Q: 12
[InfiniBand Configuration]
Why is the InfiniBand LRH called a local header?
Options
Discussion
Option A, but if the question had said "local link" instead of "local subnet," C would be right. In InfiniBand, LRH handles traffic within the whole local subnet, not just the wire. Seen these details trip people up in practice.
Ugh, these vendor questions are always too vague. Probably C since "local" sounds like just the link to me here.
Option A here. LRH deals with routing inside the local subnet, not just a single physical link. Pretty sure about this from official docs, but I could be missing some corner case if "local" got redefined somewhere else.
Have seen similar in practice exams and official docs, A is right since LRH routes within the local subnet.
D , but similar exam reports usually pick A for subnet-level routing not just link-level.
Why wouldn't it be C? The LRH is about routing within the subnet, so A sounds better than just local link access.
A tbh, LRH routes traffic just inside the local subnet.
Totally agree with A. The LRH is about routing within the local subnet, not just a single point-to-point InfiniBand link. Local here really means intra-subnet traffic. Someone let me know if I'm missing a recent update.
Probably A. Similar questions mention LRH for routing between nodes in the local subnet only, not just a point-to-point link.
I don’t think C is right. "Local" in LRH refers to the entire subnet, not just a single link. A fits because it’s about routing traffic between nodes inside the local subnet. Pretty sure this matches both exam wording and InfiniBand docs, but open to correction if there’s an angle I missed. B might trip people up since LIDs come from the subnet manager, but that’s not what makes it a local header.
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