Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
Announcements

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. If you'd prefer to explore, try our test area to get started. And see here for current known issues.

New Member

Switch connected to hub

Hi all,

if switch port is connected to hub and we have 2 pc connected to hub.

if we do sh mac-address on switch with

MAc- address of each pc will it show same

port for 2 different mac address for pc?

also if user pn pc 1 is sending data to pc 2 how data will go directly via hub only or will it go to hub then to switch

and then to hub and users.

will cam table entries show both pc mac address or hub mac address on the incoming port?

many thanks

3 ACCEPTED SOLUTIONS

Accepted Solutions
Hall of Fame Super Blue

Re: Switch connected to hub

Mahesh

"will it show same

port for 2 different mac address for pc?"

Yes the switch port will show both PC mac-addresses.

A hub sends data out of all ports except the port the data came in on so if PC1 sends data to PC2 then the data will not have to go "via" the switch altho the switch port will also receive the traffic in addtion to PC2.

Jon

Hall of Fame Super Bronze

Re: Switch connected to hub

if we do sh mac-address on switch with

MAc- address of each pc will it show same

port for 2 different mac address for pc?

Yes.

also if user pn pc 1 is sending data to pc 2 how data will go directly via hub only or will it go to hub then to switch

and then to hub and users.

Data will remain in the hub.

will cam table entries show both pc mac address or hub mac address on the incoming port?

Both PCs. Most Hubs have no intelligence (no MAC address).

__

Edison.

Hall of Fame Super Silver

Re: Switch connected to hub

Hello Mahesh,

the sh mac-address-table interf type x/y will show two entries

the switch knowing that both MAC addresses are out the same port will perform MAC address filtering and will not forward frames originated from PC1 and destinated to PC2 to other switch ports in the same Vlan.

For how the hub works each frame is sent out all other ports with the exclusion of the receiving port.

you will never see the hub mac address unless it has a management TCP/IP stack:

the hub is simply an electrical repeater that obliges to work in half duplex for what I write above: it replicates a frame out all other ports

Hope to help

Giuseppe

4 REPLIES
Hall of Fame Super Blue

Re: Switch connected to hub

Mahesh

"will it show same

port for 2 different mac address for pc?"

Yes the switch port will show both PC mac-addresses.

A hub sends data out of all ports except the port the data came in on so if PC1 sends data to PC2 then the data will not have to go "via" the switch altho the switch port will also receive the traffic in addtion to PC2.

Jon

Hall of Fame Super Bronze

Re: Switch connected to hub

if we do sh mac-address on switch with

MAc- address of each pc will it show same

port for 2 different mac address for pc?

Yes.

also if user pn pc 1 is sending data to pc 2 how data will go directly via hub only or will it go to hub then to switch

and then to hub and users.

Data will remain in the hub.

will cam table entries show both pc mac address or hub mac address on the incoming port?

Both PCs. Most Hubs have no intelligence (no MAC address).

__

Edison.

Hall of Fame Super Silver

Re: Switch connected to hub

Hello Mahesh,

the sh mac-address-table interf type x/y will show two entries

the switch knowing that both MAC addresses are out the same port will perform MAC address filtering and will not forward frames originated from PC1 and destinated to PC2 to other switch ports in the same Vlan.

For how the hub works each frame is sent out all other ports with the exclusion of the receiving port.

you will never see the hub mac address unless it has a management TCP/IP stack:

the hub is simply an electrical repeater that obliges to work in half duplex for what I write above: it replicates a frame out all other ports

Hope to help

Giuseppe

New Member

Re: Switch connected to hub

Hi ,

Thanks all for great timely reply to answer my question

Many thanks

Mahesh

190
Views
0
Helpful
4
Replies