Source Mac/IP -> Destination Mac/IP ?
genXrcist
Member Posts: 531
in CCNA & CCENT
This is a fairly basic concept but I want to be sure of it because my hunch is there will be a question on this on my exam(640-802) this coming Friday.
Host A IP - 192.168.1.10
Host A Mac - 00:01:AE:34:F8:B0
Switch 1 Mac - 00:02:AE:34:F8:B0
Router 1 IP (Fa0/0)- 192.168.1.1
Router 1 Mac - 00:03:AE:34:F8:B0
Router 1 IP (S0/1)- 192.168.2.1
Router 1 Mac - 00:04:AE:34:F8:B0
Router 2 IP(S0/1) - 192.168.2.2
Router 2 Mac - 00:05:AE:34:F8:B0
Router 2 IP (Fa0/0)- 192.168.3.1
Router 2 Mac - 00:06:AE:34:F8:B0
Switch 2 Mac - 00:07:AE:34:F8:B0
Host B IP - 192.168.3.10
Host B Mac - 00:08:AE:34:F8:B0
If Host A pings Host B and has to go through 1 Switch, 2 Routers seperated by a WAN link and finally one more Switch, what are the Destination Mac/IP address as they arrive @ Host B AND what are the returned Source Mac/IP address as they arrive @ Host A?
My Answer/Attempt:
Since Mac address's are always local it's easy to fill in those blanks with the Mac addresses of the last Router along the path to the Host. As for the IP's, since they reside at the Network layer they simply remain intact while the routers are stripping/replacing frames along the route. So the IP should always be the destination IP of the packet, right?
IP Arrival @ Host B: 192.168.3.10
Mac Arrival @ Host B: 00:06:AE:34:F8:B0
IP Arrival upon return to Host A: 192.168.1.10
Mac Arrival upon return to Host A: 00:03:AE:34:F8:B0
I want to be clear that the Mac addresses of the switches do not come into play, correct? The switches simply track the Mac's in their mac-address tables and forward them through the correct port and unless they are tagging them for VLAN routing, they wil not make any changes, correct?
Host A IP - 192.168.1.10
Host A Mac - 00:01:AE:34:F8:B0
Switch 1 Mac - 00:02:AE:34:F8:B0
Router 1 IP (Fa0/0)- 192.168.1.1
Router 1 Mac - 00:03:AE:34:F8:B0
Router 1 IP (S0/1)- 192.168.2.1
Router 1 Mac - 00:04:AE:34:F8:B0
Router 2 IP(S0/1) - 192.168.2.2
Router 2 Mac - 00:05:AE:34:F8:B0
Router 2 IP (Fa0/0)- 192.168.3.1
Router 2 Mac - 00:06:AE:34:F8:B0
Switch 2 Mac - 00:07:AE:34:F8:B0
Host B IP - 192.168.3.10
Host B Mac - 00:08:AE:34:F8:B0
If Host A pings Host B and has to go through 1 Switch, 2 Routers seperated by a WAN link and finally one more Switch, what are the Destination Mac/IP address as they arrive @ Host B AND what are the returned Source Mac/IP address as they arrive @ Host A?
My Answer/Attempt:
Since Mac address's are always local it's easy to fill in those blanks with the Mac addresses of the last Router along the path to the Host. As for the IP's, since they reside at the Network layer they simply remain intact while the routers are stripping/replacing frames along the route. So the IP should always be the destination IP of the packet, right?
IP Arrival @ Host B: 192.168.3.10
Mac Arrival @ Host B: 00:06:AE:34:F8:B0
IP Arrival upon return to Host A: 192.168.1.10
Mac Arrival upon return to Host A: 00:03:AE:34:F8:B0
I want to be clear that the Mac addresses of the switches do not come into play, correct? The switches simply track the Mac's in their mac-address tables and forward them through the correct port and unless they are tagging them for VLAN routing, they wil not make any changes, correct?
1) CCNP Goal: by August 2012
Comments
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kalebksp
Member Posts: 1,033 ■■■■■□□□□□
That is correct, in the case of VLANs the switch inserts a tag with the VLAN information, it still doesn't modify the MAC addresses. -
boostinbadger
Member Posts: 256
Right. The only time the MAC will change is when it enters a L3 device. -
genXrcist
Member Posts: 531
Got it, Thanks guys! I was worried about that one for some reason. And thanks for the 'rule of thumb' when it comes to Mac addy's & layer 3 devices.
1) CCNP Goal: by August 2012