Comware

Hi, I have inherited an AV project with a network with a mix of switches of various types including a couple of HP V1910 JE005A 16P units.

I would like to set up some VLANS on the units.  At the moment the LAN has 2 subnets assigned for products on the AV system, 192.168.22.x and 23.x, with a subnet mask of 255.255.252.0.

I have been told that there are no other subnets at this level available for the kit.

I am wondering if it is possible to set up some VLANS using lower level class c subnets - for example 255.255.255.240.  This would give me a range of 16 devices (including the LAN id and broadcast address).

I have tried this on one of the units but had limited success, as follows:

I set the switch up with it's main IP as 192.168.23.1/255.255.252.0.

It routes to 192.168.20.1/255.255.252.0 for internet access.

I set up a 0.0.0.0 static route.  With a laptop with and IP/subnet/GW of 192.168.23.140/255.255.252.0/192.168.23.1 I could see devices on the switch and the internet.

I set up  a VLAN (ID 113) with ports 1 & 14 as tagged ports.  This makes them hybrid as they still are in VLAN 1

I setup a VLAN interface with the following info: 192.168.23.133/255.255.255.240

I can ping 192.168.23.1 no problem from a device with IP address 192.168.23.148/255.255.252.0.  Pinging 192.168.23.113 fails.

If I then make ports 1 & 14 as in VLAN 113 only (take them out of VLAN1) and  tf I have two devices, IP addresses 192.168.23.114 & 115, both with 192.168.23.113 and 255.255.255.240 gateways and masks they can ping 192.168.23.1 OK but cannot see each other or ping 192.168.23.113.

My routing table looks like this:

0.0.0.0 0.0.0.0 Static 60 192.168.20.1 Vlan-interface1
127.0.0.0 255.0.0.0 Direct 0 127.0.0.1 InLoopBack0
127.0.0.1 255.255.255.255 Direct 0 127.0.0.1 InLoopBack0
192.168.20.0 255.255.252.0 Direct 0 192.168.23.1 Vlan-interface1
192.168.23.1 255.255.255.255 Direct 0 127.0.0.1 InLoopBack0
192.168.23.112 255.255.255.240 Direct 0 192.168.23.113 Vlan-interface113
192.168.23.113 255.255.255.255 Direct 0 127.0.0.1 InLoopBack0

I am fairly new to VLANS etc. so flying by the seat of my pants a bit.

Any advice would be most appreciated.

 Many thanks in advance,

jez

If you have addressed the switch with 192.168.23.1/255.255.252.0., this means you are using the subnet:

192.168.20.0/22.

This comprises the IP addresses:

192.168.20.1-->192.168.23.254

If you want a new VLAN, you need a different subnet to put on it.

The IP address: 192.168.23.133/255.255.255.240

is an address contained within the subnet you have already established, so you can't configure this as a separate subnet on your switch, using a different VLAN.

(Hosts in your original VLAN, when trying to communicate with 192.168.23.133 compare that address with their own IP address/subnet mask, see that it is an address within their own subnet, and try to find it using an ARP broadcast. The host with 192.168.23.133 on it is in a different broadcast segment, so it doesn't see the ARP request, so the host trying to find it gets no response, so you have no connectivity).

-------

If I understand what you are saying, then what you really want is to break up the 192.168.20.0/22 subnet into smaller components.

If you want 2 VLANs, you can use:

VLAN1 - 192.168.20.0/23 (192.168.20.1-->192.168.21.254)

VLAN2 - 192.168.22.0/23 (192.168.22.1-->192.168.23.254)

If you want 4 VLANs, you would use:

VLAN1 - 192.168.20.0/24 (192.168.20.1-->192.168.20.254)

VLAN2 - 192.168.21.0/24 (192.168.21.1-->192.168.21.254)

VLAN3 - 192.168.22.0/24 (192.168.22.1-->192.168.22.254)

VLAN4 - 192.168.23.0/24 (192.168.23.1-->192.168.23.254)

If you want 8 VLANs, you would use:

VLAN1 - 192.168.20.0/25 (192.168.20.1-->192.168.20.126)

VLAN2 - 192.168.20.128/25 (192.168.20.129-->192.168.20.254)

VLAN3 - 192.168.21.0/25 (192.168.21.1-->192.168.21.126)

VLAN4 - 192.168.21.128/25 (192.168.21.129-->192.168.21.254)

VLAN5 - 192.168.22.0/25 (192.168.22.1-->192.168.22.126)

VLAN6 - 192.168.22.128/25 (192.168.22.129-->192.168.22.254)

VLAN7 - 192.168.23.0/25 (192.168.23.1-->192.168.23.126)

VLAN8 - 192.168.23.128/25 (192.168.23.129-->192.168.23.254)

If you want 16 VLANs, you would use:

VLAN1 - 192.168.20.0/26 (192.168.20.1-->192.168.20.62)

VLAN2 - 192.168.20.64/26 (192.168.20.65-->192.168.20.126)

VLAN3 - 192.168.20.128/26 (192.168.20.129-->192.168.20.190)

VLAN4 - 192.168.20.192/26 (192.168.20.193-->192.168.20.254)

VLAN5 - 192.168.21.0/26 (192.168.21.1-->192.168.21.62)

etc...

Thanks Vince.  That makes sense.

I only have control over the 22.x and 23.x subnets but I guess that does not preclude me from subnetting to get the best number of hosts per vlan.

For example...  if I want to have 32 hosts per VLAN and I am using 23.x then I could set the switch up as follows:

Switch address - 192.168.23.1 / 255.255.255.224 (ie. /27)

VLAN 1 - 192.168.23.33 / 255.255.255.224

VLAN 2 - 192.168.23.65 / 255.255.255.224

A VLAN1 host would be 192.168.23.34 - 62 / 255.255.255.224 with a GW of 192.168.23.33

Assuming my understanding is correct then I will give that a go.

Thanks for the help so far - I will post my progress.

So I have made some progress...

I have got a VLAN going with on the range from 192.168.23.160 with a /27 (255.255.255.224) mask.

I have a few questions now....

1 - how do I route traffic between vlans?

2 - I cannot get to the internet unless the host has a mask of 255.255.252.0.  I think this may be the firewall.

3 - I want to route TCP traffic to/from the 22.x subnet.  The kit on the vlan I am setting up sends alot of broadcast messages on UDP which I just want to keep in the VLAN.  I have kit on other switches that needs to talk over IP (telnet) to the kit on 22.160/27 subnet/vlan.  How do I best configure this routing?

Thanks in advance for any help.  I know this is probably pretty basic stuff!

1. The switch will route between any subnets that it has an IP address in.
The hosts need to use the address that's on the 1910 as their "default GW".
(You need to configure each switchport to be in the correct VLAN (untagged) for their subnet. If you have multiple switches, you need to trunk the VLANs (tagged) between switches).

2. The 1910 needs a default route pointing at the internet router.

Sounds to me like your hosts are on the wrong VLANs.

3. See 1.

I just did a google and this is the kind of diagram that I think explains how you use VLANs:

http://help.mysonicwall.com/sw/eng/405/ui2/24000/images/vlan_deploy_diagram-2.jpg

Each colour is a broadcast segment - different colours can't see each other's Layer2 traffic.
To talk among themselves, different colours have to go up to Layer3 and get routed.

To put a host in a colour, you need to assign its switchport to the VLAN and give it a correct IP address for that VLAN.

Or at a simpler level:

http://4.bp.blogspot.com/-dqkJDCAudOM/UbSrLnQOF6I/AAAAAAAABTY/Xf0SXX6qDxg/s1600/3.png