“Swedish ISP Com Hem
used Varnish to power
seamless OTT live andVoD video streaming,manage growing
amounts of data and tobuild their own CDN.”

CASE STUDY : SFR Telecommunications

Case Study:Com Hem1

We launched Varnish on a Friday afternoon
right before streaming a big sports event, andit worked flawlessly
Background
ISPs throughout Europe look for ways to remain commercially and technically competitive while providing
service quality and customer satisfaction. Com Hem aims to do this by offering reliable, fast service across theirofferings, differentiating their offer and of course securing customer retention and growth by leveraging theirindividual strengths. One of these strengths is their continual technology innovations, aimed at anticipating theneeds of the market and the trajectory and trend of the technology they use.
One major component of ensuring continued growth and innovation is Com Hem’s drive to offer seamlessstreaming video. As a market-leading provider of TV and high-speed internet, Com Hem is well-prepared to
manage the technical and growth-related challenges as they come. Nevertheless, implementing the right tools
to future-proof the platform and ensure flexible, continued development put Com Hem at a crossroads. With
more users demanding speed, seamless streaming of live and VoD OTT video and instant access to streaming
video across all their de vices, Com Hem’s need in taking their platform to the next level with a video-streaming
solution required both flexibility and the ability to cope with the inherently unpredictable nature of user demand(i.e. both peak traffic during predicted events as well as unexpected traffic spikes). Com Hem needed a solutionthat could offer scalability and the kind of flexibility that would enable growth and speed without being confinedby “black box” products that lacked options for customization.

Com Hem at a glance
CompanyCom Hem Group offers broadband, TV, play and telephony services
to Swedish households and companies. Their powerful andfuture-proofed net work offers speeds up to 1 Gbit/s, covers half ofthe country’s households, making the Com Hem Group an importantdriver of creating a digital Sweden. They bring their 1.45 million
customers the largest range of digital-TV channels and play services
via set top boxes as well as on-the-go for tablets and smartphones.

ChallengeCom Hem wanted to offer seamless, reliable, high-performance OTT(live and VoD) video streaming by building their own DIY CDN withwhich to serve and control content.

Varnish solutions for Com Hem•

Started using Varnish Cache as an image CDN and web
accelerator for apps and TV services. Turned to Varnish
subscription in 2017 to create DIY CDN exclusively for video
streaming services.

•Professional expertise/support from Varnish core developers•Using Varnish High Availability to replicate cache data; Massive
Storage Engine; Hitch/TLS/SSL•All HTTPS streaming is done through Varnish Streaming Server;
traffic is constantly and exponentially growing

CASE STUDY : ComSFR Telecommunications
Hem2

The Challenge:
Varnish lets us manage the samedata using different kinds of requests
from the same cache. This saves
bandwidth and cache capacity. WithVarnish we can tune to our needs
and optimize our cache. Varnish
gives us this flexibility to control theflow in a very neat way.

Tasked with continuously looking toward
the future to prepare services for delivering
the next level of user experience, the teamresponsible for Com Hem’s video streaming
infrastructure needed to find a more flexible
video streaming solution.
A few activities formed the framework of what
Com Hem wanted to achieve:• Developing a pure HTTP video streaming CDN/
streaming platform to serve and control theirtraffic, taking advantage of their own load-balancing
capabilities alongside cache replication and cachestorage routing based on content

Adam Palmblad, TV Architect, Com Hem”

• Replacing existing video streaming technology with amore flexible, customizable solution at more trans parent,predictable price point• Managing a large amount of data with room to grow
• Protecting the backend/origin from being overloaded during peaktraffic periods/big events

The Solution:
Flexible control of content and streaming with flexibility: Building an in-house DIY CDN and leveraging
control of caching logic
Com Hem had a streaming-server solution in place already, but it did not offer the flexibility they needed togrow. This streaming server would not only have forced them to cede more control of their content and how it
was delivered but would have added prohibitive new costs to their video streaming operations. The prospect ofballooning expense coupled with diminishing flexibility and control could no longer serve Com Hem’s needs,
which led their team to search for a way to take back control, both of content
and costs. In their search, they found Varnish.
Back to basics: Cache control
With this in mind, one of the first drivers for Com Hem
in seeking out Varnish was the transparent andflexible approach to caching; ultimately, Com Hem
could completely control how they cached theircontent. With Varnish, Com Hem delivers
OTT live content, catchup/VoD content, andthough they are delivering the same data,
the requests are different, which saves agreat deal of cache capacity.
Bottom line: Cost control
Cost of video delivery is a big
consideration, particularly
when the amount of video you
serve continues to grow. Cost/
pricing motivated the initial
shift to choosing Varnish froma business perspective. Varnish
has offered Com Hem a full suiteof flexible solutions at a flat rate,
while other solutions tacked on
additional costs for additional
licenses or features while offering
less flexibility.

CASE STUDY : Com
SFR Telecommunications
Hem3

Results: Go your own way: Building a self-managed video streaming CDN
solution implementing Varnish: how, when, what
How and when
When Com Hem investigated its options and settled on Varnish, they discovered that implementation was fastand easy, particularly with the support of Varnish Software’s engineers. A working design was ready within amonth, and with two or three more months of extensive testing and methodical planning and discussion, thesolution went live. The Com Hem team knew that the old solution would have failed under the load of an upcoming sporting event and, with full confidence in the Varnish solution, they moved all traffic over to the Varnish
solution at once without a more conservative, incremental migration period.
According to plan, the Varnish implementation was immediately put to the test when Com Hem launched it on a
Friday afternoon ahead of a big, live sporting event; Varnish served the video seamlessly. Varnish worked underload conditions and has continued to perform ever since.
What
Com Hem has been streaming on the web for four or five years, and although historically, they have seen low
figures in terms of data, this has begun to grow rapidly and exponentially in the last year. Early in 2017, whenCom Hem adopted Varnish, Com Hem knew that existing capacity would not be sufficient for future demands.
When Varnish entered the picture, Com Hem saw an average of about 5GB per day, which has jumped to peaksof 60GB (expected to continue growing).
About a quarter of Com Hem’s traffic today is served from the backend. Varnish manages this handily with thecapacity to expand as Com Hem requires. As traffic for Com Hem is mostly live (VoD consumption is likely toincrease considerably in coming months with the introduction of a new video rental service), it makes sensethat hit rates are highest for this type of traffic.
Naturally, streaming traffic can be unpredictable. Com Hem does employ a sophisticated, granular monitoring
system to oversee bitrates, where traffic goes, flows and so on, but this is not yet implemented in the Varnish
data center, so predictive analysis of streaming-specific traffic is something that is coming in the future once
this granular-level monitoring is deployed for the Varnish servers as well. In the meantime, having Varnish inplace means that sudden traffic spikes, though unpredictable, will be manageable.

“Varnish performs exactly
as promised, and that is thebenefit. Things will not break,regardless of traffic spikes.
We launched Varnish on a
Friday afternoon right before
streaming a big sports event,and it worked flawlessly.”

CASE STUDY : Com Hem

4

Future-Proofing: through a do-it-yourself approach Varnish enables anall-in-one solution
Fundamentally, Com Hem benefits from the flexibility they have gained not just by being able to do what theywant today, i.e. creating a robust video streaming solution and building their own self-managed CDN, butin being able to foresee future needs and adapt for them using existing Varnish features. As they see traffic
volumes grow, Varnish expands to accommodate. Overall, by adopting Varnish and using Varnish design, Com
Hem has been able to reduce the number of components in the whole solution, leading to a simpler, morestreamlined and self-managed approach, all without additional investment.
• Caching and edge logic is now in Com Hem’s hands, so they can respond with agility to changes in broadcast
and OTT. The Varnish Configuration Language (VCL) unlocks unlimited potential for configuring the kinds ofpolicies and rules that suit Com Hem’s own needs, particularly when they need to do specific things in specificstreams. VCL enables Com Hem to get closer to the end user implementing logic at the edge (speed and moregranular personalization).

Level 7

“The high-performance
Varnish nodes are thehardest working nodes of allin our set-up. People think
it is interesting and it gets
attention internally.”

LoadBalancing

Handles

100’sTB Data• Com Hem adopted a straightforward and very fast load-balancing approach. They didn’t want to implement
another complex technology to handle load balancing (as they were trying to streamline and simplify). Without
going into too much detail, with Varnish, only the caching layer needs to scale even as bandwidth needs grow.
But they also wanted level-7 load-balancing so that caches are efficiently used (that is objects are not copied allover the platform, but only on a pair of servers). This was handled by allocating servers into colour groups (red,blue, etc) and each request was “hashed” into a colour (identical requests get hashed into the same colour).
If a server gets a request matching its colour, it serves that request from cache or goes to the backend. If thecolours don’t match, Varnish acts as a load balancer, bypassing its cache and routing to a node with the rightcolour.
• Varnish Massive Storage Engine (MSE) ensures that as the demand for VoD grows, persistent storage isavailable for long-term storage and already delivers a better ability to decide what to cache and what not to as
well as simplifying configuration of and dimensioning of the server. While Com Hem does not yet need to use
MSE to its full potential, this will become necessary as customers begin to access the VoD library and selectfrom it more sporadically (i.e. the long tail of content). On the Com Hem platform, users can choose and playwhatever content whenever and wherever they wish, up to two weeks in the past, which is a lot of data for 150
channels (i.e. 100s of TB of data that make up the live startup and start-over content). The functionality of MSE
will become more and more important as time goes on because of the growth in VoD content.

CASE STUDY : Com Hem5• Varnish High Availability (VHA) adds robustness and stability from the beginning, ensuring resilience. VHA is
important for their CDN design to ensure that the information within each cluster stays in sync. They can also
take down one node with less impact. VHA also enables Com Hem to do stateless design, which means they do
not need a load balancer. VHA is one component that contributes to how Varnish is a safety net that prevents
catastrophic failures when a site is overloaded with traffic.
• Varnish has TLS/SSL support for HTTPS with Hitch. All content providers (e.g. Apple, Android) require HTTPS
streams. Com Hem needed to ensure HTTPS streams, but this, too, was a feature that would have createdadditional expense in added hardware needs in order to serve the same capacity (or, without new hardware
investment, HTTPS would reduce current server capacity by half, which was untenable).
• Along with the open-ended flexibility to create what they needed, Com Hem found the support they received
from Varnish engineers to be both tactical and consultative, helping them to get the most from their Varnish
subscription at the same time as making their set-up more robust and future-oriented. After implementation,
Varnish support has continued to respond quickly to questions as they arise."

The Future
Com Hem will continue to work with Varnish features and VCL to further develop and tune their
video- streaming CDN solution. In addition to working more with MSE for storage needs, they hope to look atsession handling, introducing a kind of tokenized system for authenticating and authorizing access to content
another function Varnish can handle. Indeed the idea is to introduce more Varnish functionalities into the setup,
as that is where everything is happening.

“Although VCL adds a slightlearning curve, it is where
the magic happens and it
is totally crucial. VCL allows
for valuable flexibility, forexample, in ad replacement”.

CASE STUDY : Com
SFR Telecommunications
Hem6

Los Angeles - Paris - London
Stockholm - Singapore - Karlstad
Dusseldorf - Oslo - Tokyo

www.varnish-software.com
CASE STUDY : SFR Telecommunications

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