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Possible to assign ports across different stackable switches to same trunk group?

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Bill Oyler
Occasional Visitor

Possible to assign ports across different stackable switches to same trunk group?

Hello,

Disclaimer: I come from the Cisco world where I am familiar with the Cisco 3750 stackable switches which use a dedicated 32 or 64 Gbps stacking cable to make the stacked switches operate just like a chassis switch. HP ProCurve "stacking" seems to be a bit different. My question follows:

With an HP stackable switch (such as the ProCurve 3400cl or 3500yl), is it possible to assign ports from two *different* HP switches into the *same* trunk group? For example, let's say I have an EMC Celerra NAS appliance or a NetApp NAS appliance that I want to connect across two switches for high availability and load balancing. In the Cisco world, I would create a single EtherChannel group, perhaps consisting of (2) ports from each of the (2) Cisco 3750 switches, for a total of (4) ports in the EtherChannel connected to the EMC or NetApp. The EtherChannel (or "trunk" as HP calls it) essentially spans two switches (which look like a single switch from the Cisco IOS perspective). The advantage to this approach is that all (4) ports are active at all times, and participating in the src-dst-ip load balancing algorithm, and offer automatic non-disruptive failover in the event of a switch failure.

Is this possible in the HP world with "stackable" ProCurve switches like the 3400cl or 3500yl? Everything I have read on the topic so far is leading me to believe that HP's "stacking" concept doesn't really provide this capability and that a ProCurve "trunk" must begin and terminate across 2 devices only. If this is true, then it doesn't seem like 2 HP switches, regardless of whether they are stacked, could both participate in the same trunk terminating on an EMC or NetApp device.

If this is the case, I am assuming that in order to achieve the high availability and load balancing that I am looking for, I would need to go to a chassis-based switch like the 5400 series, which would allow a trunk to span multiple modules in the chassis.

Is this logic correct, that I can't do "cross-switch trunking" on the ProCurve 3400cl or 3500yl?

Thanks,
Bill
6 REPLIES
RicN
Valued Contributor
Solution

Re: Possible to assign ports across different stackable switches to same trunk group?


Hello Bill,

what you are assuming is correct. The aggregated ports must start and end from single devices, and the closest thing is, as you say, is the module redundance you get from having multiple port modules in the same chassi, like a 5400 or similar.
benjamin_martin
Occasional Visitor

Re: Possible to assign ports across different stackable switches to same trunk group?

While that may have been true in the past, the product overview page for the 3500yl states:

"Server-to-switch distributed trunking: allows a server to connect to two switches with one logical trunk that consists of multiple physical connections; enables load-balancing and increases resiliency New!"


I am also looking to implement this for my 7 node isilon cluster

Re: Possible to assign ports across different stackable switches to same trunk group?

This is one of the features introduced in the K.14 software (currently in Early Availability state): "Distributed Trunking: Allows a server to connect to multiple switches with a single logical trunk enabling load-balancing and redundancy."

Before upgrading to this version please read:
http://www.procurve.com/customercare/support/software/k14.htm

Bill Oyler
Occasional Visitor

Re: Possible to assign ports across different stackable switches to same trunk group?

Thanks for the followup, guys. The new Distributed Trunking feature looks very interesting. From reading the caveats associated with this new feature, it looks like the only "major" problem I see is that IP routing (L3) can't be running on the switches that participate in this new form of trunking. It will be interesting to see if this restriction gets lifted in the future. It will also be interesting to see if this feature works with VMware ESX hosts. I would think it would, but the fact that the manual explicitly says that only "servers" are supported makes me wonder if only certain NIC types or host operating systems are supported.

If anyone has time to play around with this new feature and report on its real-world functionality, I'd be very interested.

Re: Possible to assign ports across different stackable switches to same trunk group?

I very curious aswell to hear if anyone has tried the new "Distributed Trunking" feature.

I'm especially interested in knowing if it is seen by connected devices exactly as a normal LACP trunk to a single switch or if it requires and special support from the connected devices.

I'm also curious about if it works in together with the switch mesh feature. In that case I'd like to create a setup like:

ISP1 ISP2
! !
R1 R1
/ \ / \
S1 -- S2 ----------- S3 -- S4
! !
+---------------------------+

Where:

* R1, R2 are Juniper M7i routers.
* S1-S4 are HP Procurve 3500yl switches.
* R1, S1, S2 is located as site1
* R2, S3, S4 is located as site2

* S1 and S2 are stacked over a normal 2-port LACP trunk.

* S3 and S4 are stacked over a normal 2-port LACP trunk.

* The S1/S2 stack and S3/S4 stack are meshed with a GE link between S1/S3 and one between S2/S4.

Then I should be able to run a LACP trunk to S1/S2 from R1, and the same from R2 to S3/S4.

Create VLANS with VRRP between R1/R2 and tag everything to the L2 stacks and hook up customers redundant and load balanced at each site, or even connected to the same VLAN at both sites.

I'll buy a few 3500yl switches within the next few weeks to start playing with this and report back my progress.
O.H.M
Occasional Visitor

Re: Possible to assign ports across different stackable switches to same trunk group?

Hi all,

I am facing a strange situation.
I have just bought two new 3500yl switches in order to implement the new distributed trunking feature on a SAN network.

Both switchs are linked with 2ports trunk LACP set as the ISC link.

A 2ports LACP trunk is setup from an HP server 380 G4 and linked to both switches, one server port linked to one switch and the other port linked the secondary switch.

The problem is that when linking the ports to the switches, one of the ports become blocked and the other . Hence i suspected the Spanning Tree for blocking LACP trunk, but even after disabling ST. The ports still revert to Blocked state after plugging cables??

Can someone help me on this, that new feature is relatively new and is not largely explained on the web.

Is there someone

--------------------------
Local Port Status:

PORT LACP TRUNK PORT LACP LACP
NUMB ENABLED GROUP STATUS PARTNER STATUS
----- -------- ------- -------- -------- -------
3 Active Trk3 Up Yes Success
4 Active Trk4 Up Yes Success
5 Active Trk5 Up Yes Success
6 Active Trk6 Up Yes Success
25 Active Trk25 Blocked No Failure

Remote Port Status:

PORT LACP TRUNK PORT LACP LACP
NUMB ENABLED GROUP STATUS PARTNER STATUS
---- ------- ------- ------- ------- -------
3 Active Trk3 Down No Success
4 Active Trk4 Down No Success
5 Active Trk5 Down No Success
6 Active Trk6 Down No Success
25 Active Trk25 Up Yes Success