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Root cause analysis / Investigation

copilot.com

Reference RCA-30B14E488C713C6A

Microsoft Chat website

Measurement point: Stealth NYC, 32 Avenue of the Americas.

Published investigation. Updates run automatically.

01 / Network path

Network path.

Endpoint measurements / ICMP IPv4

Latency over time.

Successful endpoint RTT recordings from up to one hour before and after the event.

Enter time range

Times use the selected timezone; choices include recorded samples and intervals across the available chart.

Use the recordings table below to view latency values.
Successful RTT recording Event interval

04 Nov 2026 01:55 – 04 Nov 2026 04:54 UTC. Hover or tap to inspect; drag across the chart to zoom. On touchscreens, first choose Select time range. Escape or Reset zoom restores the full range. Missing recordings are gaps; this is not an application availability or packet-loss chart.

Select a recording to explore nearby path observations.

View recorded values
Successful ICMP IPv4 RTT recordings.
Recorded at (UTC)RTT
22.854 ms
22.856 ms
22.781 ms
22.903 ms
22.818 ms
22.818 ms
22.821 ms
22.838 ms
22.858 ms
22.807 ms
22.809 ms
22.887 ms
22.835 ms
22.845 ms
23.055 ms
22.863 ms
22.840 ms
22.789 ms
22.867 ms
22.441 ms
22.346 ms
22.403 ms
22.406 ms
22.371 ms
22.398 ms
6.253 ms
6.308 ms
6.237 ms
6.326 ms
6.270 ms
6.284 ms
6.268 ms
6.274 ms
6.277 ms
6.267 ms
6.254 ms
6.273 ms
6.317 ms
6.125 ms
6.149 ms
6.131 ms
6.131 ms
6.124 ms
6.144 ms
6.336 ms
6.282 ms
6.285 ms
6.258 ms
6.302 ms
6.265 ms
6.296 ms
6.245 ms
6.269 ms
6.273 ms
6.267 ms
6.302 ms
6.115 ms
6.147 ms
6.139 ms
6.120 ms
6.144 ms
6.210 ms
6.251 ms
6.802 ms
6.266 ms
6.328 ms
6.319 ms
6.290 ms
6.261 ms
6.198 ms
6.141 ms
6.134 ms
6.119 ms
6.173 ms
6.141 ms
6.187 ms
6.161 ms
6.137 ms
6.149 ms
6.176 ms
6.164 ms
6.155 ms
6.144 ms
6.184 ms
6.153 ms
6.120 ms
6.149 ms
6.177 ms
6.140 ms
6.152 ms
6.239 ms
6.174 ms
6.172 ms
6.132 ms
6.126 ms
6.124 ms
6.123 ms
6.132 ms
6.572 ms
6.545 ms
6.522 ms
6.539 ms
6.548 ms
6.525 ms
6.567 ms
6.663 ms
6.551 ms
6.541 ms
6.540 ms
6.569 ms
6.582 ms
6.737 ms
6.724 ms
6.749 ms
6.722 ms
6.729 ms
6.729 ms
6.760 ms
6.735 ms
6.735 ms
22.821 ms
22.894 ms
22.867 ms
22.892 ms
22.842 ms
22.842 ms
22.894 ms
22.799 ms
22.799 ms
22.866 ms
22.832 ms
22.807 ms
22.955 ms
22.864 ms
22.797 ms
22.805 ms
22.848 ms
22.880 ms
22.831 ms
22.813 ms
22.837 ms
22.816 ms
22.820 ms
22.850 ms
22.846 ms
22.891 ms
22.853 ms
22.457 ms
22.452 ms
22.388 ms
22.401 ms
22.373 ms
22.377 ms
22.842 ms
22.817 ms
22.811 ms
22.828 ms
22.850 ms
22.850 ms
22.965 ms
22.810 ms
22.863 ms
22.845 ms
22.907 ms
22.815 ms
22.814 ms
22.853 ms
22.866 ms
22.836 ms
22.895 ms
22.830 ms
22.831 ms
22.847 ms
22.834 ms
22.881 ms
22.862 ms
22.863 ms
22.860 ms
22.887 ms
22.838 ms
22.816 ms
22.853 ms
22.891 ms
22.881 ms
22.807 ms
22.824 ms
31.144 ms
31.140 ms
31.115 ms
31.095 ms
31.146 ms
27.598 ms
27.616 ms
27.598 ms
27.599 ms
27.579 ms
27.616 ms
27.632 ms
21.875 ms
21.948 ms
21.927 ms
21.910 ms
21.925 ms
21.887 ms
6.782 ms
6.784 ms
6.736 ms
6.783 ms
6.747 ms
6.743 ms
6.740 ms
6.771 ms
6.757 ms
6.780 ms
6.746 ms
6.796 ms
6.756 ms
6.899 ms
6.869 ms
6.849 ms
6.894 ms
6.874 ms
6.865 ms
6.859 ms
6.893 ms
6.869 ms
6.871 ms
6.926 ms
6.869 ms
6.867 ms
6.858 ms
6.853 ms
6.847 ms
6.970 ms
6.854 ms
6.874 ms
6.851 ms
6.907 ms
6.879 ms
6.920 ms
6.856 ms
6.855 ms
6.891 ms
6.936 ms
6.913 ms
6.923 ms
6.872 ms
6.869 ms
6.871 ms
6.893 ms
6.890 ms
6.878 ms
6.852 ms
6.850 ms
6.840 ms
6.782 ms
6.730 ms
6.762 ms
6.755 ms
6.815 ms
6.713 ms
6.733 ms
6.725 ms
6.729 ms
6.771 ms
6.726 ms
6.759 ms
6.748 ms
6.724 ms
6.746 ms
6.736 ms
6.774 ms
6.746 ms
6.799 ms
6.729 ms
6.841 ms
22.821 ms
22.812 ms
22.896 ms
22.876 ms
22.851 ms
22.802 ms
22.877 ms
22.877 ms
22.834 ms
22.872 ms
22.911 ms
22.890 ms
22.849 ms
22.901 ms
22.872 ms
22.818 ms
22.865 ms
22.858 ms
22.840 ms
22.899 ms
22.863 ms
22.850 ms
22.815 ms
22.864 ms
22.878 ms
22.847 ms
22.889 ms
22.864 ms
22.916 ms
22.864 ms
22.885 ms
22.803 ms
22.820 ms
22.826 ms
22.828 ms
22.934 ms
22.849 ms
22.796 ms
22.854 ms
22.862 ms
22.822 ms
22.905 ms
22.815 ms
22.930 ms
31.243 ms
22.815 ms
22.808 ms
22.878 ms
22.869 ms
22.812 ms
27.617 ms
27.625 ms
27.601 ms
27.620 ms
27.562 ms
27.554 ms
27.559 ms
27.598 ms
27.578 ms
27.554 ms
27.613 ms
27.609 ms
27.570 ms
27.604 ms
27.583 ms
27.578 ms
27.597 ms
27.612 ms
27.569 ms
27.594 ms
27.612 ms
27.578 ms
27.582 ms
27.635 ms
27.623 ms
27.548 ms
27.597 ms
27.602 ms
27.567 ms
27.543 ms
27.675 ms
27.595 ms
Network path / recorded observations

Network path observations.

17 observations

Choose a measurement type to see the closest of the available sampled observations to the selected chart point. Each probe is separate and may follow a different path.

Before

ICMP traceroute · Recorded address 4

Recorded trace · destination not reached by this trace


to UTC

  1. TTL 1 Probe hop0.119 msReply RTT AS8002 · Stealth
  2. TTL 2 Probe hop0.928 msReply RTT AS8075 · Microsoft
Before

TCP traceroute / 443 · Recorded address 4

Recorded trace · destination replied


to UTC

  1. TTL 1 Probe hop0.207 msReply RTT AS8002 · Stealth
  2. TTL 2 Probe hop4.107 msReply RTT AS8075 · Microsoft
  3. TTL 3 Probe hop1.759 msReply RTT AS8075 · Microsoft
  4. TTL 4 Probe hop23.686 msReply RTT AS8075 · Microsoft
  5. TTL 5 Probe hop23.638 msReply RTT AS8075 · Microsoft
  6. TTL 6 Probe hop23.487 msReply RTT AS8075 · Microsoft
  7. TTL 7 Probe hop23.278 msReply RTT AS8075 · Microsoft
  8. TTL 8 Probe hopNo replyNo comparable RTT ASN unavailable
  9. TTL 9 Probe hop23.585 msReply RTT AS8075 · Microsoft
  10. TTL 10 Probe hop20.130 msReply RTT AS8075 · Microsoft
  11. TTL 11 Probe hop23.096 msReply RTT AS8075 · Microsoft
  12. TTL 12 Probe hopNo replyNo comparable RTT ASN unavailable
  13. TTL 13 Destination22.894 msReply RTT AS8075 · Microsoft
Before

ICMP traceroute · Recorded address 1

Recorded trace · destination not reached by this trace


to UTC

  1. TTL 1 Probe hop0.338 msReply RTT AS8002 · Stealth
Before

TCP traceroute / 443 · Recorded address 1

Recorded trace · destination replied


to UTC

  1. TTL 1 Probe hop0.168 msReply RTT AS8002 · Stealth
  2. TTL 2 Probe hop1.043 msReply RTT ASN unavailable
  3. TTL 3 Probe hopNo replyNo comparable RTT ASN unavailable
  4. TTL 4 Probe hop7.221 msReply RTT AS8075 · Microsoft
  5. TTL 5 Probe hop8.033 msReply RTT AS8075 · Microsoft
  6. TTL 6 Probe hop7.691 msReply RTT AS8075 · Microsoft
  7. TTL 7 Probe hop7.262 msReply RTT AS8075 · Microsoft
  8. TTL 8 Probe hopNo replyNo comparable RTT ASN unavailable
  9. TTL 9 Probe hopNo replyNo comparable RTT ASN unavailable
  10. TTL 10 Probe hopNo replyNo comparable RTT ASN unavailable
  11. TTL 11 Probe hopNo replyNo comparable RTT ASN unavailable
  12. TTL 12 Destination6.637 msReply RTT AS8075 · Microsoft
Before

TCP traceroute / 443 · Recorded address 2

Recorded trace · destination replied


to UTC

  1. TTL 1 Probe hop0.150 msReply RTT AS8002 · Stealth
  2. TTL 2 Probe hop0.847 msReply RTT ASN unavailable
  3. TTL 3 Probe hop0.826 msReply RTT AS8075 · Microsoft
  4. TTL 4 Probe hop6.992 msReply RTT AS8075 · Microsoft
  5. TTL 5 Probe hop8.213 msReply RTT AS8075 · Microsoft
  6. TTL 6 Probe hop8.325 msReply RTT AS8075 · Microsoft
  7. TTL 7 Probe hop8.339 msReply RTT AS8075 · Microsoft
  8. TTL 8 Probe hopNo replyNo comparable RTT ASN unavailable
  9. TTL 9 Probe hopNo replyNo comparable RTT ASN unavailable
  10. TTL 10 Probe hopNo replyNo comparable RTT ASN unavailable
  11. TTL 11 Probe hopNo replyNo comparable RTT ASN unavailable
  12. TTL 12 Destination6.654 msReply RTT AS8075 · Microsoft
During

ICMP traceroute · Recorded address 4

Recorded trace · destination not reached by this trace


to UTC

  1. TTL 1 Probe hop0.123 msReply RTT AS8002 · Stealth
During

TCP traceroute / 443 · Recorded address 4

Recorded trace · destination replied


to UTC

  1. TTL 1 Probe hop0.145 msReply RTT AS8002 · Stealth
  2. TTL 2 Probe hopNo replyNo comparable RTT ASN unavailable
  3. TTL 3 Probe hop2.325 msReply RTT AS8075 · Microsoft
  4. TTL 4 Probe hopNo replyNo comparable RTT ASN unavailable
  5. TTL 5 Probe hop23.709 msReply RTT AS8075 · Microsoft
  6. TTL 6 Probe hop24.092 msReply RTT AS8075 · Microsoft
  7. TTL 7 Probe hop24.657 msReply RTT AS8075 · Microsoft
  8. TTL 8 Probe hop23.835 msReply RTT AS8075 · Microsoft
  9. TTL 9 Probe hop26.308 msReply RTT AS8075 · Microsoft
  10. TTL 10 Probe hop19.945 msReply RTT AS8075 · Microsoft
  11. TTL 11 Probe hop23.017 msReply RTT AS8075 · Microsoft
  12. TTL 12 Probe hopNo replyNo comparable RTT ASN unavailable
  13. TTL 13 Destination22.989 msReply RTT AS8075 · Microsoft
During

ICMP traceroute · Recorded address 4

Recorded trace · destination not reached by this trace


to UTC

  1. TTL 1 Probe hop0.135 msReply RTT AS8002 · Stealth
  2. TTL 2 Probe hop0.947 msReply RTT AS8075 · Microsoft
During

TCP traceroute / 443 · Recorded address 4

Recorded trace · destination replied


to UTC

  1. TTL 1 Probe hop0.168 msReply RTT AS8002 · Stealth
  2. TTL 2 Probe hop22.400 msReply RTT AS8075 · Microsoft
  3. TTL 3 Probe hop1.721 msReply RTT AS8075 · Microsoft
  4. TTL 4 Probe hop23.412 msReply RTT AS8075 · Microsoft
  5. TTL 5 Probe hop23.943 msReply RTT AS8075 · Microsoft
  6. TTL 6 Probe hop24.752 msReply RTT AS8075 · Microsoft
  7. TTL 7 Probe hop24.607 msReply RTT AS8075 · Microsoft
  8. TTL 8 Probe hopNo replyNo comparable RTT ASN unavailable
  9. TTL 9 Probe hop23.737 msReply RTT AS8075 · Microsoft
  10. TTL 10 Probe hop20.091 msReply RTT AS8075 · Microsoft
  11. TTL 11 Probe hop52.634 msReply RTT AS8075 · Microsoft
  12. TTL 12 Probe hopNo replyNo comparable RTT ASN unavailable
  13. TTL 13 Destination22.908 msReply RTT AS8075 · Microsoft
During

ICMP traceroute · Recorded address 3

Recorded trace · destination not reached by this trace


to UTC

  1. TTL 1 Probe hop0.144 msReply RTT AS8002 · Stealth
  2. TTL 2 Probe hop32.929 msReply RTT AS8075 · Microsoft
During

TCP traceroute / 443 · Recorded address 3

Recorded trace · destination replied


to UTC

  1. TTL 1 Probe hop0.175 msReply RTT AS8002 · Stealth
  2. TTL 2 Probe hop1.723 msReply RTT AS8075 · Microsoft
  3. TTL 3 Probe hopNo replyNo comparable RTT ASN unavailable
  4. TTL 4 Probe hop6.786 msReply RTT AS8075 · Microsoft
  5. TTL 5 Probe hop8.183 msReply RTT AS8075 · Microsoft
  6. TTL 6 Probe hop7.654 msReply RTT AS8075 · Microsoft
  7. TTL 7 Probe hopNo replyNo comparable RTT ASN unavailable
  8. TTL 8 Probe hopNo replyNo comparable RTT ASN unavailable
  9. TTL 9 Probe hopNo replyNo comparable RTT ASN unavailable
  10. TTL 10 Probe hopNo replyNo comparable RTT ASN unavailable
  11. TTL 11 Destination6.750 msReply RTT AS8075 · Microsoft
After

ICMP traceroute · Recorded address 3

Recorded trace · destination not reached by this trace


to UTC

  1. TTL 1 Probe hop0.125 msReply RTT AS8002 · Stealth
After

TCP traceroute / 443 · Recorded address 3

Recorded trace · destination replied


to UTC

  1. TTL 1 Probe hop0.600 msReply RTT AS8002 · Stealth
  2. TTL 2 Probe hopNo replyNo comparable RTT ASN unavailable
  3. TTL 3 Probe hopNo replyNo comparable RTT ASN unavailable
  4. TTL 4 Probe hop7.740 msReply RTT AS8075 · Microsoft
  5. TTL 5 Probe hop7.749 msReply RTT AS8075 · Microsoft
  6. TTL 6 Probe hop8.489 msReply RTT AS8075 · Microsoft
  7. TTL 7 Probe hop6.320 msReply RTT AS8075 · Microsoft
  8. TTL 8 Probe hopNo replyNo comparable RTT ASN unavailable
  9. TTL 9 Probe hopNo replyNo comparable RTT ASN unavailable
  10. TTL 10 Probe hopNo replyNo comparable RTT ASN unavailable
  11. TTL 11 Probe hopNo replyNo comparable RTT ASN unavailable
  12. TTL 12 Destination7.029 msReply RTT AS8075 · Microsoft
After

ICMP traceroute · Recorded address 4

Recorded trace · destination not reached by this trace


to UTC

  1. TTL 1 Probe hop0.148 msReply RTT AS8002 · Stealth
  2. TTL 2 Probe hop0.930 msReply RTT AS8075 · Microsoft
  3. TTL 3 Probe hop1.380 msReply RTT AS8075 · Microsoft
  4. TTL 4 Probe hop23.538 msReply RTT AS8075 · Microsoft
  5. TTL 5 Probe hop24.001 msReply RTT AS8075 · Microsoft
  6. TTL 6 Probe hop23.605 msReply RTT AS8075 · Microsoft
  7. TTL 7 Probe hop24.684 msReply RTT AS8075 · Microsoft
After

TCP traceroute / 443 · Recorded address 4

Recorded trace · destination replied


to UTC

  1. TTL 1 Probe hop0.164 msReply RTT AS8002 · Stealth
  2. TTL 2 Probe hop1.119 msReply RTT AS8075 · Microsoft
  3. TTL 3 Probe hopNo replyNo comparable RTT ASN unavailable
  4. TTL 4 Probe hop23.475 msReply RTT AS8075 · Microsoft
  5. TTL 5 Probe hop23.368 msReply RTT AS8075 · Microsoft
  6. TTL 6 Probe hop23.466 msReply RTT AS8075 · Microsoft
  7. TTL 7 Probe hop24.048 msReply RTT AS8075 · Microsoft
  8. TTL 8 Probe hopNo replyNo comparable RTT ASN unavailable
  9. TTL 9 Probe hop23.723 msReply RTT AS8075 · Microsoft
  10. TTL 10 Probe hop20.008 msReply RTT AS8075 · Microsoft
  11. TTL 11 Probe hop22.951 msReply RTT AS8075 · Microsoft
  12. TTL 12 Probe hopNo replyNo comparable RTT ASN unavailable
  13. TTL 13 Destination22.925 msReply RTT AS8075 · Microsoft
After

ICMP traceroute · Recorded address 4

Recorded trace · destination not reached by this trace


to UTC

  1. TTL 1 Probe hop0.293 msReply RTT AS8002 · Stealth
  2. TTL 2 Probe hop0.838 msReply RTT AS8075 · Microsoft
  3. TTL 3 Probe hop1.248 msReply RTT AS8075 · Microsoft
  4. TTL 4 Probe hop28.407 msReply RTT AS8075 · Microsoft
  5. TTL 5 Probe hop28.425 msReply RTT AS8075 · Microsoft
  6. TTL 6 Probe hop24.740 msReply RTT AS8075 · Microsoft
  7. TTL 7 Probe hop27.736 msReply RTT AS8075 · Microsoft
After

TCP traceroute / 443 · Recorded address 4

Recorded trace · destination replied


to UTC

  1. TTL 1 Probe hop0.149 msReply RTT AS8002 · Stealth
  2. TTL 2 Probe hop2.909 msReply RTT AS8075 · Microsoft
  3. TTL 3 Probe hop1.170 msReply RTT AS8075 · Microsoft
  4. TTL 4 Probe hop28.238 msReply RTT AS8075 · Microsoft
  5. TTL 5 Probe hop28.266 msReply RTT AS8075 · Microsoft
  6. TTL 6 Probe hop24.709 msReply RTT AS8075 · Microsoft
  7. TTL 7 Probe hop27.794 msReply RTT AS8075 · Microsoft
  8. TTL 8 Probe hopNo replyNo comparable RTT ASN unavailable
  9. TTL 9 Destination27.752 msReply RTT AS8075 · Microsoft

RTT is the round trip to each responding hop, not the delay of the preceding link. TTL order may omit routers and does not prove direct links. A missing reply is not proof of packet loss. ASN labels are dated address associations; they do not establish the forwarding path or the operator at the event time. Up to three recorded traces per method and period are selected across the archive. Where no individual trace is available, a comparison may summarize a window; MTR observations aggregate multiple probes. Address aliases are independent across measurement types.

Same method / same recorded address

Compare the traces.

Compare one selected trace from before the event with one during it. Values are individual replies, not a statistical comparison.

ICMP traceroute · Recorded address 4

Before: UTC · During: UTC

Same destination address and probe method. A matching TTL does not establish the same forwarding path.
TTLBefore RTTDuring RTTResponding address
10.119 msAS8002 · Stealth0.123 msAS8002 · StealthSame responder
20.928 msAS8075 · MicrosoftNot recordedNot established
TCP traceroute / 443 · Recorded address 4

Before: UTC · During: UTC

Same destination address and probe method. A matching TTL does not establish the same forwarding path.
TTLBefore RTTDuring RTTResponding address
10.207 msAS8002 · Stealth0.145 msAS8002 · StealthSame responder
24.107 msAS8075 · MicrosoftNo replyNot established
31.759 msAS8075 · Microsoft2.325 msAS8075 · MicrosoftSame responder
423.686 msAS8075 · MicrosoftNo replyNot established
523.638 msAS8075 · Microsoft23.709 msAS8075 · MicrosoftSame responder
623.487 msAS8075 · Microsoft24.092 msAS8075 · MicrosoftSame responder
723.278 msAS8075 · Microsoft24.657 msAS8075 · MicrosoftSame responder
8No reply23.835 msAS8075 · MicrosoftNot established
923.585 msAS8075 · Microsoft26.308 msAS8075 · MicrosoftSame responder
1020.130 msAS8075 · Microsoft19.945 msAS8075 · MicrosoftSame responder
1123.096 msAS8075 · Microsoft23.017 msAS8075 · MicrosoftSame responder
12No replyNo replyNot established
1322.894 msAS8075 · Microsoft22.989 msAS8075 · MicrosoftSame responder

RTTs include the return path. Different responders, missing replies and independent probe flows limit what a change can localize. MTR snapshots remain separate in the replay.

Event timeline.

Possible SLA event. Times shown are UTC.

Event opened
UTC
Last event observation
UTC
Recovery observed
UTC

Recorded recovery describes this event, not current reachability.

02 / Assessment

Assessment.

Investigation stateRecovered
Path assessment

Elevated latency observed.

Endpoint round-trip time was elevated during part of the event. The available path observations do not identify where the increase occurred.

What we observed

  • A sustained increase in measured round trip time was observed.
  • The measured destination address changed across the comparison period.

Recording counts describe collected measurements, not application availability or packet loss. Exact packet paths and the return path remain unverified.

Measurements at a glance.

Baseline RTT6.676 msUsual round trip before the event
Last recorded event RTT6.879 msLast successful event recording
Event p95 RTT27.617 ms95th percentile of successful recordings
Change from baseline+0.203 msLast event RTT compared with the baseline
Successful / expected recordings120 / 120Recorded endpoint samples during the event

RTT is round trip time; p95 describes the upper range of successful recordings. Endpoint measurements differ from individual trace replies and are not an uptime percentage.

Record sources and timestamps
Analysis updated
UTC
Public snapshot published
UTC
Public observation window
– UTC

Event and source timestamps are UTC. The latency chart uses its selected timezone. Page refresh times are separate from measurement timestamps.

03 / Method and limits

Method and limits.

How to interpret the sampled path and its limits

Corroborating the path.

Comparisons use matching destinations before and during the event. ICMP traces use echo probes. TCP/443 traces send SYN probes to port 443 only; they do not complete a TCP handshake or perform a TLS or HTTP exchange.

The Stealth gNMI interface verifies the active route-table choice and maps its primary next hop to the Stealth logical interface, configured attachment and, where applicable, the known LAG member set at each snapshot. Stable Stealth replies, together with mapped interface evidence showing no corresponding errors or sustained capacity pressure, reduce the likelihood of a Stealth forwarding issue. An 80% load warning warrants investigation; it does not prove congestion. Lower interval averages can conceal bursts or queue pressure. Optical readings assess the physical link, not congestion.

What remains unseen.

Probe reply handling can differ from packet forwarding. A slow intermediate reply that disappears at later hops does not locate a forwarding problem. A destination that does not respond to a trace is not thereby shown to be unavailable.

Stealth does not use ECMP in this monitored scope. The route snapshot does not identify which physical LAG member carried a particular independent probe, attest line-card forwarding at that packet instant, prove the exact application packet flow or observe the return path. RTT includes the return path, which may differ. No remote reverse traceroute is available. Tunnels and silent routers may hide parts of the path. Address registration alone does not establish the forwarding operator or responsibility.

References: ICMP reply handling / RFC 1812 · Round trip measurements / RFC 2681 · Full methodology