Dan Siemon & Scot Loach from Preseem had the opportunity to go live on ISP radio’s latest show with hosts Steven Grabiel and Dennis Burgess on 4th April, 2018. The core agenda was to discuss, in-depth, the concept of packet buffering and it’s impact on subscriber’s quality of experience with an internet service provider.
The 1-hour long session was planned around following key topics of interest to all network managers and WISP operators –
- Understanding Packet queues and latency
- Why do network elements have queues?
- Impacts of queuing packets?
- Better ways to manage queues – AQM & FQ-CoDel
- How Netflix actually behaves on a network (hint: it’s not a stream)
While many WISPs joined and asked questions during the live show on ISP Radio and YouTube, it was recorded to be available for everyone’s benefit and here’s the video –
For those in a hurry, here are some of the key takeaways from the ISP Radio session –
1. Most WISPs and network operators believe that packet networks have high latency when they are loaded. This poor behavior is so prevalent that many think it is just the reality of the internet.
In reality, High latency under load is the result of poor packet queue management.
2. Buffer management is like the Goldilocks Problem. If you have too little buffer, you have poor link utilization. If you have a lot of buffer, there’s a lot of latency and therefore the interactivity of the network suffers.
Latest innovations in network science around Active Queue Management (AQM) allow WISPs to mitigate the big buffer problems through its intelligent and automatic choice of what and when packets to drop.
3. Advancements in algorithm like FQ-CoDel allow network managers to ensure that interactive applications like VoIP or gaming don’t get negatively impacted by high-bandwidth applications like Netflix streaming or device updates.
Subscriber complained that his game sessions were laggy while his wife watched Netflix. With Preseem’s plan enforcement, based on FQ-CoDel, his game latency stayed low while his wife’s video quality didn’t change.
4. Most ISPs enforce plan rates on some element in the network – Access point/ SM, Intermediate router/switch etc.
Typically all of these either do not have enough buffering or utilize a simple, deep tail drop queue which results in a very poor user experience under load. Such problems can be taken care by QoE-optimized plan enforcement based on FQ-CoDel.
5. Netflix is by far the most popular application on the internet. About a third of traffic on a typical ISP network is Netflix. Most WISPs consider Netflix as a stream like other applications.
In reality, Netflix downloads chunks of content to a buffer. It uses multiple TCP connections. Netflix videos are variable bitrate encoded making it impossible to limit resolution with network policy. Netflix downloads in short bursts at full link rate, which can negatively impact other traffic.
Subscriber/flow isloation (eg FQ-CoDel) can solve this problem.
There were some very interesting questions posed by WISP participants during and after the show. Some of these were:
Q – If one has a lot of bandwidth, can that take care of buffering and latency issues without the need for FQ-CoDel?
Dan – If someone has infinite back haul bandwidth, they won’t need FQ-CoDel but very rarely, does that happen for a typical WISP. Bandwidth is precious for almost all network owners and managers. Going beyond individual customer’s traffic management, FQ-CoDel helps fix network congestion at any part of a network. Whenever there’s congestion, there’s a queue and applications based on FQ-CoDel will help manage that problem.
Q – Where is the FQ-CoDel implementation on a typical WISP network?
Dan – Abstractly, it can be at any place where there’s a queue in the network. Talking about Preseem which uses FQ-CoDel to optimize QoE in a WISP network, it’s deployed at the highest point where there’s no asymmetry in a network. If a WISP has one individual transit link, we’re deployed in front of that. If there are multiple transit links, different boxes can be deployed running Preseem software and all data is collected and analyzed in the cloud with a collective presentation for the operators. For Preseem to apply fair shaping and per-flow prioritization it needs to own how plans are enforced and no other tool down in the network should prescribe the subscriber plans.
Q – Does Preseem function as the billing system’s radius client that actually controls the bandwidth for each individual subscriber?
Dan – Preseem has API integrations with 5 billing vendors like Sonar, Powercode, Azotel, VISP.net, Billmax and other custom integrations as well. Preseem just needs to be told which IP address belongs to which subscriber and their plan speeds and Preseem does the rest. It seamlessly integrates with billing systems used by WISPs. When the integration is turned on, Preseem gathers all the information on plan speeds and subscriber information and it just works.
Q – Can Preseem peer into unincorporated PPoE packets to do bandwidth control?
Dan – Yes, we have WISPs doing this. It’s just a configuration to say the subscriber traffic is inside PPoE or VLAN and it hops over the headers and get it done.
Q – Any stories from the WISP community where they used Preseem and saw dramatic improvements?
Dan – We have a lot of reviews. They are listed on the website here – https://www.preseem.com/reviews-testimonials-wisp-feedback/ . Most common feedback is when WISPs say that complaints of people with internet feeling slow during downloads or Netflix streaming have just gone away since Preseem was deployed to do QoE optimization and plan enforcement.
Q – Do you support bandwidth limiting customers with multiple IPs? For example – a customer has 10 Mb plan with multiple IPs?
Dan – Any IP is bound to a subscriber and if they go through the same box, they’d be grouped together under that subscriber’s traffic envelope. If you have two IPs with subscriber at 10 Mp then the two of them will be shaped at 10 Mb together. To avoid this, using plan identifier along with the subscriber identifier that can allow for separate 10 Mbs for each IP.
Watch the video for other questions!
Note – This is an edited version of ISP radio’s show on 4/4/2018. For the full version, please visit this link.
Preseem uses advanced queue management techniques, based on FQ-CoDel, to enforce subscriber plan limits and to manage streaming video and other high-bandwidth applications while improving your subscriber QoE. Preseem’s QoE optimization provides per-flow fairness and prioritization which allows interactive flows like VoIP, gaming & DNS to get through smoothly without being affected by bulk flows like streaming video and large Windows downloads. This ensures that your customers never call to complain about slow Internet while someone else in the house is streaming Netflix or doing a heavy download. Contact us for a free 30-day trial.