"Discover" physical network topology

[kamarale]

Hello,

I need to "discover"/ know the network physical network topology of several HP switches.
We are going to configure VLANs so I need to know all the uplinks between the switches.

I am planning to do it with LLDP connecting to all the switches, but maybe you guys know a better approach.

Thank you in advance.
Regards.

[deanwebb]

Reading the routing table is always helpful, if it has a routing function on it. If these are chained switches, then you'll be looking at possibly a bunch of MAC addresses and IP addresses. The first 6 digits of a MAC address go with the manufacturer, so looking those up online will help you find uplinks because they match on a switch vendor.

HOWEVER, if you have a lot of HP laptops and HP printers in that environment, then that will make sorting out the switches more difficult.

LLDP is good, but you might also find a lot of phones connected to the switch, potentially.

If you can go directly to the switches and follow the cables, then you'll know which ports are used for connections to other switches and then use that port information to look up IPs and MAC addresses on the switch.

[kamarale]

Hello,

Is there a good software you guys know to do this? to "draw" the physical topology/physical uplinks of switches

Thanks!

[deanwebb]

Hello,

Is there a good software you guys know to do this? to "draw" the physical topology/physical uplinks of switches

Thanks!

I've always been in the position where I had to take my discovery and manually transfer it to a Visio document.

[Dieselboy]

Depends on what you are wanting to achieve. You can trace the network via mac addresses. E.g. to find where firewall or routers are connected you can show the mac address tables of the switches and figure out which switch ports are connected to which devices.

LLDP will show you other devices speaking LLDP.

Spanning tree could also help, if it's enabled on the switches.

Lastly do a manual trace and document on paper what connects to where

[kamarale]

Hello,

Yes I will end up doing that.
I never used soft like solarwinds Network Topology Mapper or similars to that. I do not know how well they can discover the topo.

Than you

[deanwebb]

It's important to note that even automated tools need a human re-working, especially if you have duplicate IP address ranges for things like HA links or firewalled mini-sites for manufacturing.

[icecream-guy]

the topology mappers usually use SNMP, so all your devices would need to be configured for SNMP

[dlots]

It's one of my 1st works, but this SSHed to devices  and  builds the database. 
https://github.com/GoreNetwork/Network-Walker
This one will build a network map in yed.
https://github.com/GoreNetwork/Build-Network-Map

These are built for Cisco devices just an FYI