What must happen when adaptive routing delivers packets out of order?
Why C is the answer
The receiving side must place them correctly
NICs must handle reordering for adaptive routing to work.
In detail
- NICs must handle reordering for adaptive routing to work.
- Without this, reordering would harm performance.
Use case
An illustrative scenario, not a real incident.
Adaptive routing sends packets by different paths, and the receiving NIC places them correctly.
See it in different ways
flowchart LR A["SuperNIC"] --> B["Spectrum-X switch"] B -->|"Adaptive routing"| C["SuperNIC"] C --> D["Packets placed in order"]
stateDiagram-v2 [*] --> SuperNicSends SuperNicSends --> AdaptiveRouting: switch picks the best path AdaptiveRouting --> OutOfOrder: packets arrive mixed OutOfOrder --> Placed: receiving NIC places them Placed --> [*]
sequenceDiagram participant P0 as Sender participant P1 as Paths participant P2 as Receiving NIC P0->>P1: Packets on many paths P1->>P2: Out of order P2-->>P0: Placed correctly
Key point: Receivers must handle reordering.
Why the other options are wrong
- A. The sender must restart the entire flow
- Restarting would be very slow.
- B. The fabric must fall back to one path
- That loses the benefit.
- D. The switch must drop each late packet
- Dropping would waste the benefit.