my shitty notes I've asked AI to clean up and reorder so that they are readable

It is just work in progress so I don't really car
2026-09-07 00:27:05 +02:00
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+# Cisco Nexus C93180LC-EX PTP Boundary Clock
+
+NYATER is the second boundary clock in the PTP chain.
+
+```text
+RPi5 GM
+  │
+  ▼
+WOLF-HUNTER BC
+  │              │
+  │ two QSFP+    │
+  ▼              ▼
+Eth1/5        Eth1/6
+      NYATER
+ C93180LC-EX BC
+      │
+      ├─ PTP client-facing ports
+      └─ PTP client-facing ports
+```
+
+With the current design:
+
+```text
+RPi5            stepsRemoved 0
+WOLF-HUNTER     stepsRemoved 1
+NYATER          stepsRemoved 2
+Linux client    stepsRemoved 3
+```
+
+The current Nexus configuration is stored in `NYATER.ios` in the root of the PTP directory.
+
+## 1. Base configuration
+
+`NYATER.ios` contains:
+
+```text
+feature ptp
+
+ptp device-type boundary-clock
+ptp domain 0
+ptp source 10.255.254.255
+
+interface Ethernet1/5
+  ptp
+
+interface Ethernet1/6
+  ptp
+```
+
+`10.255.254.255` is the address selected as the Nexus PTP source address. In this setup it is the `lo0` address; using the loopback gives PTP packets originated by NYATER a stable source address independent of which physical upstream path is selected.
+
+Before applying the PTP config, verify that the address really exists on NYATER:
+
+```text
+show ip interface brief | include 10.255.254.255
+show running-config interface loopback0
+```
+
+## 2. Apply the base PTP configuration
+
+Enter configuration mode and apply the contents of `NYATER.ios`, or paste the equivalent configuration manually:
+
+```text
+configure terminal
+
+feature ptp
+
+ptp device-type boundary-clock
+ptp domain 0
+ptp source 10.255.254.255
+
+interface Ethernet1/5
+  ptp
+
+interface Ethernet1/6
+  ptp
+
+end
+copy running-config startup-config
+```
+
+`Ethernet1/5` and `Ethernet1/6` are the two links from WOLF-HUNTER's Mellanox ports.
+
+## 3. Expected upstream behavior
+
+When both WOLF-HUNTER links are healthy, NYATER should select one as the active upstream PTP port and leave the other as the redundant path.
+
+Expected output:
+
+```text
+show ptp brief
+
+PTP port status
+-----------------------------------
+Port                  State
+--------------------- ------------
+Eth1/5                Slave
+Eth1/6                Passive
+```
+
+The exact choice may be reversed; `Eth1/6 Slave` and `Eth1/5 Passive` is equally valid.
+
+The important points are:
+
+```text
+- one WOLF-facing port is Slave
+- the other WOLF-facing port is Passive
+- PTP Clock state is Locked
+- grandmaster identity is still the RPi5
+- steps removed is 2
+- domain is 0
+- UTC offset received in Announce packets is 37
+```
+
+## 4. Add a downstream PTP client
+
+For a normal Linux server connected directly to a physical Nexus port, enable PTP on that port:
+
+```text
+configure terminal
+
+interface Ethernet1/<clientPort>
+  ptp
+
+end
+copy running-config startup-config
+```
+
+For example:
+
+```text
+interface Ethernet1/10
+  ptp
+```
+
+No separate per-client PTP source address is required. The existing global:
+
+```text
+ptp source 10.255.254.255
+```
+
+continues to be used by NYATER.
+
+Once the downstream Linux client is active and the Nexus is locked upstream, that client-facing port should normally appear as `Master`.
+
+Example:
+
+```text
+show ptp brief
+
+Eth1/5     Slave
+Eth1/6     Passive
+Eth1/10    Master
+```
+
+Repeat only the interface-level `ptp` command for every additional direct downstream client port.
+
+## 5. Verification commands
+
+The most useful operational commands are:
+
+```text
+show ptp clock
+show ptp brief
+show ptp packet
+```
+
+Your healthy output should resemble:
+
+```text
+PTP Device Type        : boundary-clock
+PTP Source IP Address  : 10.255.254.255
+Clock Domain           : 0
+PTP Clock state        : Locked
+Steps removed          : 2
+```
+
+`show ptp packet` is useful for confirming that Announce packets still carry the RPi5 grandmaster identity and the expected UTC offset:
+
+```text
+gm_id=<RPi5 clock identity>
+utc_offset=37
+```
+
+It also exposes Sync, Follow_Up, Delay_Req and Delay_Resp traffic and is useful when investigating offset or path-delay behavior.
+
+## 6. Current known-good state
+
+A known-good state observed on NYATER had:
+
+```text
+PTP Device Type       : boundary-clock
+PTP Source IP Address : 10.255.254.255
+Clock Domain          : 0
+PTP Clock state       : Locked
+Steps removed         : 2
+Eth1/5                : Slave
+Eth1/6                : Passive
+gm_id                 : 88a29efffe826ce6
+utc_offset            : 37
+```
+
+Use that as a topology sanity check. The active/passive physical ports may swap, but the grandmaster identity should not change merely because the redundant path changes.
+
+## 7. What the `ptp source` address does
+
+The `ptp source 10.255.254.255` setting selects the source IP address used by PTP/UDP packets originated by NYATER. It does **not** mean the Nexus gets its time from `lo0`.
+
+The actual timing reference is still selected by PTP/BMCA through the WOLF-HUNTER-facing ports:
+
+```text
+RPi5 -> WOLF-HUNTER -> NYATER
+```
+
+## 8. Troubleshooting
+
+If NYATER is not locked:
+
+```text
+show ptp clock
+show ptp brief
+show ptp packet
+show interface Ethernet1/5
+show interface Ethernet1/6
+```
+
+Check that:
+
+```text
+- `feature ptp` is enabled
+- domain is 0 everywhere
+- both WOLF-facing ports have `ptp`
+- one upstream port receives Announce/Sync packets
+- the received gm_id is the RPi5 identity
+- WOLF-HUNTER itself is synchronized upstream
+```
+
+If a downstream client is not synchronizing, first confirm its Nexus port has the interface-level `ptp` command and appears as `Master` in `show ptp brief`.