Mitigating Connectivity Issues in Interconnected Data Centers
Question
Network designers plan to interconnect two geographically separated data centers using an Ethernet-over-MPLS pseudowire.
Within that design, the link between the sites is stable, there are no apparent loops in the topology, and the root bridges for the respective VLANs are stable and unchanging.
What additional aspect of the design should be adjusted to mitigate the chance of connectivity issues to the peer data center when the connection takes place?
Answers
Explanations
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A. B. C. D.B.
The plan to interconnect two geographically separated data centers using Ethernet-over-MPLS pseudowire requires careful consideration of the network design to mitigate any potential connectivity issues. Based on the given information, the link between the sites is stable, there are no apparent loops in the topology, and the root bridges for the respective VLANs are stable and unchanging. However, there is an additional aspect of the design that needs to be adjusted to ensure the smooth functioning of the network.
Option A: Enable 802.1d on one data center, and 802.1w on the other. This option is not recommended as it involves using different versions of Spanning Tree Protocol (STP) in the two data centers. This can lead to inconsistencies and potential issues in the network. It is not a viable solution to mitigate connectivity issues.
Option B: Ensure that the spanning tree diameter for one or more VLANs is not too large. The spanning tree diameter is the maximum number of switches that can be present in a loop-free topology. A larger diameter can result in longer convergence times and network instability. Thus, this option is a valid recommendation to ensure that the spanning tree diameter is not too large, which helps to mitigate connectivity issues.
Option C: Enable UDLD on the link between the data centers. UniDirectional Link Detection (UDLD) is a feature that can detect and prevent unidirectional links in the network. It is useful when a link is physically functional but carries traffic in one direction only. This option is not relevant to the given scenario as there is no indication of a unidirectional link.
Option D: Enable root guard on the link between the data centers. Root guard is a feature that protects against the introduction of unauthorized switches into the network. It blocks any port that receives BPDUs (Bridge Protocol Data Units) from switches that are not designated as the root bridge for the respective VLAN. This option is also a valid recommendation to prevent any unauthorized switches from introducing instability into the network.
In conclusion, options B and D are the most relevant recommendations for mitigating connectivity issues in the given scenario. While UDLD and the use of different versions of STP may have their uses in other situations, they are not applicable in this case.
