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New Member

How to make switch work as a hub?

I have a L3 Switch. As per my project requirement, I want this switch to work as a hub...i.e a port copies all its data to all other ports.

We do not have hub in our premises, hence we are keen to do this.

Please help!!

7 REPLIES
New Member

How to make switch work as a hub?

I guess its like this

interface range fa1/0 - 24

bridge-group 1

exit

bridge 1 protocol ieee

and you will have all interfaces in bridge mode and my guess is that if this doesn't work there is not another way to do it unless you flood the cam talbe until it reaches it maximun memmory and the switch will start working as a hub.

mac-address-table aging-time 1000000 ! and start sending traffic with tons of different source mac addresses

cheers

New Member

How to make switch work as a hub?

I think adding all the interfaces to the same bridge-group would turn the switch into something hub-like, *if* you also create an individual SVI for each of the switchports.

That way, there is a separate MAC address table for each port, with no MAC addresses in them for any devices on other ports, so all traffic ends up being "broadcasted" out of each SVI onto the bridge-group, thus being received by all other SVIs and hence physical ports.

Not that I've ever tried it.

Cisco Employee

How to make switch work as a hub?

Matthew,

I do not think that the bridge-group access is a viable approach at all, because of several reasons:

  • Between multiple member ports in a bridge-group, the traffic is switched, not flooded.
  • Ports in different bridge-groups can not communicate at all.
  • SVIs (i.e. interface Vlan) are not related to bridge-groups in general;  BVIs (i.e. interface BVI) do not need to be created for a bridge-group, and even if they are, they handle Layer3 functions and do not influence the bridging
  • With particular respect to Catalyst switches and bridge-groups, the SVIs are relevant because the bridge-group functionality on Catalysts can be configured only over Layer3 routed ports and SVIs. However, this feature is called Fallback Bridging, applies only to non-IP traffic, and operates based on switching, not flooding (see the first two points).

Best regards,

Peter

VIP Purple

How to make switch work as a hub?

What do you want to achieve? I don't see a single reason why you would want to do that.

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Don't stop after you've improved your network! Improve the world by lending money to the working poor: http://www.kiva.org/invitedby/karsteni

Re: How to make switch work as a hub?

Hello

I guess the best way is disable its L3 capabilities and use all its port in its default vlan 1( which by default they are assigned already)

Int vlan 1
No shut
No ip address

No ip default-gateway
No ip routing


Int ran xx0/1 -24
Switchport host
Switchport access vlan 1
No shut







Sent from Cisco Technical Support iPad App

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Cisco Employee

How to make switch work as a hub?

Hi,

Deactivating the MAC address learning in the VLAN in which you want the flooding to occur should do the trick: use the following command for the VLAN X in the global configuration mode:

no mac address-table learning vlan X

I am sure you know that degrading a switch to a hub-like operation means losing one of the major advantages of having a switch altogether.

Best regards,

Peter

Bronze

How to make switch work as a hub?

Hi,

Here is a nice idea from Petr Lapukhov, it's applicable to any switch that supports RSPAN functionality

http://blog.ine.com/2008/02/05/turning-switch-into-hub/

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