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HP Trunking\Redundancy\2x Core's.

Karl Collinson
Frequent Advisor

HP Trunking\Redundancy\2x Core's.

Morning\Afternoon,
Trying to build in some redundancy.

The design has been done on the cheap, I have 7x 24 Port PoE 2626's as edge switch's supplying X amount of Class 3 PoE Devices.

All 7 switches are going to act as edge switches with 2x Trunked ports on each going to another 1x 2626 (Core) “Each uplink has 2 pairs Trunked as the uplink”

Now I would like to add another 2626 to act as a secondary Core for redundancy.

Can I take a Trunk from an Edge switch and split the connection between the two cores?
So if one Core switch fails the Trunk loses only one of the pair and the connection stays up?

Stacking??

Thanks,
Karl.
7 REPLIES
Igor Ybema
Advisor

Re: HP Trunking\Redundancy\2x Core's.

Yes you can. I don't think this is really supported by HP but it works.
Keep the trunk configured on each edge and connect each one to a different core. You don't have to use a trunk setting on the core switch (as only 1 connection is coming from each edge).
Do NOT connect the cores directly, this will end up in a loop.
Do NOT connect hosts/servers to the CORE (so only to the edge switches). This will result in bad connection to these hosts.
You MUST configure trunk on each edge switch on both ports connected to the core-switches. You will see loops if you don't.

So the core is only for distribution to the edge switches.

In fact,.. this is the last measure which the dutch AMS-IX (www.ams-ix.net) can take if traffic keeps growing but there vendor (foundry in this case) can't keep up with faster/bigger switches. They are now using the second core switch in active/passive failover. But in the situation described here they can use active/active (but don't have a failover in case of software issues anymore).

Igor Ybema
Advisor

Re: HP Trunking\Redundancy\2x Core's.

btw, with 'Do NOT connect the cores directly, this will end up in a loop.', I mean do not connect both cores to each other.
Karl Collinson
Frequent Advisor

Re: HP Trunking\Redundancy\2x Core's.

Morning,
Thanks for your Help.

Already fully aware of the loop issue.
I need the cores to have a trunked pair due to the PBX only having 1 NIC.

Did look into using HP mesh but that only supports 5 switches.

Thx,
Karl.
Yan Henrichon
Frequent Advisor

Re: HP Trunking\Redundancy\2x Core's.

Hi Karl. Here is my advise.

What kind of traffic your edge switch "transport" to have the need of a trunk port?

As per the AIS ProCurve Certification, the trunk have to be coterminus. That means that the trunk needs to start from a switch and terminate to another. You can't split the trunk.

In that case, I would recommand this.
By example, connect port 25 of edge 1 to core1. Connect port 26 to core 2 and so on.
Configure MSTP on all switches and configure your path cost.
Turn on spanning tree.
Use a trunk of 2, 3 or 4 ports to connect both core and Tada, you have a redundant network.

BTW, HP full meshing support 5 switches but partial meshing support 8 but it's not worth it in your configuration.

HTH... Yan
Igor Ybema
Advisor

Re: HP Trunking\Redundancy\2x Core's.

> I need the cores to have a trunked pair due to the PBX only having 1 NIC.

What do you mean by this?

Just don't connect any server/host to the core and you are safe. Connect the PBX to a edge switch.

Karl Collinson
Frequent Advisor

Re: HP Trunking\Redundancy\2x Core's.

Morning,

The whole solution is for a VoIP install.
175 IP Hand sets.
1 PBX (Phone System) (PBX only has 1 NIC interface)

Using Interface 25+26 as a trunk to increase the bandwidth on each edge uplink.

Looked into the using diff versions of STP (M) is the only feasible version due to better VLAN awareness.

Itâ s not so much the uplinks from the edge to the core that is my concern.
Itâ s the single point of failure â The Coreâ .
â Incase of a failure the customer would only need to change the interface (core) the PBX is interfaced withâ due to the trunks being split between the cores.

So I am guess using Stacking and turning the additional switch\switches into one IP does not allow for trunk splitting?

Thx,
Karl.

Igor Ybema
Advisor

Re: HP Trunking\Redundancy\2x Core's.

As a pure switch (when you are not routing) IP does not do anything other than allowing you to manage the switch. So if you enter the same IP address on both switches, hence you will have problems managing both switches.

Using STP will give you the redundancy you need. Just forget the whole trunking and enable STP on all switches. Connect the PBX anywhere and replug it to another switch if that switch dies.
So, like this. Connect edge switch A and B to both cores. To prevent the loop, enable STP.
A---C1---B
|---C2---|

You can still go with the dual-core with trunking in the edge picture,.. however you can not connect hosts on the core switches as I have told earlier. Connect the PBX to an edge and if that one dies, connect it to another switch.