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Re: 10gbe uplink between 2910al and 2900

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Steve Hoddinott
Occasional Contributor

10gbe uplink between 2910al and 2900

I have an existing Procurve 2900(J9050A)  and have recently purchased a Procurve 2910al(J9147A).

I would like to connect (Just uplink not stack), the 2 switches using the 10Gbe CX4 ports, but I've been given conflicting information as to if/how this will work.


The Procurve 2900 came with 2 CX4 ports as default (marked as: A2 & A3 - 10Gbe CX4 Stacking Ports)

If I buy/install a 10Gbe CX4 (J9149A) module for the 2910al, will I be able to connect to  the existing ports on the 2900 or will I also need to install an additional module in the 2900, possibily a J8440A?


I would like to know if this will work before I start buying additional modules, so would be grateful for any information on linking these 2 switches.



Occasional Advisor

Re: 10gbe uplink between 2910al and 2900

The 10Gbe CX4 (J9149A) module for the 2910al is a two port CX4 module and has nothing to do with "stacking". If you buy one it will interface with the CX4 cable and the existing 2900 that has the two CX-4 ports. The module in the back of the 2900 is NOT a stacking module. It is simply a 10Gbe module with multiple ports. You can, if you desire, trunk the two CX-4 ports as a single trunk/LAG to have more bandwidth and redundancy. Making a "trunk" provides redundancy and bandwidth. Please dont confuse the term trunk with Cisco's vlan trunking. HPN uses 802.1Q vlan tagging which is the industry standard for vlan "trunking". Not the same but just stating this for clarity on terms. 

So 2910al CX4-------CX4 2900 = yes it will work fine.

2910al (2)CX-4 as trunk to (2)CX-4 2900 = will work fine and add redundancy and bandwidth

If you have two CX4 cables and can use both CX4 ports then might as well use it.

If your switches need to be in different locations and you plan to use fiber then yes you need optics which would be dependant upon the type of fiber you have and how far apart the switches are located.

The 2900 installation guide provides info in chapter 2 page 29 for optimizing the 10G connections.

Since A2 & A3 share a channel on the 2900 series the max throughput would be 14.4 Gbps if linked with port aggregation. (trunking)

So, brief answer to your question, Yes it will work with the CX4 ports on the 2900.


Occasional Advisor

Re: 10gbe uplink between 2910al and 2900

HP 2-port 10GbE CX4 al Module (J9149A)
2 CX4 10-GbE ports (IEEE 802.3ak Type 10GBASE-CX4)
Maximum distance:
15 m using CX4 cable
300 m using optical media converters and multimode fiber cable
Use CX4 10-GbE cable (0.5 m-15 m) or HP ProCurve 10-GbE CX4 Media Converter (J8439A). No CX4 cables are included with this module.
Please do not confuse this module with the inter-connect module!
Occasional Advisor

Re: 10gbe uplink between 2910al and 2900

I took a few minutes and looked back at the Install guide to see what could be considered "conflicting" information. From the verbage used in the guide the tech writer refers to the stack of three switches. That is only the placement of one on top of the other in reality. The 2900 series support IP stack management but do NOT support true stacking. The CX4 ports on the 2900 series are 10gig ports and NOT stack ports. You cant build a "stacked switch" with the 2900 series where they behave as a true stack. They are still cascaded one to another in reality. The 2910al does have the inter connect kit but that is what it is and NOT true stacking either. So the documentation can lead to questions it seems. The 2910al also has the optional SFP+ module for 10g connections so you do have options but the SFP+ module would only be useful with the 2900 series for fiber connections with fiber optic transceivers.


The line below refers to IP stack management and is just that:

The Series 2900 Switches can be connected together, through standard
network connections, and managed through a single IP address. Up to 16
switches can be connected together in such a “virtual stack”.


I wish the tech writer would not have introduced the stack management at that point in the description of the build of the simple topology with the 10g connections as it could be a little confusing or misleading. HP does have the newer 3800 series that do provide true stacking which is not the same as IP stacking or cascading switches. The illustration in the guide is a cascade of the switches in a stacked on top of one another manner.

Steve Hoddinott
Occasional Contributor

Re: 10gbe uplink between 2910al and 2900

Thanks for your thorough and complete explaination.

I had been confused by some of the documentation and had also been unable to get a straight answer from my suppliers. I will go ahead and order the CX4 module for the 2900al.