cable with multiple connections can't cross module front/rear ports. #11079

ThomasADavis · 2022-12-01T23:14:22Z

NetBox version

v3.3.9

Python version

3.9

Steps to Reproduce

We use a module fiber cassette system - these are cassettes you plug into 1u rack mount.

Trying to plug a MPO to LC breakout cable can cross these modules - the rear ports a single MPO and the front ports are 6 pairs of LC connectors. So the break out cable we use is a 1 MPO (ie, 100G qsfp) to 4 pair of LC's. This can cross between two modules.

create a device. aka 'sw-test'
add to this device a network interface. any type will do, except lag or virtual.
create a module_type, with no components add.
create a device to use as a patch panel.
in that patch panel, create two module bays, 'C1' and 'C2'.
populate the module bay with the above module type.
for module C1 add rear port of 'MPO-1', positions of 6
for module C2 add rear port of 'MPO-2', positions of 6
for module C1, add front ports of 'LC-[1-6]', type 'LC', attached to rear-port MPO-1:[1-6]
for module C2, add front ports of 'LC-[7-12]', type 'LC', attached to rear-port MPO-2:[1-6]

See attached screen shot for module/cassette/front/rear setup.

go to the test device you created.
for the on the network interface, tell it you want to make a connection. Choose front port.

for the termination_b, choose LC-6 (associated with MPO-1) and LC-7 (associated with MPO-2)

Get error message in browser.

Stack dump from our test netbox instance, doing the same thing:

Traceback (most recent call last):
  File "/opt/netbox/venv/lib/python3.10/site-packages/django/core/handlers/exception.py", line 55, in inner
    response = get_response(request)
  File "/opt/netbox/venv/lib/python3.10/site-packages/django/core/handlers/base.py", line 197, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "/opt/netbox/venv/lib/python3.10/site-packages/django/views/decorators/csrf.py", line 54, in wrapped_view
    return view_func(*args, **kwargs)
  File "/opt/netbox/venv/lib/python3.10/site-packages/rest_framework/viewsets.py", line 125, in view
    return self.dispatch(request, *args, **kwargs)
  File "/opt/netbox/netbox/netbox/api/viewsets/__init__.py", line 118, in dispatch
    return super().dispatch(request, *args, **kwargs)
  File "/opt/netbox/venv/lib/python3.10/site-packages/rest_framework/views.py", line 509, in dispatch
    response = self.handle_exception(exc)
  File "/opt/netbox/venv/lib/python3.10/site-packages/rest_framework/views.py", line 469, in handle_exception
    self.raise_uncaught_exception(exc)
  File "/opt/netbox/venv/lib/python3.10/site-packages/rest_framework/views.py", line 480, in raise_uncaught_exception
    raise exc
  File "/opt/netbox/venv/lib/python3.10/site-packages/rest_framework/views.py", line 506, in dispatch
    response = handler(request, *args, **kwargs)
  File "/opt/netbox/venv/lib/python3.10/site-packages/rest_framework/mixins.py", line 19, in create
    self.perform_create(serializer)
  File "/opt/netbox/netbox/netbox/api/viewsets/__init__.py", line 157, in perform_create
    instance = serializer.save()
  File "/opt/netbox/venv/lib/python3.10/site-packages/rest_framework/serializers.py", line 212, in save
    self.instance = self.create(validated_data)
  File "/opt/netbox/netbox/netbox/api/serializers/features.py", line 56, in create
    instance = super().create(validated_data)
  File "/opt/netbox/venv/lib/python3.10/site-packages/rest_framework/serializers.py", line 962, in create
    instance = ModelClass._default_manager.create(**validated_data)
  File "/opt/netbox/venv/lib/python3.10/site-packages/django/db/models/manager.py", line 85, in manager_method
    return getattr(self.get_queryset(), name)(*args, **kwargs)
  File "/opt/netbox/venv/lib/python3.10/site-packages/django/db/models/query.py", line 514, in create
    obj.save(force_insert=True, using=self.db)
  File "/opt/netbox/netbox/dcim/models/cables.py", line 207, in save
    trace_paths.send(Cable, instance=self, created=_created)
  File "/opt/netbox/venv/lib/python3.10/site-packages/django/dispatch/dispatcher.py", line 176, in send
    return [
  File "/opt/netbox/venv/lib/python3.10/site-packages/django/dispatch/dispatcher.py", line 177, in <listcomp>
    (receiver, receiver(signal=self, sender=sender, **named))
  File "/opt/netbox/netbox/dcim/signals.py", line 97, in update_connected_endpoints
    create_cablepath(nodes)
  File "/opt/netbox/netbox/dcim/utils.py", line 43, in create_cablepath
    cp = CablePath.from_origin(terminations)
  File "/opt/netbox/netbox/dcim/models/cables.py", line 543, in from_origin
    assert all(rp.positions == 1 for rp in rear_ports)
AssertionError

Expected Behavior

Can attach a breakout cable across modules/frontports

Observed Behavior

Internal Server Error: /api/dcim/cables/
Traceback (most recent call last):
  File "/opt/netbox/venv/lib/python3.10/site-packages/django/core/handlers/exception.py", line 55, in inner
    response = get_response(request)
  File "/opt/netbox/venv/lib/python3.10/site-packages/django/core/handlers/base.py", line 197, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "/opt/netbox/venv/lib/python3.10/site-packages/django/views/decorators/csrf.py", line 54, in wrapped_view
    return view_func(*args, **kwargs)
  File "/opt/netbox/venv/lib/python3.10/site-packages/rest_framework/viewsets.py", line 125, in view
    return self.dispatch(request, *args, **kwargs)
  File "/opt/netbox/netbox/netbox/api/viewsets/__init__.py", line 118, in dispatch
    return super().dispatch(request, *args, **kwargs)
  File "/opt/netbox/venv/lib/python3.10/site-packages/rest_framework/views.py", line 509, in dispatch
    response = self.handle_exception(exc)
  File "/opt/netbox/venv/lib/python3.10/site-packages/rest_framework/views.py", line 469, in handle_exception
    self.raise_uncaught_exception(exc)
  File "/opt/netbox/venv/lib/python3.10/site-packages/rest_framework/views.py", line 480, in raise_uncaught_exception
    raise exc
  File "/opt/netbox/venv/lib/python3.10/site-packages/rest_framework/views.py", line 506, in dispatch
    response = handler(request, *args, **kwargs)
  File "/opt/netbox/venv/lib/python3.10/site-packages/rest_framework/mixins.py", line 19, in create
    self.perform_create(serializer)
  File "/opt/netbox/netbox/netbox/api/viewsets/__init__.py", line 157, in perform_create
    instance = serializer.save()
  File "/opt/netbox/venv/lib/python3.10/site-packages/rest_framework/serializers.py", line 212, in save
    self.instance = self.create(validated_data)
  File "/opt/netbox/netbox/netbox/api/serializers/features.py", line 56, in create
    instance = super().create(validated_data)
  File "/opt/netbox/venv/lib/python3.10/site-packages/rest_framework/serializers.py", line 962, in create
    instance = ModelClass._default_manager.create(**validated_data)
  File "/opt/netbox/venv/lib/python3.10/site-packages/django/db/models/manager.py", line 85, in manager_method
    return getattr(self.get_queryset(), name)(*args, **kwargs)
  File "/opt/netbox/venv/lib/python3.10/site-packages/django/db/models/query.py", line 514, in create
    obj.save(force_insert=True, using=self.db)
  File "/opt/netbox/netbox/dcim/models/cables.py", line 207, in save
    trace_paths.send(Cable, instance=self, created=_created)
  File "/opt/netbox/venv/lib/python3.10/site-packages/django/dispatch/dispatcher.py", line 176, in send
    return [
  File "/opt/netbox/venv/lib/python3.10/site-packages/django/dispatch/dispatcher.py", line 177, in <listcomp>
    (receiver, receiver(signal=self, sender=sender, **named))
  File "/opt/netbox/netbox/dcim/signals.py", line 97, in update_connected_endpoints
    create_cablepath(nodes)
  File "/opt/netbox/netbox/dcim/utils.py", line 43, in create_cablepath
    cp = CablePath.from_origin(terminations)
  File "/opt/netbox/netbox/dcim/models/cables.py", line 543, in from_origin
    assert all(rp.positions == 1 for rp in rear_ports)
AssertionError

The text was updated successfully, but these errors were encountered:

jeremystretch · 2022-12-02T13:10:40Z

in demo.netbox.dev, do

Per the bug report template:

Additionally, do not rely on the demo instance for reproducing suspected bugs, as its data is prone to modification or deletion at any time.

Please review your post above to ensure that the reproduction steps are not dependent on any data in the demo instance.

armanngu · 2022-12-05T14:09:36Z

I think I have the same or a similar bug.

Steps to Reproduce

a) create a device with interfaces
b) create a patch panel with front and back ports connected (1-1,2-2,etc)
c) connect interface to two front ports.

Observed Behavior

Traceback (most recent call last):
File "/opt/netbox/venv/lib/python3.10/site-packages/django/core/handlers/exception.py", line 55, in inner
response = get_response(request)
File "/opt/netbox/venv/lib/python3.10/site-packages/django/core/handlers/base.py", line 197, in _get_response
response = wrapped_callback(request, *callback_args, **callback_kwargs)
File "/opt/netbox/venv/lib/python3.10/site-packages/django/views/generic/base.py", line 84, in view
return self.dispatch(request, *args, **kwargs)
File "/opt/netbox/netbox/dcim/views.py", line 2786, in dispatch
return super().dispatch(request, *args, **kwargs)
File "/opt/netbox/netbox/netbox/views/generic/object_views.py", line 303, in dispatch
return super().dispatch(request, *args, **kwargs)
File "/opt/netbox/netbox/utilities/views.py", line 90, in dispatch
return super().dispatch(request, *args, **kwargs)
File "/opt/netbox/venv/lib/python3.10/site-packages/django/views/generic/base.py", line 119, in dispatch
return handler(request, *args, **kwargs)
File "/opt/netbox/netbox/netbox/views/generic/object_views.py", line 391, in post
obj = form.save()
File "/opt/netbox/venv/lib/python3.10/site-packages/django/forms/models.py", line 548, in save
self.instance.save()
File "/opt/netbox/netbox/dcim/models/cables.py", line 207, in save
trace_paths.send(Cable, instance=self, created=_created)
File "/opt/netbox/venv/lib/python3.10/site-packages/django/dispatch/dispatcher.py", line 176, in send
return [
File "/opt/netbox/venv/lib/python3.10/site-packages/django/dispatch/dispatcher.py", line 177, in
(receiver, receiver(signal=self, sender=sender, **named))
File "/opt/netbox/netbox/dcim/signals.py", line 97, in update_connected_endpoints
create_cablepath(nodes)
File "/opt/netbox/netbox/dcim/utils.py", line 43, in create_cablepath
cp = CablePath.from_origin(terminations)
File "/opt/netbox/netbox/dcim/models/cables.py", line 543, in from_origin
assert all(rp.positions == 1 for rp in rear_ports)

Exception Type: AssertionError at /dcim/cables/add/
Exception Value:

ThomasADavis · 2022-12-05T18:57:25Z

I've removed all references to any devices/device_type/module types/modules in demo.netbox.dev.

jeremystretch · 2023-01-11T20:47:20Z

There are two issues here:

The unhandled exception
Lack of support for the condition that assert statement is checking for

IIRC, this specific condition was not possible to reach prior to the introduction of multi-termination cabling in v3.3, hence the lack of elegant validation, however it obviously did not get updated.

I presume we can resolve the exception itself fairly easily, however supporting traces that split across multiple multi-position rear ports may be difficult. There's also probably some overlap here with #10602; we should consider these in tandem.

craized · 2023-02-04T00:09:44Z

+1 for supporting this. My use case is different, but I am running into the same AssertError.
Situation is:
Connect a single interface to a MUX with separate TX/RX rear ports.
Breaking cable traces would be sad, but for me allowing the proper modeling of both directions of a span is first priority.

CADbloke · 2023-03-27T01:01:42Z

Related discussion: #11158 in summary, modeling Lanes of QSFP-type connections across breakouts and keeping track of the individual data channels.

mblue-fasttrack · 2023-03-28T16:25:32Z

Issue only occurs when the cable is attached to an interface. Attaching a cable from front or rear ports to other multiple front ports linked to different, multi-position rear ports does not raise an exception.

DanSheps · 2023-08-01T16:47:28Z

I am going to try and take this up by simply catching the exception. We can then discuss supported and unsupported topologies in a separate FR.

…3337) * Catch AssertionError's in signals. Handle accordingly * Alter cable logic to handle certain additional path types. * Fix failures and add test * More tests * Remove not needed tests, add additional tests * Finish tests, correct some behaviour * Add check for mid-span device not allowed condition * Remove excess import * Remove logging import * Remove logging import * Minor tweaks based on Arthur's feedback * Update netbox/dcim/tests/test_cablepaths.py Co-authored-by: Jeremy Stretch <jstretch@netboxlabs.com> * Update netbox/dcim/models/cables.py Co-authored-by: Jeremy Stretch <jstretch@netboxlabs.com> * Changes to account for required SVG rendering changes and based on feedback * More tweaks for cable path checking * Improve handling of links with multi-terminations * Improved SVG rendering of multiple rear ports (with positions) per path trace. Include asymmetric path detection * Include missing assert to ensure links are same type. * Clean up tests * Remove unused objects from tests * Changes requested to tests and update comments/doctstrings * Fix parent reference --------- Co-authored-by: Jeremy Stretch <jstretch@netboxlabs.com>

ThomasADavis added the type: bug A confirmed report of unexpected behavior in the application label Dec 1, 2022

jeremystretch added the status: revisions needed This issue requires additional information to be actionable label Dec 2, 2022

jeremystretch added topic: cabling status: accepted This issue has been accepted for implementation and removed status: revisions needed This issue requires additional information to be actionable labels Jan 6, 2023

jeremystretch self-assigned this Jan 11, 2023

jsenecal self-assigned this May 4, 2023

jeremystretch added the severity: medium Results in substantial degraded or broken functionality for specfic workflows label Jun 23, 2023

DanSheps assigned DanSheps and unassigned jsenecal and jeremystretch Aug 1, 2023

This was referenced Aug 1, 2023

Fixes: #11079 - Handle cables across multiple rear-port positions #13337

Merged

Not Paths Found on cable tracing of Rear Ports with Modules #12025

Closed

Missing cable trace when multi termination cables. #10602

Open

jeremystretch mentioned this issue Sep 21, 2023

Multi-termination jumper deletion creates front port inconsistency #11667

Closed

jeremystretch closed this as completed in #13337 Sep 26, 2023

jeremystretch mentioned this issue Sep 26, 2023

Full trace with splitter cable between patch panels #13865

Closed

jeremystretch added a commit that referenced this issue Sep 26, 2023

Changelog for #11079, #11901, #13843, #13849, #13859, #13864

1a00765

jeremystretch mentioned this issue Sep 26, 2023

Release v3.6.3 #13907

Merged

ThomasADavis mentioned this issue Oct 3, 2023

Unable to create multi-termination cable between rear ports if front occupied #13930

Closed

github-actions bot locked as resolved and limited conversation to collaborators Dec 26, 2023

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cable with multiple connections can't cross module front/rear ports. #11079

cable with multiple connections can't cross module front/rear ports. #11079

ThomasADavis commented Dec 1, 2022 •

edited

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jeremystretch commented Dec 2, 2022

armanngu commented Dec 5, 2022

ThomasADavis commented Dec 5, 2022

jeremystretch commented Jan 11, 2023

craized commented Feb 4, 2023

CADbloke commented Mar 27, 2023

mblue-fasttrack commented Mar 28, 2023

DanSheps commented Aug 1, 2023 •

edited

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cable with multiple connections can't cross module front/rear ports. #11079

cable with multiple connections can't cross module front/rear ports. #11079

Comments

ThomasADavis commented Dec 1, 2022 • edited Loading

NetBox version

Python version

Steps to Reproduce

Expected Behavior

Observed Behavior

jeremystretch commented Dec 2, 2022

armanngu commented Dec 5, 2022

Steps to Reproduce

Observed Behavior

ThomasADavis commented Dec 5, 2022

jeremystretch commented Jan 11, 2023

craized commented Feb 4, 2023

CADbloke commented Mar 27, 2023

mblue-fasttrack commented Mar 28, 2023

DanSheps commented Aug 1, 2023 • edited Loading

ThomasADavis commented Dec 1, 2022 •

edited

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DanSheps commented Aug 1, 2023 •

edited

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