A network administrator is troubleshooting a connectivity performance issue. As part of the troubleshooting process, the administrator performs a traceout from the client to the server, and also from the server to the client. While comparing the outputs, the administrator notes they show different hops between the hosts.
Which of the following BEST explains these findings?
Correct Answer: A
Asymmetric routing is a situation in which the path taken by data packets between two points in a network is different in both directions. It can be caused by factors such as unequal cost paths, policy-based routing, load balancing, or network topology changes1 In this scenario, the network administrator is troubleshooting a connectivity performance issue, which could be affected by asymmetric routing. For example, if one path has more congestion, latency, or packet loss than the other, the performance of the communication between the client and the server will be degraded2 To diagnose the issue, the network administrator performs a traceout from the client to the server, and also from the server to the client. A traceout is a tool that shows the route and the number of hops that a packet takes to reach a destination. By comparing the outputs, the network administrator can identify if there is asymmetric routing in the network3 If the outputs show different hops between the hosts, it means that the packets are taking different paths in each direction, which is a sign of asymmetric routing. Therefore, the best answer is A. Asymmetric routing.
The other options are not as likely to explain the findings. A routing loop is a confusion about the reachability of a destination network, which causes packets to loop endlessly between two or more routers4 A switch loop is a situation in which there is more than one layer 2 path between two endpoints, which causes broadcast storms and MAC database instability5 An incorrect gateway is a configuration error that prevents a device from reaching the intended destination network6 None of these options would necessarily result in different hops between the hosts, as they would either cause the packets to be dropped, discarded, or delayed, but not rerouted. Therefore, the best answer is A.
Asymmetric routing.
References:
https://en.wikipedia.org/wiki/Routing_loop
https://www.networkstraining.com/what-is-asymmetric-routing/
https://learn.microsoft.com/en-us/troubleshoot/windows-server/networking/ip-default-gateway-settings-assigned
https://superuser.com/questions/1715808/cant-access-router-settings-default-gateway-not-working-as-expected