Network Trouble shooting

Question 1

What tools can you use to troubleshoot latency

Answer 1

• Ping
• Traceroute
• MTR
• hping
• tcpdump
• Microsoft Network Monitor (Protocal Analyzer)
• SNMP (Simple Network Management Protocol)
• Protocol analyzers (Like wireshark)

Question 2

How can ping be used to troubleshoot latency issues?

Answer 2

It can verify the reachability of devices on a network, and provide data on how long it took an ICMP packet to reach its destination and back.

Question 3

How can Traceroute be used to troubleshoot latency issues?

Answer 3

Traceroute provides response times on a hop-by-hop basis, so you end up with a list of all the devices between the source and destination and how responsive those hops are at that point in time.

Question 4

How does Traceroute work?

Answer 4

The traceroute utility works by sending a UDP (for Linux-based systems) or ICMP (for Windows systems) with a TTL value of 1.

Once the packet reaches the first hop down the path to the destination, that device realizes the TTL limit is reached and responds back to the source device, which collects the round-trip time value. The next packet will then be set to a TTL of 2, then 3 and so-on until the final destination IP is reached.

Question 5

What does SNMP mean

Answer 5

Simple Network Management Protocal.

Question 6

How can Protocol analyzers be used to troubleshoot latency?

Answer 6

A protocol analyzer such as Wireshark can perform deep-packet inspection to determine exactly which packets are slow, where they are going and what they are doing.

If a user is complaining about an application being slow, that application may be distributed across multiple servers. The protocol analyzer can determine whether the problem is limited to a specific part of the overall distributed architecture.

Question 7

List the OSI Model in order

Answer 7

• Layer 1: Physical Layer
• Layer 2: Data Link Layer
• Layer 3: Network Layer
• Layer 4: Transport Layer
• Layer 5: Session Layer
• Layer 6: Presentation Layer
• Layer 7: Application Layer

Question 9

____ is a computer program which combines the functions of the traceroute and ping programs in one network diagnostic tool

Answer 9

MTR

Question 10

How does tcpdump help with troubleshooting network latency issue’s?

Answer 10

It can help with diagnosing packet loss/latency issues by performing packet captures. Doing so can help isolate the issue at the networking and application layers.

Question 11

Latency can either be measured as the ___________ or ___________

Answer 11

Round Trip Time (RTT) or the Time to First Byte (TTFB):

Question 12

What would you be looking

Answer 12

A protocol analyzer such as Wireshark can perform deep-packet inspection to try and determine exactly which packets are slow, where they are going and what they are doing.

Question 13

If a user is complaining about an application being slow, that application may be distributed across multiple servers in a distributed architecture. A _______________ can determine whether the problem is limited to a specific part of the overall distributed architecture.

Answer 13

protocol analyzer

Question 14

Increasing TCP window size can be used to improve what?

(TCP Window Scaling)

Answer 14

Data troughput or speed.

Question 15

____ is defined as the amount of time it takes a packet to get from the client to the server and back.

Answer 15

RTT

Question 16

_____ is the amount of time it takes for the server to receive the first byte of data when the client sends a request.

Answer 16

TTFB

Question 17

___________ can also help reduce latency across your network as you can group together endpoints that communicate most frequently with each other.

Answer 17

Subnetting

Question 18

You can use a _____________ to help offload traffic to parts of the network with the capacity to handle some additional activity.

Answer 18

load balancer