Cubro Blog

Case Study: Massive two-tier load-balancing solution from Cubro


The service provider wanted to do 6,5 to 7 TB session aware load balancing to a DPI application. However, the traffic was delivered asymmetric and over 90 x 100 Gbit links. Moreover, the traffic was from fixed net users and mobile users. The fixed net traffic was significantly asymmetrical implying that the request and answer were not on the same port, and the mobile traffic, as usual, was in the GTP tunnel.

Technical Solution:

Cubro offered a two-tier load-balancing concept which was based on EXA32100 and EXA48600. In the first stage, the GTP tunnel is removed from the mobile traffic which is the only solution for the asymmetrical traffic issue. Compared to other vendors, GTP tunnel removal in hardware is a standard feature on Cubro products even when the load is very high.

Cubro is able to identify the challenges the customers face and can provide the right solution. In this case, the asymmetrical traffic was a major issue, but Cubro solved this problem by developing a learning load balancing mechanism. This was only possible to develop because the EXA32100 has a high-performance host controller. The units are constantly learning all network relations and based on this information it was possible to solve the asymmetric traffic challenge. Besides this, the advanced network packet broker can remove several MPLS, VLAN, and VXLAN tags to make the traffic readable for the DPI.

In the second stage, we use 16 EXA48600 as output. Each of the 6 EXA32100 units was connected to each EXA48600. 

Hold on; you don't have enough ports! That is true for some other visibility vendors but not for Cubro because we can use input and output separately. We can feed 16 links / 32 ports to the unit and still have 32 optical outputs to forward the traffic to the second stage.

In order to handle traffic coming from different sources, you need several rules, and Cubro offers up to 8000 rules per unit. In the second stage, the user can do a "simple" layer 4 dual-stack (IPv4 and IPv6) session aware load balancing.

Session-aware load balancing is useful only if the session stays on the same probe forever. This is possible with Cubro monitoring load balancing application which is a unique feature of Cubro product. This works differently than a standard switch load balancing.

A usual hash-based load balancing is designed for live traffic. Therefore, the load balancing cannot assure that every hash has a deterministic port relation. This means the load balancing is session aware but not necessarily forwarded to the same port. Especially, when a session stops for a while, then it can happen that after restarting the session is on another port. This is not good for monitoring because this means the traffic is on another probe. We at Cubro don't do that, and our hash has a deterministic port relation!

Business benefits:

  • Effective network traffic management
  • Reduced MTTR
  • Capex and Opex savings
GTP Load Balancing in Hardware with EXA32100


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Saturday, 17 March 2018