MAC address table in layer 2 switch

[azi123]

Hi,

I have two questions about the way a switch completes its MAC address table:

1. Suppose host A starts sending  packets for host B through a switch ( destination MAC addresses of packets are host B MAC address) and there is no response from host B to host A ( see the attachment please), I mean there is no ARP or CDP or similar protocols and host A just send layer 2 packets to the switch ( leaving higher layer headers empty ) . Does the switch "learn" to put host A packets on correct port for sending to host B or it will keep flooding them? 

2. Is this scenario ( question number one scenario)  possible in a real and practical network? I mean that is it possible that no ARP or ARP-like protocols exists in a network and all the packets don't have any acknowledgment ( i.e. UDP)  to help L2 switches learn destination MAC addresses and stop flooding packets?

Best,
Amir

[rais]

If a switch doesn't know where MAC-B resides, it will keep flooding the packet. This is how all switches work. Practically, there are so many apps on a host, that the switch will learn the MAC. It's however possible that a device never has to send any packet out.

HTH.

[sivam siva]

As rais said Switch floods the frames if destination MAC is unknown,but it will flood the frames only on the same broadcast domain (same VLAN and Trunk ),

switch will learn the MAC from frames source MAC address when it receives first packet,whereas your second question answer is yes ,its depend upon the machine and running config.