Superstack 4924 Vlan

[jonas21]

Hi,

i've got a question regarding vlans on the 4924.
This is the problem:

We have a Cisco router, which connects via GigE to the 4924.
The 4924 acts as a Coreswitch, connecting serveral smaller Cisco 2950 switches which connect the clients.
Our current problem is, that there are alot of broadcasts going through the entire network.

We are thinking of setting up a vlan for each Client Cisco2950.

E.g.:
4924 Port 1 = Cisco router Uplink
4924 Port 2 = Connected to Cisco 2950 #1
4924 Port 2 = Connected to Cisco 2950 #2

So, right now i would create these vlans:
Vlan1 has member ports 1 (uplink) and 2 (client).
Vlan2 has mamber ports 1 (uplink) and 3 (client).

Is this
a) possible
b) will this stop the broadcasts?
(I dont care if vlan1 routes over the cisco if it wants to connect to vlan2).

According to 3com this should be possible with normal untagged vlans without routing (by the 4924).


Jonas

 

[jonas21]

Sorry,

it should read:
4924 Port 1 = Cisco router Uplink
4924 Port 2 = Connected to Cisco 2950 #1
4924 Port 3 = Connected to Cisco 2950 #2
^^^^^

Jonas

 

[TimRegester]

You should find out what the broadcasts are first, before you plan to VLAN your network.

Do some network analysis at several points in your network. If you can remove the broadcasts at source you might not need to change your network at all. I would get ethereal or some trial network analysis software and do a sniff off each switch.

Sure it will create a number of broadcast domains if you VLAN your network but it will not remove the broadcasts merely segment them.

If you have one VLAN per switch the 4924 can do simple layer 3 routing anyway thus removing dependency on the cisco router as a form of one armed router, this would be eminently more sensible.

Port based VLANs with one switch per VLAN will work well.

btw all ports are in VLAN 1 on 3Com and cisco for management puproses, so use VLAN 2 onwards for your new VLANs and a seperate VLAN for your router connection.