The set-up 
==========

I set up a Pi Zero running Stretch Lite, and connected it via USB in OTG mode to a MacBook.

I successfully found it at ``raspberrypi.local`` from the Macintosh, was able to ssh in, install various packages and run a small Python application.

The problem
===========

While the application was running, it seems to have dropped off the network with a ``broken pipe``:

    pi@raspberrypi:~ $ packet_write_wait: Connection to fe80::a648:c9cc:e29b:761e%bridge100 port 22: Broken pipe

More information
================

I can no longer resolve ``raspberrypi.local`` from the Macintosh. The output of ``arp -a`` shows no sign of it (I think it would have been on a 192.168.2.x address):

    ➜  ~ arp -a   
    dsldevice.lan (192.168.1.1) at c4:ea:1d:6c:bd:ae on en0 ifscope [ethernet]
    danieles-mbp.lan (192.168.1.137) at b8:e8:56:34:97:12 on en0 ifscope permanent [ethernet]
    ? (192.168.1.255) at ff:ff:ff:ff:ff:ff on en0 ifscope [ethernet]
    ? (224.0.0.251) at 1:0:5e:0:0:fb on en0 ifscope permanent [ethernet]
    ? (224.6.7.8) at 1:0:5e:6:7:8 on en0 ifscope permanent [ethernet]
    ? (239.255.255.250) at 1:0:5e:7f:ff:fa on en0 ifscope permanent [ethernet]
    broadcasthost (255.255.255.255) at ff:ff:ff:ff:ff:ff on en0 ifscope [ethernet]

I know that **the Pi hasn't crashed or stop working**, because it has three servos connected to it and they went on doing what they were supposed to until they had finished ten or so minutes later.

The Pi remained powered up over USB, and apparently fully working in every respect except for the networking I need to communicate with it.

What could have disrupted the local OTG network connection?