Switching Interview Questions For CCNA and CCNP Engineers

After IGP, BGP and MPLS interview question, Now I am adding switching basic questions. Please read the below questions:-

1. Difference between hub, bridge and switch?
2. What is mac address and why it is required?
3. In layer 2 domain do we need ip address for communication?
4. What is arp and why it is required?
5. What is Spanning Tree Protocol aka STP?
6. What is the difference between STP, MSTP, PVST and RSTP?
7. Can we use the two same paths for same vlan?
8. What is the difference between broadcast and collision domain?
9. Define type of lan traffic.
10. What is destination address of broadcast frame?
11. Can we connect a switch to switch with straight cable?
12. Define functions of switch.
13. What is arp timeout?
14. What is aging process?
15. What is BPDU?
16. What is path cost?
17. Define selection criteria of STP root bridge.
18. How to non bridge decide which port will elect as root port?
19. If a nonroot bridge has two redundant ports with the same root path cost, how does the bridge choose which port will be the root port?
20. Port states of spanning tree protocol.
21. If the users face delay during initial login, what you will suggest to implement?
22. Why spanning tree BPDU filter is used?
23. Can I use BPDU filter on trunk ports?
24. What is port security?
25. I want to learn only a single mac from the port, what need to be configured?
26. Can we use spanning port-fast on trunk ports?
27. If management ip address is changed, will user’s traffic will be dropped?
28. Difference between trunk and access port?
29. What is UDLD and why it is required?
30. What is interface vlan on switch?
31. How to perform inter vlan routing without layer 3 device?
32. How to stop superior bpdu participating in switching domain?
33. How Vlan In Local Switching Domain is selected?
34. How to provide redundancy to MPLSVPN customer?
35. What are deep buffers in switching?
36. How to build Low Latency Data Center Switching Fabric?


Click Here To Read Rest Of The Post...

MPLS Interview Questions for CCNA and CCNP Engineers

After IGP and BGP questions, I prepared basic list of MPLS interview questions which could help you to clear your next level. In the up coming post, I will be covering switching. Below is the list of questions:-

1. What is the difference between VPN and MPLS?
2. What is MPLS and why it is being so popular in short time?
3. What is the protocol used by MPLS?
4. MPLS works on which layer?
5. What is the difference between P and PE router?
6. Can I make my PE router as P?
7. Two routers are having 4 equal cost links, how many ldp sessions will be established?
8. My LDP router id, OSPF router id and BGP router id is different, will it work to forward the traffic of customers or not?
9. What is Penultimate Hop Popping and why it is required? Which router performs the PHP function?
10. I am receiving aggregate label, what does it mean?
11. What are the different types of labels?
12. How to make customer route unique?
13. What is the difference between RD and RT?
14. Can I assign a same RD to two different customers?
15. Is RD travels in route update?
16. My customer is having three branches and all are attached to three different PEs, In this case can I use the different vrf names?
17. What is downstream on demand?
18. How to filter MPLS labels?
19. What is the default range of MPLS labels in Cisco routers? How to extend that range?
20. Without route reflector can I implement MPLS?
21. What is the difference between VPNv4 and IPv4 address family?
22. What is MP-iBGP? Can we use normal BGP in lieu of MP-iBGP?
23. What is LIB, LFIB?
24. What is CEF and without enabling CEF, can we make MPLS work?
25. I am receiving end to end customer routes on various PE but not able to ping those routes, what’s could be the problem?
26. What is explicit null and implicit null?
27. Default timers of LDP?
28. Does LDP require OSPF, IS-IS or BGP?
29. In neighbor discovery command, I am receiving only xmit, what does it mean?
30. What is transport address?
31. What is the RFC of MPLS?
32. Why MPLS is called multi protocol?
33. What is the difference between MPLS, SSL and IPSec?
34. I am using different vendor products and want to implement TDP, what type of challenges will you face?
35. Does MPLS support IPv6?
36. Can I use the existing IPv4 MPLS backbone for IPv6?
37. Define various troubleshooting commands in MPLS?
38. What is forward equivalence class aka FEC?
39. What is adjacency table?
40. Difference between MPLS IP and MPLS Label Protocol LDP command?
41. If MPLS get disable, will it harm my IGP or IPv4 traffic?
Click here for answers
42. What is MPLS-TP?
43. What is downstream and upstream router in MPLS? 44. Difference between MPLS and MPLS-TP?
45. How Does LDP Initializes?
46. What is Cell Mode MPLS Over ATM?
47. Difference Between VC Based Multiplexing And Logical Link Control Encapsulation in ATM?
48. Basics of ATM?
49. ATM is packet or circuit switching?
50. Is LDP Required for VPNv4 Labels?
51. What will happen if you see your PE loopback in vpnv4 table?
52. What is Bidirectional Forwarding Detection?
53. Different types of PseudoWire?
54. Modes of EoMPLS (Ethernet over MPLS)
55. What is L2VPN Over Metro Ethernet?
56. What is E-VPN(Ethernet VPN)?
57. what is FEC in traditional IP routing and MPLS?
58. How does CEF understand overlapping of ip addresses ?
59. What is the difference between Optimum, Fast and CEF Switching?
60. Advantages of MPLS.
61. Define CEF FIB table entries.


Click Here To Read Rest Of The Post...

Upgrade IOS:TCP Packet Denial of Service Vulnerability

Cisco has raised a alarm about denial of services vulnerability that may allow remote unauthenticated attacker to cause an affected device to reload. Only IOS XR and IOS XE are not affected. According to Cisco no other products are currently known to be affected. So a best is to save your downtime by fixing the issues with the help of patches. Being its friendly nature make CISCO more popular. See the list given below:-

Vulnerable devices are running an affected version of Cisco IOS Software, and are configured for any of the following:
1. A specific TCP window size
2. TCP path MTU discovery (PMTUD)
3. Stateful Network Address Translation (SNAT) with TCP as the transport protocol
For detailed information refer this link.



Click Here To Read Rest Of The Post...