10+ Network Engineer L1 Interview Questions and Answers for Freshers

Network protocols and port numbers are essential for communication between devices on a network.

• TCP/IP is the most commonly used protocol suite

• HTTP uses port 80, HTTPS uses port 443

• SMTP uses port 25, POP3 uses port 110, IMAP uses port 143

• FTP uses port 21, SFTP uses port 22

• DNS uses port 53

• SSH uses port 22

• Telnet uses port 23

STP is a network protocol that prevents loops in Ethernet networks. VLANs divide a network into separate broadcast domains. DHCP assigns IP addresses, DNS resolves domain names. OSI model defines networking functions in layers.

• STP (Spanning Tree Protocol) prevents loops by blocking redundant paths in a network.

• VLAN (Virtual Local Area Network) divides a network into separate broadcast domains to improve network performance and security.

• DHCP (Dynamic Host Configuration Protoco...read more

DWDM stands for Dense Wavelength Division Multiplexing, OSPF is Open Shortest Path First, EIGRP is Enhanced Interior Gateway Routing Protocol, OLT is Optical Line Terminal, and ONU is Optical Network Unit.

• DWDM is a technology that multiplexes multiple optical carrier signals on a single optical fiber by using different wavelengths of laser light.

• OSPF is a routing protocol used for exchanging routing information between routers in an IP network.

• EIGRP is a Cisco proprietary rou...read more

Routing involves forwarding data packets between networks, while switching involves forwarding data packets within a network.

• Routing is the process of determining the best path for data packets to travel from source to destination across different networks.

• Switching is the process of forwarding data packets within a network based on MAC addresses.

• OSPF (Open Shortest Path First) is a routing protocol used to find the best path for data packets in IP networks.

• BGP (Border Gatewa...read more

Yes, CCNA certified. EtherChannel is a technology used to combine multiple physical links into a single logical link for increased bandwidth and redundancy.

• EtherChannel is a Cisco proprietary technology used to bundle multiple physical links into a single logical link.

• It provides increased bandwidth and redundancy by load balancing traffic across the links.

• EtherChannel can be configured in different modes such as on, auto, desirable, or passive.

• It is commonly used in network ...read more

A VLAN (Virtual Local Area Network) is a logical grouping of devices on the same physical network, allowing for segmentation and improved network performance.

• VLANs are used to separate broadcast domains in a network.

• They can improve network security by isolating traffic between different VLANs.

• VLANs can be configured based on port, MAC address, or protocol.

• Example: VLAN 10 for finance department, VLAN 20 for marketing department.

BGP stands for Border Gateway Protocol, a routing protocol used to exchange routing information between different autonomous systems on the internet.

• BGP is used to make routing decisions based on network policies, rules, and paths.

• It is a path vector protocol that allows routers to share information about the best path to reach a certain destination.

• BGP operates on TCP port 179 and uses TCP connections to exchange routing information.

• BGP is classified into two types: eBGP (Ex...read more

DHCP is a network protocol that assigns IP addresses to devices on a network, while DNS translates domain names to IP addresses.

• DHCP stands for Dynamic Host Configuration Protocol

• DHCP assigns IP addresses to devices on a network dynamically

• DNS stands for Domain Name System

• DNS translates domain names to IP addresses

• DHCP helps in automatic IP address configuration

• DNS helps in resolving domain names to IP addresses

Subnet mask is a 32-bit number used to divide an IP address into network and host portions.

• Subnet mask determines which part of an IP address is the network portion and which part is the host portion.

• It is represented in decimal format (e.g. 255.255.255.0) or CIDR notation (e.g. /24).

• Common subnet masks include 255.0.0.0, 255.255.0.0, and 255.255.255.0.

A network is a group of interconnected devices that communicate with each other to share resources and information.

• A network can be wired or wireless.

• Devices on a network can include computers, printers, routers, and servers.

• Networks can be local (LAN) or wide area (WAN).

• The internet is a global network of networks.

• Networks use protocols such as TCP/IP to ensure reliable communication.

• Security measures such as firewalls and encryption are used to protect networks from unautho...read more