QOS Management Helps Operators during the Pandemic

April 24, 2020
Quality of Service
Availability and quality of Internet connection are the main indicators Broadband provider’s work.
QOS Management Helps Operators during the Pandemic

The channel bandwidth gets pretty much consumed when the users begin to whatch youtube, play online games or work from home. This results in random sessions breaking with stuttering sound and video, poor connection quality, slow web-pages loading – and annoying the subscribers.

The solution is to control the quality by prioritizing traffic in common channel.

Quality Of Service is a technology that prioritizes all traffic and provides the most popular applications, protocols and directions with a wider bandwidth. This allows the Internet Providers to maintain the quality of users’ experience (QOE) without changing the network layout.

Benefits:

  • quick start
  • no need to integrate with billing system
  • the result is preservation of channel capacity despite the increased traffic volume consumption.

Case study

Soon after the pandemic was announced, a Broadband provider from Lebanon contacted us. The operator provides Internet access to a sufficiently large number of subscribers (about 2.5k), while having a channel width 250 Mbps). There is no technical opportunity to expand the external channel.

After local companies have transferred employees to remote work, the amount of traffic increased significantly. For the subscribers this led to lowering the quality of Internet connection: jitter increased, tangible delays (more than 100 ms) appeared. Customers began to complain about slow loading, problems when watching videos and online gaming.

The were two possible ways of solving the problem:

  1. To rent a wider channel from the uplink provider and to upgrade equipment. This solution is technically challenging and takes too much time.
  2. To use VAS Expert policer, which allows to prioritize protocols and correctly use the available width. This way allows you to use the existing channel width without replacing the equipment and has lower cost.

After DPI and the QoE module were installed, our engineers started to analyze the network to find the most popular services and protocols. The higher priorities were chosen for such and other critical services. This includes messengers\Facebook to stay in touch with coworkers and family and VPN for remote work. The lower priorities were given to the time-insensitive services.

Protocols analysis

The analysis led to the following picture:

ftp cs0
ssh cs0
dns cs0
HOLAVPN cs0
HOTSPOTVPN cs0
IPv6-ICMP cs0
webaccess cs0
openvpn cs0
xmpp-client cs0
icmpd cs0
cslistener cs0
stun-behavior cs0
ipsec-nat-t cs0
ghvpn cs0
ICMP cs0
ICMPv6 cs0
GRE cs0
CHAMELEON cs0
OPENVPN_UDP cs0

xbox cs1
savant cs1
QUIC cs1
TELEGRAM cs1
sip cs1
commtact-http cs1

WHATSAPP cs2
l2tp cs2
pptp cs2
ESP cs2
AH cs2
microsoft-ds/smb cs2
isakmp cs2
pkt-krb-ipsec cs2
UDP Unknown cs2
WHATSAPP_VOICE cs2
VIBER_VSTREAMS cs2
FACEBOOK cs2
FACEBOOK_TRACK cs2
FACEBOOK_APPS cs2
FACEBOOK_CHAT cs2
VIBER cs2
Skype cs2

TCP Unknown cs3
RTP cs3
https cs3
SSL Unknown cs3

GOOGLEVIDEO cs4

http cs5

default cs6

Bittorrent cs7

We have to mention the Netflix protocol which did not become a high priority. The matter is that Netflix uses native protocols for certain streaming platforms (Windows, IOS, Android, etc). Support of such protocols is under development.

Therefore, a DPI-based solution offers the possibility of prioritization with the further use of policing depending on protocol signatures and traffic direction.

What does prioritization by traffic direction mean?

The DPI platform can determine a range of AS, towards which the traffic is considered a higher priority.

Getting back to Netflix, the experience show that this service has its own AS (ASN 2906). Now we only have to set priority assigned to the traffic for this AS.

Since Stingray Service Gateway already has an automatically updated list of global autonomous systems, it is enough to indicate the number of this AS and its priority. DPI also allows you to combine operator subnets into local ASs.

Finally the prioritization by direction is as follows:

2906 cs3
2914 cs1
16509 cs1
65502 cs1
65503 cs1
65504 cs1
65505 cs1
132203 cs1

To finish configuration we have to set policing rules for each class:

The limit is 240 Mbps for total outgoing traffic.
For classes:

Class 0 – rate 20 Mbps ceil 240 Mbps 
Class 1 – rate 40 Mbps  ceil 240 Mbps
Class 2 – rate 70 Mbps  ceil 240 Mbps
Class 3 – rate 83 Mbps ceil 240 Mbps
Class 4 – rate 20 Mbps ceil 240 Mbps
Class 5 – rate 5 Mbps ceil 240 Mbps
Class 6 – rate 1 Mbps ceil 240 Mbps
Class 7 – rate 1 Mbps ceil 240 Mbps

For total incoming traffic the limit is also 240 Mbps.
And similarly for classes:

Class 0 – rate 20 Mbps ceil 240 Mbps
Class 1 – rate 40 Mbps ceil 240 Mbps
Class 2 – rate 70 Mbps ceil 240 Mbps
Class 3 – rate 83 Mbps ceil 240 Mbps
Class 4 – rate 20 Mbps ceil 240 Mbps
Class 5 – rate 5 Mbps ceil 240 Mbps
Class 6 – rate 1 Mbps ceil 240 Mbps
Class 7 – rate 1 Mbps ceil 240 Mbps

After Stingray SG with Quality of Service was implemented, the situation got better: delays decreased and jitter decreased. Also, the number of complaints from subscribers has decreased – the problems of slow loading and delays in online games have been eliminated.

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