Management VLAN - Addressing

[colinkiely1]

Easy one for you chaps, I am sure!

I am going to create a seperate management vlan across all my sites. I was just wondering if I am able to allocate a /32 to the SVI? I am pretty sure this will work, just wanting clarification as cant lab it right now. Also, in my OSPF network I can just advertise 0.0.0.0 mask for each address?

Also, the only real benefit to not SSH'ing into my data vlan remotely would be less traffic?

Thx

[Latchum Naidu]

Hi,

Why you want assign /32 to the SVI?

Any how please find below may help you...

I tested something today on a Layer3 switch which is not a “standard” configuration but it seems it works. Basically you create a loopback interface on the Layer3 switch and configure an IP address on the loopback (lets say 10.10.10.10/32). Then, assume vlan 2 is network subnet 10.2.2.0/24. On the PCs connected on Vlan 2 you can configure as default gateway the switch loopback address (10.10.10.10) and it seems that it works. If you have another vlan 3 with layer 3 subnet 10.3.3.0/24, then you configure again the loopback address (10.10.10.10) as default gateway for the hosts on that vlan. So you have a single IP address as default gateway for all hosts on your vlans.

Again this is NOT a standard scenario

And SSH will generate less traffic as per best practices.

Please rate if this helped you...

Regards,
Naidu.

[colinkiely1]

Naidu

I think you are a little out from what I am asking, but along the same lines. Forget about the gateways etc for the PC's at the moment, and lets assume these are access switches, with no routing enabled. I was just curious if I wanted to use, say, a standard /24 network, and vlsm up the subnet to essentially give me 255 indivual hosts - could I use, for instance

192.168.1.1 255.255.255.255 - SW1 - London

192.168.1.2 255.255.255.255 - SW1 - Rome

192.168.1.3 255.255.255.255 - SW1 - Paris

Similar to loopback but I could use a standard VLAN number, lets say 500, across all my sites. And then telnet/SSH in on that address

Hope this makes sense

[cadet alain]

Hi,

You can't assign a /32 to a SVI

and vlsm up the subnet to essentially give me 255 indivual hosts

you already have 254 hosts in a /24 and vlsm = different subnet masks so it has nothing to do with what you asked.

Why would you use a /32, I don't understand the why.Is it for ospf network command with the 0.0.0.0 mask? This mask enables ospf on the interface with the ip address you put in the command and advertise the subnet it is part of so you don't need a /32 to do that and furthermore you said  in your previous post you had no ip routing.

Regards.

Alain

[colinkiely1]

Ok, forget SVI for a second. Let me call it my managment vlan. Can I assign a /32 to my management vlan interface on an access layer switch?!

OSPF will be running on higher layer switches. I was trying not to complicate the question

[cadet alain]

A VLAN interface = SVI so the answer is still NO .

Regards.

Alain.

[colinkiely1]

Please explain why, as I have been told on other forums this is possible. I will lab it up this morning and let you know the outcome

[cadet alain]

I've labbed it and it was not permitted

.

Regards.

Alain.