Refer to the following diagram, where a switch with ports 1 to 8 is connected to
ID: 3711031 • Letter: R
Question
Refer to the following diagram, where a switch with ports 1 to 8 is connected to devices with MAC addresses A to H. 1. 7 L-8 1 2 3 4 Port Number Access Point Devices Assume that the forwarding table is initially empty and that the following sequence of transmissions occurs (each is a one-way frame transmission and there is no timeout of Forwarding Table entries during this time) i. Station A transmits a frame to server D ii. Station E transmits a frame to station H iii. Server D transmits a frame to station A iv. Station F transmits a frame to server C rD transmits a fraExplanation / Answer
A.
The above table is formed in the following way:
When a new frame reaches a switch, whose MAC forwarding table is empty, a new entry is made in the table for the source MAC address from where the frame is sent along with its port number through which the switch has received the frame. Upon receiving the frame, the switch will lookup the table for the destination MAC address and its port number. If found it will send the frame through that interface. Or else it will flood the frame to all the ports(interfaces) except the port through which switch received the frame.
B. As mentioned earlier if the entry for destination MAC doesn't exists it will flood out to all interfaces(ports)
i) For frame from A to D
Ports 2,3,4,5,7 and 8 are the ports through which the frame is transmitted out of the switch as a result of flooding
Port 1 is not used for out putting the frame, because it is the port through which frame is received.
ii ) from E to H
Ports 1,2,3,4,7 and 8 are the ports through which the frame is flooded out to all the devices.
iii ) for D to A
Port 1 is used to transmit the frame out to device A, as there is an entry for MAC address A in the MAC forwarding table at switch.
iv ) F to C
Ports 1,2,3,4,7 and 8 are used to transmit the frame out of switch as there is no entry matching C mac address
v) from D to F
Port 5 is used to transmit the frame out of the switch to the destination MAC address F, as there is an entry for MAC address F in the MAC forwarding table.
MAC address Port A 1 E 5 D 4 F 5