Limit of 15 interfaces on a class?

[kapow]

I had to add several new outbound interfaces to a customer class and ran into an issue when provisioning the application:

16 interfaces on the component 'test-kapow-net:main.Rails' exceeds max of 15.

Is this limit adjustable in any way? I may need quite a few more to connect to a farm of application servers.

[PeterNic]

No, unfortunately, this is fixed at 15. The limit comes from the underlying virtualization system; it is documented, together with other dimensions at http://doc.3tera.net/AppLogic2/ReleaseNotes-2-1-1.html#Product_Characteristics. We are working to raise the limit of virtual interfaces in future versions.

There are several alternatives, however (I am assuming you have a load balancer or traffic dispatcher):
- you can chain (see figure)
- you can cascade (see figure)

Both options have their advantages and drawbacks, depending on what you do. Chaining is better when there is an inherent priority, so the first switch holds the more frequently used paths; cascading is better when you need larger number of ports and similar propagation time.

Finally, it is possible to use multiple IN/INSSL gateways and do round-robin DNS between them. This way, in addition to getting more ports, you also get much more bandwidth -- as each gateway is capable of bringing a full duplex 1 Gbps. (see figure)

Regards,
-- Peter