NAV should prefer LLDP over CDP for these things. If the candidate neighbor list shows both LLDP and CDP entries NAV should use the LLDP data. However NAV will check that the LLDP data matches in both ends. If there are matching LLDP records in both ends and NAV does not use them, then there must be a bug in NAV. If there are no LLDP records in the candidate neighbor list then it is probably turned off on the devices.

More things to consider:
Are you using link aggregation for the uplinks on the isolated devices? If so, check the underlaying physical links and see if NAV has connected these properly.

What kind of devices are involved in the links that NAV no longer detects topology for? Some HP devices seems to receive CDP messages and present them as LLDP. Also most non-cisco devices can broadcast CDP messages resulting in false topologies being detected in mixed cisco/non-cisco networks.

Are you sure the detected topology NAV presented in the netmap before the upgrade were actually correct? In our office network the topology NAV did present in the netmap before 4.8 were quite full of errors and nobody here had noticed...

Best regards

Sigmund Augdal

On 04. des. 2017 17:17, William Daly - Network Specialist, VUSD Technology wrote:

 

Hello,

 

So I looked at several nodes on both ends. They do show up on either end as a “Candidate neighbor.” However, it does appear that it is using CDP instead of LLDP. Is there a way to force NAV to use LLDP only?

 

Thanks,

Will

From: nav-users-request@uninett.no [mailto:nav-users-request@uninett.no] On Behalf Of Sigmund Augdal
Sent: Monday, December 4, 2017 12:12 AM
To: nav-users@uninett.no
Subject: Re: Netmap

 

Hi,

NAV 4.8 includes various changes to the topology analysis code in NAV. One change cleans up previously deducted topology when ports has been re-used for other purposes. The other fixes some buges where NAV would incorrectly deduce that certain port pairs were connected when they in fact were not, and this in term caused NAV to fail to detect the proper topology. Both of these changes could lead to isolated nodes in cases were NAV is not able to detect the correct topology. In order to resolve these issues it would be very useful to have some information about the topology candidates nav has gathered for the ports in question.

Go to the reports overview and click "Report List" and then "Direct neighborship candidates". Click "Filter" and type the sysname of an isolated node in the sysname field and the name of an uplink port in the interface field and press filter. Does the expected upstream device show up in the list? What is in the "source" column.

Then repeat for the expected port on the upstream device. If you could send us the lists of candidates for both ends it would be of great help to debug.

In order to get the best topology results we recommend using lldp on all topology ports, and to _not_ use CDP in mixed Cisco/HP networks

Best regards
Sigmund Augdal
UNINETT AS


On 01. des. 2017 18:29, William Daly - Network Specialist, VUSD Technology wrote:

Hello,

 

I am also having issues with isolated nodes in netmap. I updated to 4.8.1, and now I have unconnected nodes.

 

From: nav-users-request@uninett.no [mailto:nav-users-request@uninett.no] On Behalf Of Erik Kemper
Sent: Friday, December 1, 2017 2:50 AM
To: nav-users@uninett.no
Subject: RE: Netmap

 

 

Hi,

 

They show up when I select “isolated”  in the view.

But how they got isolated, I cannot figure out?

 

 

Met vriendelijke groet/ Kind regards,

 

Erik Kemper

Senior Datacenter Engineer

 

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Quaker Chemical B.V.  I  Industrieweg 7  I  1422 AH Uithoorn  I  The Netherlands

T: +31 (0)297 544430  I  F: +31 (0)297 544694

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From: nav-users-request@uninett.no [mailto:nav-users-request@uninett.no] On Behalf Of Erik Kemper
Sent: Friday, December 1, 2017 11:25
To: nav-users@uninett.no
Subject: RE: Netmap

 

 

Hi,

 

Okido, will do!

 

(Did not see that HowTo.. 😊)

 

 

Met vriendelijke groet/ Kind regards,

 

Erik Kemper

Senior Datacenter Engineer

 

 

 

Quaker Chemical B.V.  I  Industrieweg 7  I  1422 AH Uithoorn  I  The Netherlands

T: +31 (0)297 544430  I  F: +31 (0)297 544694

kempere@quakerchem.com  I  quakerchem.com

Commercial Register Amsterdam No: 33.109.151  I  VAT no: NL 001277613 B01

 

-----Original Message-----
From: Morten Brekkevold [mailto:morten.brekkevold@uninett.no]
Sent: Friday, December 1, 2017 11:12
To: Erik Kemper <kempere@quakerchem.com>
Cc: nav-users@uninett.no
Subject: Re: Netmap

 

On Fri, 1 Dec 2017 09:46:42 +0000 Erik Kemper <kempere@quakerchem.com> wrote:

 

> Nothing special, just the regular weekly update run?

 

I don't know what "the regular weekly update run" entails, so I still don't know what changed.

 

The minimum amount of information we need to make sense of a problem report is at least the NAV version in use.

 

In your case, I'd suggest reading through [1] and come back with some more detailed information about your system and your symptoms.

 

 

[1] https://nav.uninett.no/doc/howto/debugging-topology.html

 

--

Morten Brekkevold

UNINETT

 

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