can host insame subnet with different vlans to ping others witout router ?

[Dr.X]

hi ,

ihave a question ,

basic onfigure below ,

can hosts ping others ??

regards

[Dr.X]

but im wondering , if the link between swiches was put in vlan 30. as an example .

i think in this case ,pcs cant ping others

am i right ?

regards

[milan.kulik]

Yes,

you are right.

In your example assigning port Gi 0/1 to VLAN 30 would prevent the PCs to Ping each other.

BR,

Milan

[Dr.X]

thnkx

[rezzaque]

Hi CSCO,

You have the answer above. Anyway let me try to explain you:

In your scenario you have two switches: Switch A----- Switch B & they are connected through Access port. 

( NOTE: Access port doesnt carry vlan information accross the switches.)

So when you have the same network across different vlan between switches you will be able to ping each other.

How????

Lets connect another pc  name C in the switch 1 in f0/5 port with vlan 50 and same segment ip lets 10.10.10.30 . As per your logic a should get ping C or B should get ping to A .. but dont ....

why???

[jain.manish94]

please can someone tell me. 

LAG - Link Aggregation

in Wireless lan controller. 

Why ? 

Benefits ? 

[nspasov]

Hi Jain- I would recommend that you start a new thread under the "Wireless - Mobility" section. That way you will get more visibility to your question with the experts in that field. 

To answer your question: Link Aggregation and Port-Channeling has several benefits. Take a look at the following link:

https://supportforums.cisco.com/document/81681/lag-link-aggregation

Thank you for rating helpful posts!

[jain.manish94]

but by defaults all are  ports in vlan 1 

[jain.manish94]

Hi Pulikkar 

please can you clear it how can they ping each other because trunk is not enable. and ports are in different vlan. without trunking how they can carry traffic...

[milan.kulik]

Hi,

if you look at the config for ports Gi0/1, they are configured as access ports on both switches.

So the Ethernet frames are sent untagged out of them, no VLAN info is available to the other switch.

So from the SW_A point of view the HOST_2 belongs to VLAN2 and from SW_B point of view HOST_1 belongs to VLAN 5. And the Ping packets are sent from HOST_1 to HOST_2 with no problem.

In fact, there is one big common VLAN 2/5 created by connecting the port Gi0/1 (access port in VLAN 2 on SW_A) to the other Gi0/1 (access port in VLAN 5 on SW_B).

Am I clear here?

Best regards,

Milan

[jain.manish94]

Hello 

i thing it is not possible did you do any practical for this . without intervlan routing they can not communicate to each other .... in this case what is the benefits to create vlan , and why we assing hosts in diff-2 vlans. 

because when pc1 send ping to pc2 switch one will check packets but with vlan info becuase pc1 port is in vlan 2 but pc2 port is in vlan5 , in that case switch two will not accept vlan 1 info and drop it. 

[milan.kulik]

Hi,

it is possible, I've seen this bad LAN design several times.

You are right it makes no sense to interconnect two VLANs by access ports - you are creating one common VLAN then.

I've seen only twice in my life a situation when it made a good sense to go this way.

But if done, you can see:

As the switches are NOT connected via a trunk, switch_A does NOT know PC2 is in VLAN 5 on the OTHER switch.

All he knows is: The PC2 MAC address is visible on port Gi0/1 which belongs to VLAN2 as well as the port to which PC1 is connected to!

So from his point of view both PCs are in the same VLAN!!

If you don't trust me, build a lab and you will see it works this way...

Best regards,

Milan

[jain.manish94]

yes milan , definitely i will try first . then i can believe on it.

why the way where are you from in which company you are working. actually i have some question where i am facing some problem....

1 one is in NCM solar winds.

2. discarded outbond packets from one port.

[pwwiddicombe]

If you check the logs on the 2 switches, you will probably see that the switches will be complaining about mismatched VLAN (If CDP is enabled)- but still be functioning. 

(Unless you have some really old switches, like 2924 or 3548 vintage).

[milan.kulik]

Hi,

you can get rid off these annoying syslog messages by disabling CDP on the interconnecting ports or by setting CDP to ver. 1 on them.

Best regards,

Milan

[jain.manish94]

but milan this one is not good for network to disable CDP