – Complete Guide
Serial communication is the famous and broadly used technique to transfer data between processing equipment and peripherals. Serial communication is used to transfer data across the WANs. The sending router encapsulates the data using a communication protocol. The encapsulated data is sent on a physical medium to the WAN, and the receiving router de-encapsulates the...
Parallel port
Parallel ports usually used for connecting printers, computers, and other devices that required high bandwidth. The port is also used for interconnection between interior components of the devices. Parallel ports can be transmitted simultaneously over multiple wires. Theoretically parallel port is eight-time faster than a serial port. The serial port sends one bit while at...
Serial Port: How Serial Interfaces Work in Networking
A serial port allows a PC or network device to transmit or receive data one bit at a time over a single channel. Serial interfaces are the foundation of point-to-point WAN connections — the leased line links that connect remote sites across cities and countries. While USB has replaced serial ports on most PCs, serial...
VPN Technology
VPN is the abbreviation for a virtual private network. VPN technology creates a safe and encrypted connection over an unsecured network, such as the Internet. It extends a private network using a public network, such as the Internet. A virtual private network uses virtual connections known as VPN tunnels instead of a dedicated Layer 2...