Switches, Hubs, and Modems
cancel
Showing results for 
Search instead for 
Did you mean: 

2800 Series Switch and vlan config

SOLVED
Go to solution
Joseph L. Casale
Regular Advisor

2800 Series Switch and vlan config

Hi all,
I have been reading about vlans and have a few questions:

1. If a port is untagged into a vlan, will it strip an existing vlan tag from a 802.1q compliant device if it existed and retag it?

2. Similarly, if a port is tagged onto one vlan and the device is setup for another, I assume the switch will drop the packets?

3. If I had a switch that had GVRP enabled, and I had two vlans that were from a security point of view needing to be isolated reliably, are there any ramifications to having ports untagged in the secure isolated vlan and auto in the default vlan? Does that present a security issue under any possible circumstance?

4. I have a pair of switches in two buildings separated by fiber with a couple of GBIC's trunked in each switch setup using LACP. I also have 5 HP servers with NIC teaming setup in the host and both switch ports they each use are trunked (as the docs a former IT helper suggests). What is the correct config for these two different scenarios, or is this correct? Is it correct to team the NIC's and trunk the two ports on the switch?

Thanks so much!
3 REPLIES
Andrew_291
Frequent Advisor

Re: 2800 Series Switch and vlan config

1.Not so simple 8)) That packets will be rejected by the switch.
2.The same.Port tagged for one vlan can't receive packets assigned to another vlan.
3.Seems to me there is not security issue on that configuration.
4.All your scenarios are correct, be care 8))))
Joseph L. Casale
Regular Advisor

Re: 2800 Series Switch and vlan config

Thanks for the reply Andrew,
So what is the difference between scenario 1 and 2? Just that scenario 1 will allow a non 802.1q device into a vlan where as scenario 2 will require an 802.1q device before it will pass traffic?

Also, scenario 3 with devices in vlan 1 having a vlan2 set as auto isn't there a possibility they could attain membership in vlan2? If it was imperative they not ever be in vlan2, shouldn't it be setup as forbid? Can't the auto status ever untag the traffic into it or worse allow an 802.1q device to tag his traffic into it?

Thanks!
Andrew_291
Frequent Advisor
Solution

Re: 2800 Series Switch and vlan config

--------------------------------------------
So what is the difference between scenario 1 and 2? Just that scenario 1 will allow a non 802.1q device into a vlan where as scenario 2 will require an 802.1q device before it will pass traffic?

--------------------------------------------
There is no diiference between scenario 1 and 2
from point of view any networking device , as simple- it "think" "if I receive packet could not understood by me I reject him anymore".Non-802.1q compilant network device will reject tagged packets and untagged switch port will not send to "switch core" any tagged packet - it just bring it to own "null device"

------------------------------------------
Also, scenario 3 with devices in vlan 1 having a vlan2 set as auto isn't there a possibility they could attain membership in vlan2?
------------------------------------------
No.If that devices configured with VID corresponding to vlan2 - they NEVER WILL BE member of vlan1.And opposite are right - devices configured as members of vlan1 never will be in vlan2 too.





-------------------------------------------

If it was imperative they not ever be in vlan2, shouldn't it be setup as forbid? Can't the auto status ever untag the traffic into it or worse allow an 802.1q device to tag his traffic into it?



------------------------------------------