A DDoS mitigation service is more than just the technology or the service guarantees. The quality and resilience of the underlying network is a critical component in your armor, and one which must be carefully evaluated to determine how well it can protect you against sophisticated DDoS attacks.
Below are five key considerations in evaluating a DDoS scrubbing network.
When it comes to protection against volumetric DDoS attacks, size matters. DDoS attack volumes have been steadily increasing over the past decade, with each year reaching new heights (and scales) of attacks.
To date, the largest-ever verified DDoS attack was a memcached-based attack against GitHub. This attacked reached peak of approximately 1.3 terabits per second (Tbps) and 126 million packets per second (PPS).
In order to withstand such an attack, scrubbing networks must have not just enough to ‘cover’ the attack, but also ample overflow capacity to accommodate other customers on the network and other attacks that might be going on at the same time. A good rule of thumb is to look for mitigation networks with at least 2-3 times the capacity of the largest attacks observed to date.
It’s not enough, however, to just have a lot of capacity. It is also crucial that this capacity be dedicated to DDoS scrubbing. Many security providers – particularly those who take an ‘edge’ security approach – rely on their Content Distribution Network (CDN) capacity for DDoS mitigation, as well.
The problem, however, is that the majority of this traffic is already being utilized on a routine basis. CDN providers don’t like to pay for unused capacity, and therefore CDN bandwidth utilization rates routinely reach 60-70%, and can frequently reach up to 80% or more. This leaves very little room for ‘overflow’ traffic that can result from a large-scale volumetric DDoS attack.
Organizations deploy DDoS mitigation solution in order to ensure the availability of their services. An increasingly important aspect of availability is speed of response. That is, the question is not only is the service available, but also how quickly can it respond?
Cloud-based DDoS protection services operate by routing customer traffic through the service providers’ scrubbing centers, removing any malicious traffic, and then forwarding clean traffic to the customer’s servers. As a result, this process inevitably adds a certain amount of latency to user communications.
One of the key factors affecting latency is distance from the host. Therefore, in order to minimize latency, it is important for the scrubbing center to be as close as possible to the customer. This can only be achieved with a globally-distributed network, with a large number of scrubbing centers deployed at strategic communication hubs, where there is large-scale access to high-speed fiber connections.
As a result, when examining a DDoS protection network, it is important not just to look at capacity figures, but also at the number of scrubbing centers and their distribution.
A key component impacting response time is the quality of the network itself, and its back-end routing mechanisms. In order to ensure maximal speed and resilience, modern security networks are based on anycast-based routing.
Anycast-based routing establishes a one-to-many relationship between IP addresses and network nodes (i.e., there are multiple network nodes with the same IP address). When a request is sent to the network, the routing mechanism applies principles of least-cost-routing to determine which network node is the optimal destination.
Routing paths can be selected based on the number of hops, distance, latency, or path cost considerations. As a result, traffic from any given point will usually be routed to the nearest and fastest node.
Anycast helps improve the speed and efficiency of traffic routing within the network. DDoS scrubbing networks based on anycast routing enjoy these benefits, which ultimately results in faster response and lower latency for end-users.
Finally, when selecting a DDoS scrubbing network, it is important to always have a backup. The whole point of a DDoS protection service is to ensure service availability. Therefore, you cannot have it – or any component in it – be a single point-of-failure. This means that every component within the security network must be backed up with multiple redundancy.
This includes not just multiple scrubbing centers and overflow capacity, but also requires redundancy in ISP links, routers, switches, load balancers, mitigation devices, and more.
Only a network with full multiple redundancy for all components can ensure full service availability at all times, and guarantee that your DDoS mitigation service does not become a single point-of-failure of its own.
Ask the Questions
Alongside technology and service, the underlying network forms a critical part of a cloud security network. The five considerations above outline the key metrics by which you should evaluate the network powering potential DDoS protection services.
Ask your service provider – or any service provider that you are evaluating – about their capabilities with regards to each of these metrics, and if you don’t like the answer, then you should consider looking for alternatives.