Management Networks

[Basher]

Hi guys,

I realise the importance of networks to manage a networks devices, but am not as fully clued up on how these should be implemented. What does a management vlan offer than management subnets do not, and how does combining a management subnet and vlan help/what does it offer to businesses?

Any help would be great

Regards,

James

[jamin]

Hi dude,

Not quite sure what you are asking mate. Are you talking about SNMP network management? Can you give examples?

Don't confuse subnets and Vlans they really are 2 seperate entities, with very different modes of operation. It would be possible essentialy to migrate from one to the other but without knowing how they were implimented any answer I could give would be vague at best.

Jamin

[Basher]

Ok imagine you have a network in a data center and you want the traffic for production systems and traffic for network management, so, SNMP, KVMoIP, iLO, that sort of stuff seperate. I can see two options here, two vlans on a switch, one for production, one for management, or two subnets for the same purpose. What would one offer over the other? Do they not both reduce the broadcast domain or does one offer more/less than the other?

Regards,

James

[atrull]

sounds like he's doing a question for uni or an interview

management networks offer security separation from user networks, dmz, and external networks.. you don't want to expose your system/device management interfaces on your network devices to too many users (especialy not ones from outside your organisation) but you do want to give your admins access, so you stick your admins workstations and your network devices management interfaces on the management network and the admins do their job.. as opposed to sticking admins, users and management interfaces on the user network, dmz network or whatever network.

[atrull]

typicaly a NOC is on the management network, as are all the management interfaces of the network kit / servers.

[Basher]

Yeah cheers, i have lots of info and fully understand why management networks are so important, but understand less the difference between subnetting it and vlaning it, could you shed any light on that?

Thanks for the help,

James

[atrull]

stick ILO interfaces on a separate OOB network (out of band) - as well as any out of band serial switches for when your management network goes down. ssh to the serial switch, pick your serial port and you have a local serial console to your network devices..

[atrull]

subnetting and vlanning are segmentation at layer 3 and layer 2 respectively.

vlans divide up switches into logical partitions (even across multiple switches if you trunk them etc), subnetting divides up networks into logical partitions...

you realise google will help you find definitions..

[Basher]

Yeah i realise they divide at different layers, but surely they both divide up into logical segments to decrease the broadcast domain?

I'm thinking the main reason to choose VLAN is that cisco devices listen on the management vlan which is, by default 1. If production traffic is not vlan'd it will also be using vlan 1 so the switch will have to process all of that unneccessery traffic. Soooo either production or management will have to have a seperate VLAN to avoid this, and obviously doing it to management will be much more straight forward.

Cheers,

James

[atrull]

I'd just manage the vlans better if I were you decide on a production network range and subnet number, configure the switch ports, migrate things over..

[Basher]

Cheers for the help

[Basher]

Yeah i realise they divide at different layers, but surely they both divide up into logical segments to decrease the broadcast domain?

I'm thinking the main reason to choose VLAN is that cisco devices listen on the management vlan which is, by default 1. If production traffic is not vlan'd it will also be using vlan 1 so the switch will have to process all of that unneccessery traffic. Soooo either production or management will have to have a seperate VLAN to avoid this, and obviously doing it to management will be much more straight forward.

Cheers,

James

Could someone in the know confirm that this is the case?

Cheers,

James