Layer 2 VLAN vs. Layer 3 "tagged" VLAN?

[daFranze]

I'm not sure if this is possible, L3 VLANs is quite new to me, so this question might be stupid but please bare with me... ;-)

My company is designing our new Linux Clusters. The boundary conditions are:
RedHat RHEL 5.5
Veritas Cluster VCS5.1

some of the HW requirements are:
* 2 NICs for redundant heartbeat between nodes(which is LLT - low latency transport protocol)
* 2 NICs for redundant "public" LAN (IP Net) - we intend to use channel bonding
* 2 HBAs for redundant SAN access

If you have a HP C-Class half height blade this means you need to use the 2 onboard NICs and add a mezzanine card both for LAN and for SAN. There would be no mezzanine port left for future needs (whatever this might be).

Our Networking guys suggested to use tagged VLANs, but VCS' LLT Protocol is not IP based, so using a "tagged VLAN" for the "public" LAN and a Layer 2 Protocol on the same NIC won't work in a default tagged VLAN configuration.

Is there any way to - well how would you say - create a Level 2 Layer NIC (or something a protocol stack would accept as a "NIC") out of a Level 3 tagged VLAN? Something like a tunnel...

Your help, even if it is a "NO WAY!" is very appreciated.

Best Regards, Franz
--
System Manager (Solaris, HP-UX, Linux, some networking, some SAN)

 

[daFranze]

no ideas, no comments?

Best Regards, Franz
--
System Manager (Solaris, HP-UX, Linux, some networking, some SAN)

 

[ady2012]

My networking knowledges :
If Layer 3 switches able to do routing.Layer 2 hubs unable to do routing.

 

[exsnafu]

so i've never done this in linux and i might be misunderstanding your question but here's the way i read it:

your network guy is suggesting that you run the LLT/GAB VLAN traffic over the same physical NIC for production traffic. basically doubling up those ports. not a bad idea since LLT/GAB is low utilization. you'd still have two physical NIC's for redundancy but they'd be dual purposed.

we do this in AIX(but not for VCS per se) and the way it works is pretty simple, the network team gives us a port on the switch in trunk mode and tags the VLAN's we're going to use to that physical port.

then, in AIX I create virtual adapters for each VLAN I want to have an interface on.. so i end up with something like en0 is the physical adapter and then en1 might be for VLAN10 and en2 might be for VLAN20 etc.

is this not what he's suggesting? at this point you're all layer 2, i wouldn't have any idea what a layer3 vlan is.

googling for "linux vlan tagged adapters" came up with a few howto's that makes it look pretty easy to do.. you end up with ifcfg-ethX.VLANID config scripts...

 

[daFranze]

dear exsnafu,

>> howto's that makes it look pretty easy to do.. you end up with ifcfg-ethX.VLANID config

well, I used these howtos to configure VLANs.
I configured a bond0.305 (channelbonding over eth0 and eth1; I configured the "LAN" Network in this bond), and eth0.315 and eth1.316 for heartbeat.

When I run Veritas Cluster install script it detects two interfaces as suggested heartbeat interfaces using a strange notification: eth0.315@eth0 (as far as I remember)
When VCS runs it's LLT test on these interfaces it fails.

Well, I think we'd bite the bullet and buy mor NICs or use some proprietary network equipment from hp (called Flex-10)



Best Regards, Franz
--
System Manager (Solaris, HP-UX, Linux, some networking, some SAN)