TCS Network Engineer Interview Questions, Process, and Tips for Experienced

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

• OSPF has four states: Down, Init, 2-Way, Exstart, Exchange, Loading, and Full.

• During the Down state, the router does not have any information about its neighbors.

• In the Init state, the router sends Hello packets to discover neighbors.

• The 2-Way state is when bidirectional communication is established bet...read more

SD-WAN architecture is a software-defined approach to managing wide area networks.

• SD-WAN uses software to control the connectivity, management, and services between data centers and remote branches.

• It allows for centralized control and automation of network traffic.

• SD-WAN can prioritize critical applications and optimize bandwidth usage.

• Examples of SD-WAN vendors include Cisco, VMware, and Silver Peak.

STP selection process determines the root bridge and designated ports in a network.

• STP selection process starts by electing a root bridge based on the lowest bridge ID.

• Each switch then determines the best path to the root bridge.

• Designated ports are selected on each segment based on the lowest path cost to the root bridge.

• Non-designated ports are put in blocking state to prevent loops in the network.

OSPF LSA types include Router LSA, Network LSA, Summary LSA, and ASBR Summary LSA, each serving different purposes in OSPF routing.

• Router LSA: Describes the router's directly connected links.

• Network LSA: Represents multi-access networks and lists all routers connected to the network.

• Summary LSA: Summarizes routes from one area to another.

• ASBR Summary LSA: Summarizes external routes injected into OSPF by an ASBR.

• LSA typ...read more

BGP states refer to the different stages a BGP session goes through during establishment and maintenance.

• Idle state: Initial state when BGP process starts

• Connect state: Attempting to establish a TCP connection

• OpenSent state: Sending an OPEN message to peer

• OpenConfirm state: Waiting for an OPEN message from peer

• Established state: BGP peers are fully synchronized and exchanging routing information

Data link layer is responsible for node-to-node communication, while network layer is responsible for end-to-end communication.

• Data link layer operates at Layer 2 of the OSI model and is responsible for framing, error detection, and flow control.

• Network layer operates at Layer 3 of the OSI model and is responsible for logical addressing, routing, and path determination.

• Examples of data link layer protocols include Ethe...read more

Firewall filters traffic based on security rules, while router forwards data packets between networks.

• Firewall is used to block or allow traffic based on security rules, while router is used to forward data packets between networks

• Firewall operates at the network layer (Layer 3) or above, while router operates at the network layer (Layer 3)

• Firewall can inspect and filter traffic based on IP addresses, ports, protocols,...read more