What is the difference between Fixed, Pooled capacity and Flexed capacity?
There were changes in 2024, maybe you missed this.
Hello!
Citrix/NetScaler have a habit of changing how things are licensed, this can make it tricky to know what upsides & downsides are to a newer approach. Last year the concept of Flexed capacity was added, this has been positioned as a replacement for Pooled capacity in its various guises.
A colleague of mine, Robert, asked if there was a summary document that covered the differences, which would make it easier to understand the impact of the changes. I think there are a few, but maybe I could make something a bit more targeted.
What are the differences? Should I be concerned if the representative starts talking about the new offering but I am happy with pooled?
As I started to create this piece, I thought it might be useful to cover fixed licenses too. This would allow a complete picture of the options. The agenda will be:
What is this all about?
NetScaler Form factors?
Types of license?
Renewal options?
Terms used in this piece:
Fixed licenses have a fixed term(duration) and capacity, and will be referenced as ‘fixed’
Flexed is also called Universal Hybrid Multi-Cloud (UHMC) or Platform. I will refer to Flexed as UHMC in this document.
1. What are you talking about?
NetScaler is a security appliance, it can be used for many different things. In terms of paying for it, a NetScaler has been available to buy in a couple of different types of capacity or form factor. These form factors have been assessed in a couple of different ways:
Capacity has been measured in ‘the sum of all received bandwidth’. Exceed that number and the appliance will drop the excess traffic.
The number of cores that can be spun up to process traffic. This was used on virtual (VPX - hypervisor-based) instances only. A more simple approach.
In addition to the form factor, there are also feature bundles, which will govern what feature you can enable.
2. What about form factors then?
There are a few different types, that fall into two main classifications physical and virtual.
Physical types.
There are two main physical types. A NetScaler MPX is the single-tenant physical appliance, as of today there are two models a MPX 91xx and a MPX16xxx. There is also a SDX as its multi-tenant brother, these are typically very similar hardware appliances. In the SDX16xxx it does have 256GB of system memory which is twice that in the MPX version.
An important consideration is that each of these appliances, can be used with a range of throughput capacities. This is important later on.
NetScaler MPX/SDX 91xx runs from 5Gbps up to 95Gbps.
NetScaler MPX/SDX 16xxx runs from 30Gbps up to 250Gbps.
Virtual Types
There are several virtual types. A NetScaler VPX is a virtual appliance that can run on a hypervisor, either a XenServer, Hyper-V, vSphere or KVM. A NetScaler BLX runs ‘within’ a Linux operating system, it can use DPDK to boost SSL performance if required. There is also a NetScaler CPX, which can run inside a docker host as a container.
An important consideration is that each of these appliances, can be used with a range of throughput capacities. This is again important later on.
NetScaler VPX runs from 10mbps up to 100Gbps.
NetScaler BLX runs from 1Gbps up to 12Gbps without DPDK, it runs from 1Gbps to 100Gbps with DPDK.
NetScaler CPX runs from 1Gbps to 10Gbps.
Types of license
Now that we have the factors explained, I will cover what the options are for buying capacity and enabling features. Capacity comes in two types:
Fixed capacity (with a fixed term duration)
Flexible capacity (also with a fixed term duration)
Bundles are also two types now: Advanced or Premium.
Fixed capacity
This has a defined amount of traffic that can be processed, there are now these options.
VPX:
NetScaler VPX 1Gbps with an Advanced feature set.
NetScaler VPX 5Gbps with a Premium feature set.
NetScaler VPX 5Gbps FIPS with a Premium feature set.
Note: This VPX fixed license can also be used with a BLX form factor, capacity and feature limits still apply as a VPX.
MPX:
NetScaler MPX9105 with a 5Gbps Premium feature set.
NetScaler MPX9110 with a 10Gbps Advanced feature set.
NetScaler MPX9120 with a 20Gbps Premium feature set.
NetScaler MPX8910 FIPS with a 10Gbps Advanced feature set.
NetScaler MPX9130 FIPS with a 30Gbps Premium feature set.
FIPS is a bit of a special case, the customer will usually know if they need it as they will ask for it.
SDX
NetScaler SDX16030 with a 30Gbps Premium feature set.
NetScaler SDX16060 with a 60Gbps Premium feature set.
Fixed capacity deployment: These are typically local license files on each appliance, nothing else is needed.
Pros: Simple, specific capacity.
Cons: Doesn’t allow for dynamic changes (remember Covid19?). The capacity is tied to an appliance.
Flexible Capacity
Looking at the fixed options above, the obvious issue with fixed capacity is:
What if I need a bit more capacity? There was a concept of burst licensing, that could allow a 3-month surge in capacity, but it was a bit disruptive(reboots).
Also, what good is capacity tied to an appliance in Dallas, if the capacity issue is in New York? The answer is to make the capacity flexible, the dynamic dc!
Flexible capacity version 1 - Pooled Capacity.
The obvious solution is to provide a subscription of capacity that is hosted on a licensing server, in this case, NetScaler ADM. This later became NetScaler Console.
Typically, this was sold as a ‘pool’ of bandwidth and instances for a specific appliance. Let’s assume that a SDX 16030 is the appliance of choice, the 16030 will have 30Gbps of throughput and there will be 20 virtual instances running on this SDX.
Pooled gives me a bit of flexibility, according to the tables here, I can draw down 15Gb of the 30Gb of throughput and use it ‘elsewhere’ for VPX’s on vSphere. Along with 19 of the instances, leaving just 1 on the SDX.
Assuming, I have a couple of SDX’s of the same type this would double the draw-down options. Pooled also brought in the option to dynamically add capacity without reboots to the appliance, just add it to NetScaler Console and then assign it.
So, I can switch form factors, but there are limits.
Pooled - vCPU
There was a virtual-only option, so it does not get used on physical appliances, to have NetScaler VPX ‘cores’. This was a simple option that allowed the customer to have a bag of cores, they came in packs of 10,20 or 40 cores. Assuming you have 20 cores, you could choose to spin up 10, two-core NetScalers. Alternatively, you could have just one big one…
Flexible capacity version 2 - UHMC and Platform
What changes when I move to UHMC? UHMC includes 1000G of throughput along with 999 instances. The platform license effectively makes the capacity and instances numbers unlimited.
I can do what I want, I don’t need to draw down capacity from one environment(that 16k) to spin up another. There have been a few changes that came in at the same time.
UHMC and Platform have decoupled hardware and software, which means that you can now plug in any NetScaler hardware you need. A one-off cost adds a lifetime RMA to appliances sold before 4th March 2024.
New physical appliances are now sold with a lifetime hardware RMA along with dual power supplies included.
If you need a 10minute RMA, simply buy a spare box, or bring in one you have.
Rather than being limited to VPX, MPX or SDX, flexed works across all types.
As the capacity numbers are so much bigger, it opens up the options to look at other potential NetScaler use cases in other parts of the business.
When looking at the fixed licensing options that are available now, some options, such as a SDX91xx, are only available with UHMC.
If you are coming from vCPU, UHMC effectively gives you an unlimited number of cores! Just add memory to get more cores.
Allows the use of the complete capacity of a physical appliance, for a SDX16xxx this could take 250Gb and 55 instances!
Flexible capacity deployment: Requires NetScaler Console on-premise or Service, this isn’t optional.
Pros: UHMC allows for a global NetScaler deployment, and could allow the replacement of ‘other’ load-balancing devices.
Cons: Not much(in my opinion!).
What can be renewed today?
Pooled (both bandwidth and vCPU) has been replaced by UHMC/Platform, so Pooled is not renewable anymore. The recommendation is to move to UHMC unless there is only going to be a small tactical NetScaler requirement.
What can be bought new?
There are two options, fixed licenses or UHMC(Platform).
Summary
Hopefully, this has offered some pointers. I appreciate that every customer is different and sometimes a conversation is better. Let me know if this requires more details.