vlan ip adress

[Lovedeep Marwah]

Hi,

if the switch receives apacket on vlan 1 with ip address 192.168.4.253 and if the switch itself is configured with ip address 172.16.24.224 for vlan 1.

is the switch going to accept the packet or its going to drop it?

[Harish Balakrishnan]

hello Lovedeep

can you  tell me the  scenario .. what i understood is if a switch with an IP of 172.16.24.224 on its vlan1 and receives a packet from 192.168.4.253..

if that is the question.. switch will process it if there is no filtering for this IP configred

regards

harish.

[Karsten Iwen]

To drop the packet would be the wrong term. The control-plane of the switch will ignore the packet. The rest will depend on other factors. So for L2-operation the frame could still be forwarded to other destinations based on the MAC-address. For L3-operation the packet can be routed to the destination.

[Lovedeep Marwah]

@harish:how is this going to process is it going to put the packet on native vlan.

the scenario is there is switch A which has an ip 192.168.4.0 255.255.255.0 for vlan 1 and switch B has an ip 172.16.24.234 255.255.255.0 for vlan 1 both the switches have trunk native vlan 10. both the switches have trunlk link connecting through so when i ping 192.168.4.253 from switch A the how is switch B going to process it.

[Harish Balakrishnan]

Hello Lovedeep,

The scenario wasnt clear..

ok in this sitation, Swtich B gets this frame ( ARP request) but it will ignore that since there is no L3 interface with that IP address

regards

Harish.

[Lovedeep Marwah]

hi harish,

I really appreciate your help but this is in production environment and its quite big and messy scenario so i cant give you the clear picture. see if you can get this there are switch A and C they both have there vlan 1 on 192.168.4.0 255.255.255.0 subnet and 192.168.4.253 is connected to switch C . so now switch A can ping 192.168.4.253. if now

i deploy a new switch say switch B between A and C and switch B has vlan 1 on ip 172.16.24.234 255.255.255.0.so the scenario is now a--->b--->c--->192.168.4.253. is it possible for switch A to still ping 192.168.4.253? how switch B will process this ping packets?

Thanks

[Jon Marshall]

Yes you should be able to ping from A to C.

When switch A pings switch C the destination mac-address will be the mac-address of the switch C vlan 1 interface. So switch B will simply look at the mac-address, see that this mac-address can be reached via the connection to switch C and forward the packet onto switch C. When switch C receives the packet it will see the mac-address is for it's vlan 1 interface.

The return ping packet will also work the same way.

Jon