Sunday, June 14, 2020

Interview Questions - Networking (Cisco/Juniper/Citrix , etc)

QoS Questions
=============
1. Shaper vs Policer
2. Usecase SrTCM vs TrTCM
3. Algorithmic explanation of SrTCM vs TrTCM
4. How WRED works ?
5. Color aware WRED and Precedence management ?
6. DWRR vs WRR ? 
7. How to load share among queues using Weights and different QoS Algorithms ?
8. Why do you need "trust COS" port-level configuration? is it going to prevent all the attacks ? 

ASIC and Network Questions:
======================
1. broadcom XGS pipeline
2. How L2 gets forwarded.
3. On Ethernet header what decides the next protocol ? If ethertype is used for something else too, what is it for ?
4. Can you draw a frame and it's fields and their significants for: Ethernet+double-tag VLAN + IPv4 header

Operating Systems:
===============
1. Mutex Vs Semaphore
2. IPC mechanisms : Signal Handling Basics, Socket Programming (NETLINK vs RAW SOCKET), 
3.Thread safe programming
4. Memory Layout of Process vs Thread. 


Design Questions:
==============
1. What Datastructure will you use for MAC table and IP routing table ? explain in detail about your decisions. 
2. How do you breakdown a problem: say for example if the current scenario of Covid-19 lockdown needs to be relaxed slowly over the weeks. how do you do it ? 
3. What is the difficult problem that you have faced recently and how did you solve it and talk about it .

C Programs:
==========
1. Endianness of the system
2. HTONS and NTOHS function
3. Height of a Binary tree
4. Reverse a linked list


Few Must DOs:

Monday, May 18, 2020

Data Structures and Algorithms

Big O notation:
- Worst case execution complexity
O(1) : access the data at first lookup
O(n) : lookup a data in a list of n items (linear complexity).
O(n^2): nested loops(2loops)
O(n!) : loop for each item in the list of data

- Space complexity

Good code:
- Readable
- Scalable (speed and Memory)

For Quick Overview : https://drive.google.com/drive/folders/1t75vJEgzndUVp_Jndh9O7tPN9xTu5s57?usp=sharing

For Distributed design : http://book.mixu.net/distsys/intro.html