The Need for a WISP Bandwidth Control or Traffic Management Solution
Whether its optimizing use of backhaul capacity or selling plan speeds based on customer needs, almost all WISP owners or operators need a bandwidth control solution. Some WISPs refer to bandwidth management as traffic shaping or rate-limiting, while others call it plan enforcement. Beyond the terminology, the importance of an effective WISP bandwidth control solution cannot be understated.
Subscriber needs vary. As a result, most WISPs sell plans with speeds like 10 Mbps down and 1 Mbps up for small families. Or 25-50 Mbps or more for gamers and heavy video streamers or downloaders.
From an enforcement perspective, many WISP owners and operators think that as long as they have a bandwidth control or management solution that limits the customer to their speed and plan, that’s enough.
In reality, however, there’s a lot more to WISP bandwidth control solutions than the simple enforcement aspect. More importantly, how WISPs rate limit or enforce their subscriber plans has a large impact on the customer experience.
How WISPs Enforce Bandwidth Management Matters
Almost all WISPs enforce subscriber plans. The choice of a WISP bandwidth control or traffic shaping solution has a direct impact on subscriber Quality of Experience (QoE).
Poor plan enforcement typically leads to ‘my-internet-is-slow’ calls. Generally, when a customer calls in with this kind of complaint, they might be downloading the latest Windows update, using Netflix, or otherwise hitting the bandwidth limit of their plan or connection. This doesn’t have to be the case. This bad QoE is the result of using poor plan enforcement techniques.
Many WISPs deploy one of the following three WISP bandwidth control methods. While each does a good job of basically limiting customers to their plan speeds, their impact on QoE is often not understood by WISPs.
1. Access Point (AP) Enforcement
Most AP hardware allows WISPs to set per-subscriber bandwidth limits directly on an access point. AP bandwidth shaping tools use simple queueing techniques. With simple queues, if more data comes in than what the queue can handle, packets are either dropped or buffered. This can lead to Bufferbloat problems or slow-internet complaints when multiple users in the home are online at the same time. In most cases, this leads to a very poor subscriber experience and complaints that require costly customer support or site visits.
Bottom line: AP-level shaping tools use simple queuing techniques which allow heavy/bulk applications like streaming video (for example, Netflix) to negatively impact the performance of smaller/more interactive applications (like gaming, VoIP, and DNS queries). So if a household is streaming video and maxes out their plan speed, all other applications/users will suffer.
Some WISPs use scripts or rules set in their edge routers (like a Mikrotik) or customer-premises equipment (CPE). Due to hardware limitations, these platforms also use simple queuing techniques which let heavy applications negatively impact performance. Similar to AP-level enforcement, router-level traffic enforcement or shaping is incapable of subscriber-aware policies such as multi-site bandwidth limits.
Bottom line: Router or CPE-level shapers use simple queuing techniques that allow heavy applications like streaming video to negatively impact the performance of interactive applications.
3. Application-Aware (DPI-based) Traffic Management Tools
Some network managers choose solutions that inspect individual applications. These solutions use a complex set of rules to treat individual traffic flows differently and set individual priorities. For example, a WISP will set manual rules like capping Netflix traffic at ‘X’ Mbps, VoIP at ‘Y’ Mbps, and so on. DPI-based solutions require constant tweaking and upgrades to stay current with the rapid changes in applications. Also, setting arbitrary bandwidth limits is inherently complex and time-consuming. For example, it’s impossible to know the appropriate rate to shape Netflix, as it varies with the video encoding, content, and even the type of device that’s playing the content. Worse, setting these values incorrectly can make the subscriber QoE worse than having no bandwidth control solution at all. Furthermore, with an increasing amount of encrypted traffic, DPI-based bandwidth control solutions have declining utility.
Bottom line: DPI-based application-aware solutions use simple queue techniques and are inherently costly, operationally complex, require constant tweaking, and have declining relevance given the rise of encryption.
Bandwidth Control: There’s a Better Way
When it comes to effectively managing bandwidth and enforcing subscriber plans, there’s good news for WISPs. Much progress has been made in the field of active queue management (AQM) in recent years. One innovation coming out of the IETF (Internet Engineering Task Force) is FQ-CoDel. This algorithm is a combined packet scheduler and AQM technique developed as part of the Bufferbloat-fighting community effort that’s also application-agnostic.
In the approach shown on the right, flows are automatically categorized into bulk or interactive based on how much queue they build up. So, applications like streaming video or Netflix get categorized as bulk flows.
On the other hand, VoIP, gaming, or DNS queries that are latency-sensitive get categorized as interactive flows and are instantly prioritized.
As a result, even when a customer maxes out their plan with Netflix or other heavy downloads, the other applications don’t feel slow. The overall experience is much better.
Preseem QoE Optimization and Bandwidth Management
Preseem uses FQ-CoDel to offer an easy and effective traffic shaping and plan enforcement solution. This QoE-optimized bandwidth control solution helps ISPs:
- Keep just the right amount of queue in the device to ensure high link utilization and low latency
- Ensure per-flow fairness and prioritization (interactive flows get implicitly prioritized to the front, avoiding any impact from bulk applications)
- Avoid complex policies, arbitrary rules, or encryption concerns
ISPs that deploy Preseem’s QoE optimized shaping (based on FQ-CoDel and AQM techniques) get:
- Happier Customers
- Lower Churn
- Fewer Support Calls
- Fewer truck rolls/support costs
- Better bandwidth utilization
- Delayed network investments or upgrades
For more information on Preseem’s QoE monitoring and optimization platform, click here to book a demo with us.