Switch connected to hub

Answered Question
Feb 25th, 2009
User Badges:

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

Correct Answer by Giuseppe Larosa about 8 years 2 months ago

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


Correct Answer by Edison Ortiz about 8 years 2 months ago

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.

Correct Answer by Jon Marshall about 8 years 2 months ago

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

  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 5 (3 ratings)
Loading.
Correct Answer
Jon Marshall Wed, 02/25/2009 - 07:33
User Badges:
  • Super Blue, 32500 points or more
  • Hall of Fame,

    Founding Member

  • Cisco Designated VIP,

    2017 LAN, WAN

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

Correct Answer
Edison Ortiz Wed, 02/25/2009 - 07:34
User Badges:
  • Super Bronze, 10000 points or more
  • Hall of Fame,

    Founding Member

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.

Correct Answer
Giuseppe Larosa Wed, 02/25/2009 - 07:36
User Badges:
  • Super Silver, 17500 points or more
  • Hall of Fame,

    Founding Member

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


mahesh18 Wed, 02/25/2009 - 07:57
User Badges:

Hi ,


Thanks all for great timely reply to answer my question


Many thanks


Mahesh

Actions

This Discussion