VLAN Routing

[todd.waltman]

If packets need to travel from VLAN1 to VLAN2, do the packets move through the sub-interface on the router or does the router just tell the switch where to send the packets?

[dhavaltandel]

hello

here you are asking for inter vlan routing.

as router has physically one interface only the packet come to each sub-interface does routing between eachother as router has information of both the subnet.

additionally it is the same physical interface so need not to configure any routing...

regards

dhaval tandel

[todd.waltman]

Sorry. I don't quite understand your answer. Let me clarify. I have one switch, one router with one physical interface and two subinterfaces, and two subnets (two VLANS). If host 192.168.0.10 wants to access data on host 192.168.5.10, do packets move through the sub-interfaces or does the router simply tell the switch where to send the packets?

[Collin Clark]

Todd, they go through the sub-interfaces.

[kamlesh.sharma]

both the things are possible.

1. is simple and normally used in the network inter-VLAN.

2- called MLS multilayer switching where for every destination first packet goes to router and switch stores the computed information n the MLS catch. than all subsequent packet will be swithed from switch only as it knows how to forward the packet.

For your information any packet going to different network it needs a gateway mac address than gateway router removes source MAC address to it's own interface mac address for the destination network.

say for example you have a switch and a router like this

R1====|sw1|--H1(MAC1)

|

H2(MAC2)

R1 has one mac address on the interface MAC-R1 so for data first time going from H1 will be like this.

1. Source MAC destination MAC

MAC2 MAC-R1

router than will send it to host 2 after manupulation like this

2. Source MAC destination MAC

MAC-R1 MAC1

Till now switch was switching packets between individual mac addresss but now in 3d step it will work one step further. like this.

1. Source MAC destination MAC

MAC2 MAC-R1

2. switch will forward it like this.

source MAC destination MAC

MAC-R1 MAC1

Thanks

kamlesh