What is 5G NR all about? Check out this presentation to see all the key design components of this new unifying air interface for the next decade and beyond.
More than a decade ago, Cisco introduced wireless solutions that addressed challenges associated with address mobility, seamless authentication and comprehensive backend accounting.
In the last few years, the industry has transformed to offer an immense range of Smart Devices. This unprecedented growth in mobile traffic demands a change to scale to the new reality of any–to-any connectivity. This is a technical deep dive presentation on BNG Deployments and Mobile Offload techniques
What is 5G NR all about? Check out this presentation to see all the key design components of this new unifying air interface for the next decade and beyond.
More than a decade ago, Cisco introduced wireless solutions that addressed challenges associated with address mobility, seamless authentication and comprehensive backend accounting.
In the last few years, the industry has transformed to offer an immense range of Smart Devices. This unprecedented growth in mobile traffic demands a change to scale to the new reality of any–to-any connectivity. This is a technical deep dive presentation on BNG Deployments and Mobile Offload techniques
A short introductory presentation/video explaining Bandwidth Parts in 5G and why are they needed.
There are two main reasons:
1. Cheaper devices may not want to support the large bandwidth in 5G, that can go up to 400 MHz for FR2 and 100 MHz for FR1
2. A device does not need to monitor the whole of bandwidth for power consumption reduction reasons, here BWP can help too
HTTP/3 is designed to improve in areas where HTTP/2 still has some shortcomings, primarily by changing the transport layer. HTTP/3 is the first major protocol to step away from TCP and instead it uses QUIC.
HTTP/3 is the designated name for the coming next version of the protocol that is currently under development within the QUIC working group in the IETF.
HTTP/3 is designed to improve in areas where HTTP/2 still has some shortcomings, primarily by changing the transport layer. HTTP/3 is the first major protocol to step away from TCP and instead it uses QUIC.
Daniel Stenberg does a presentation about HTTP/3 and QUIC. Why the new protocols are deemed necessary, how they work, how they change how things are sent over the network and what some of the coming deployment challenges will be.
The new 5G unified air interface is being designed to not only vastly enhance mobile broadband performance and efficiency, but also scale to connect the massive Internet of Things and enable new types of services such as mission critical control that require ultra-low latency and new levels of reliability and security. The new design will unify diverse spectrum types and bands, scale from macro deployments to local hotspots and efficiently multiplex the envisioned 5G services across an extreme variation of requirements.
For more information on 5G technologies, use cases and timelines, please visit us at www.qualcomm.com/5G.
A Proxy Server is computer that functions as an intermediary between a web browser (such as Internet
Explorer) and the Internet. Proxy servers help improve web performance by storing a copy of frequently
used webpages. When a browser requests a webpage stored in the proxy server's collection (its cache),
it is provided by the proxy server, which is faster than going to the web. Proxy servers also help improve
security by filtering out some web content and malicious software.
A Proxy Server is a server (a computer system or an application) that acts as an intermediary for
requests from clients seeking resources from other servers.
Webinar topic: BGP on RouterOS7 - Part 1
Presenter: Achmad Mardiansyah & M. Taufik Nurhuda
In this webinar series, How BGP on RouterOS7 works
Please share your feedback or webinar ideas here: http://bit.ly/glcfeedback
Check our schedule for future events: https://www.glcnetworks.com/en/schedule/
Follow our social media for updates: Facebook, Instagram, YouTube Channel, and telegram also discord
Recording available on Youtube
https://youtu.be/CYTHOlY4WU0
GRX is the global private network where telecom network operators exchange GPRS roaming traffic of their users. It’s also used for all M2M networks where roaming is used, and that is the case from some company’s truck fleet management system down to intelligence GPS location spybug tracking system.
GPRS has been there from 2.5G GSM networks to the upcoming LTE Advanced networks, and is now quite widespread technology, along with its attacks. GRX has had a structuring role in the global telecom world at a time where IP dominance was beginning to be acknowledged. Now it has expanded to a lightweight structure using both IP technologies and ITU-originated protocols.
In this presentation, we’ll see how this infrastructure is protected and how it can be attacked. We’ll discover the issues with specific telco equipment inside GRX, namely GGSN and SGSN but also now PDN Gateways in LTE and LTE Advanced “Evolved Packet Core”. We will see the implications of this with GTP protocol, DNS infrastructure, AAA servers and core network technologies such as MPLS, IPsec VPNs and their associated routing protocols. These network elements were rarely evaluated for security, and during our engagements with vulnerability analysis, we’ve seen several vulnerabilities that we will be showing in this speech.
We will demo some of the attacks on a simulated “PS Domain” network, that it the IP part of the Telecom Core Network that transports customers’ traffic, and investigate its relationships with legacy SS7, SIGTRAN IP backbones, M2M private corporate VPNs and telecom billing systems. We will also seem how automation enable us to succeed at attacks which are hard to perform and will show how a “sentinel” attack was able to compromise a telecom Core Network during one penetration test.
Telecom security from ss7 to all ip all-open-v3-zeronightsP1Security
Telecom security is way more than SIP-breaking some peripheral PBXs and raking a few thousands of dollars of free calls. From the formerly closed garden of SS7 to new all-IP telecom protocols such as Diameter and LTE protocols, the telecom domain faces now both the challenges of availability -one minute of downtime costs literally millions- and signaling vulnerabilities cutting down entire countries, causing massive frauds and the all new networking protocols. These new telecom protocols are rolled out in IP-centric fashion, with its myriad of standard IP security pitfalls and vulnerabilities, as well as very specific telecom vulnerabilities. The HLR is not only using TCP/IP for OAM and business workflow, but also now being named an HSS, it uses IP-only protocols such as Diameter for its Core Network signaling operations. That means that now telecom are facing new security risks both in term of exposure and threats, with its Core Network being exposed to unsophisticated IP-centered attackers, and the continuous waves of telecom-centered defrauders. In this presentation, we'll demo the new technologies of 3G and LTE networks and how to attack and defend them. We'll also show what kind of exposure one telecom companies, Mobile Network Operators and SS7 providers shows to external attackers.
This presentation was presented at MUM Indonesia at Bali in 2008. Discussed about how to put extra layer of security into your MikroTik Router using Port Knocking mechanism.
APNIC Chief Scientist Geoff Huston presented on TCP and BBR at RIPE 76 in Marseille, France, calling for more research and testing of TCP experiments and scalibility of BBR in the face of important unsolved problems and unknowns.
APNIC Chief Scientist Geoff Huston gives a presentation on Buffers, Buffer Bloat and BBR at NZNOG 2020 in Christchurch, New Zealand, from 28 to 31 January 2020.
A short introductory presentation/video explaining Bandwidth Parts in 5G and why are they needed.
There are two main reasons:
1. Cheaper devices may not want to support the large bandwidth in 5G, that can go up to 400 MHz for FR2 and 100 MHz for FR1
2. A device does not need to monitor the whole of bandwidth for power consumption reduction reasons, here BWP can help too
HTTP/3 is designed to improve in areas where HTTP/2 still has some shortcomings, primarily by changing the transport layer. HTTP/3 is the first major protocol to step away from TCP and instead it uses QUIC.
HTTP/3 is the designated name for the coming next version of the protocol that is currently under development within the QUIC working group in the IETF.
HTTP/3 is designed to improve in areas where HTTP/2 still has some shortcomings, primarily by changing the transport layer. HTTP/3 is the first major protocol to step away from TCP and instead it uses QUIC.
Daniel Stenberg does a presentation about HTTP/3 and QUIC. Why the new protocols are deemed necessary, how they work, how they change how things are sent over the network and what some of the coming deployment challenges will be.
The new 5G unified air interface is being designed to not only vastly enhance mobile broadband performance and efficiency, but also scale to connect the massive Internet of Things and enable new types of services such as mission critical control that require ultra-low latency and new levels of reliability and security. The new design will unify diverse spectrum types and bands, scale from macro deployments to local hotspots and efficiently multiplex the envisioned 5G services across an extreme variation of requirements.
For more information on 5G technologies, use cases and timelines, please visit us at www.qualcomm.com/5G.
A Proxy Server is computer that functions as an intermediary between a web browser (such as Internet
Explorer) and the Internet. Proxy servers help improve web performance by storing a copy of frequently
used webpages. When a browser requests a webpage stored in the proxy server's collection (its cache),
it is provided by the proxy server, which is faster than going to the web. Proxy servers also help improve
security by filtering out some web content and malicious software.
A Proxy Server is a server (a computer system or an application) that acts as an intermediary for
requests from clients seeking resources from other servers.
Webinar topic: BGP on RouterOS7 - Part 1
Presenter: Achmad Mardiansyah & M. Taufik Nurhuda
In this webinar series, How BGP on RouterOS7 works
Please share your feedback or webinar ideas here: http://bit.ly/glcfeedback
Check our schedule for future events: https://www.glcnetworks.com/en/schedule/
Follow our social media for updates: Facebook, Instagram, YouTube Channel, and telegram also discord
Recording available on Youtube
https://youtu.be/CYTHOlY4WU0
GRX is the global private network where telecom network operators exchange GPRS roaming traffic of their users. It’s also used for all M2M networks where roaming is used, and that is the case from some company’s truck fleet management system down to intelligence GPS location spybug tracking system.
GPRS has been there from 2.5G GSM networks to the upcoming LTE Advanced networks, and is now quite widespread technology, along with its attacks. GRX has had a structuring role in the global telecom world at a time where IP dominance was beginning to be acknowledged. Now it has expanded to a lightweight structure using both IP technologies and ITU-originated protocols.
In this presentation, we’ll see how this infrastructure is protected and how it can be attacked. We’ll discover the issues with specific telco equipment inside GRX, namely GGSN and SGSN but also now PDN Gateways in LTE and LTE Advanced “Evolved Packet Core”. We will see the implications of this with GTP protocol, DNS infrastructure, AAA servers and core network technologies such as MPLS, IPsec VPNs and their associated routing protocols. These network elements were rarely evaluated for security, and during our engagements with vulnerability analysis, we’ve seen several vulnerabilities that we will be showing in this speech.
We will demo some of the attacks on a simulated “PS Domain” network, that it the IP part of the Telecom Core Network that transports customers’ traffic, and investigate its relationships with legacy SS7, SIGTRAN IP backbones, M2M private corporate VPNs and telecom billing systems. We will also seem how automation enable us to succeed at attacks which are hard to perform and will show how a “sentinel” attack was able to compromise a telecom Core Network during one penetration test.
Telecom security from ss7 to all ip all-open-v3-zeronightsP1Security
Telecom security is way more than SIP-breaking some peripheral PBXs and raking a few thousands of dollars of free calls. From the formerly closed garden of SS7 to new all-IP telecom protocols such as Diameter and LTE protocols, the telecom domain faces now both the challenges of availability -one minute of downtime costs literally millions- and signaling vulnerabilities cutting down entire countries, causing massive frauds and the all new networking protocols. These new telecom protocols are rolled out in IP-centric fashion, with its myriad of standard IP security pitfalls and vulnerabilities, as well as very specific telecom vulnerabilities. The HLR is not only using TCP/IP for OAM and business workflow, but also now being named an HSS, it uses IP-only protocols such as Diameter for its Core Network signaling operations. That means that now telecom are facing new security risks both in term of exposure and threats, with its Core Network being exposed to unsophisticated IP-centered attackers, and the continuous waves of telecom-centered defrauders. In this presentation, we'll demo the new technologies of 3G and LTE networks and how to attack and defend them. We'll also show what kind of exposure one telecom companies, Mobile Network Operators and SS7 providers shows to external attackers.
This presentation was presented at MUM Indonesia at Bali in 2008. Discussed about how to put extra layer of security into your MikroTik Router using Port Knocking mechanism.
APNIC Chief Scientist Geoff Huston presented on TCP and BBR at RIPE 76 in Marseille, France, calling for more research and testing of TCP experiments and scalibility of BBR in the face of important unsolved problems and unknowns.
APNIC Chief Scientist Geoff Huston gives a presentation on Buffers, Buffer Bloat and BBR at NZNOG 2020 in Christchurch, New Zealand, from 28 to 31 January 2020.
High performance browser networking ch1,2,3Seung-Bum Lee
Presentation material including summary of "High Performance Browser Networking" by Ilya Grigorik. This book includes very good summary of computer network not only for internet browsing but also multimedia streaming.
What is Quality of Service?
-Basic mechanisms
-Leaky and token buckets
-Integrated Services (IntServ)
-Differentiated Services (DiffServ)
-Economics and Social factors facing QoS
-QoS Vs. Over Provisioning
APNIC Foundation, presented by Ellisha Heppner at the PNG DNS Forum 2024APNIC
Ellisha Heppner, Grant Management Lead, presented an update on APNIC Foundation to the PNG DNS Forum held from 6 to 10 May, 2024 in Port Moresby, Papua New Guinea.
Registry Data Accuracy Improvements, presented by Chimi Dorji at SANOG 41 / I...APNIC
Chimi Dorji, Internet Resource Analyst at APNIC, presented on Registry Data Accuracy Improvements at SANOG 41 jointly held with INNOG 7 in Mumbai, India from 25 to 30 April 2024.
APNIC Policy Roundup, presented by Sunny Chendi at the 5th ICANN APAC-TWNIC E...APNIC
Sunny Chendi, Senior Advisor, Membership and Policy at APNIC, presents 'APNIC Policy Roundup' at the 5th ICANN APAC-TWNIC Engagement Forum and 41st TWNIC OPM in Taipei, Taiwan from 23 to 24 April.
DDoS In Oceania and the Pacific, presented by Dave Phelan at NZNOG 2024APNIC
Dave Phelan, Senior Network Analyst/Technical Trainer at APNIC, presents 'DDoS In Oceania and the Pacific' at NZNOG 2024 held in Nelson, New Zealand from 8 to 12 April 2024.
'Future Evolution of the Internet' delivered by Geoff Huston at Everything Op...APNIC
Geoff Huston, Chief Scientist at APNIC deliver keynote presentation on the 'Future Evolution of the Internet' at the Everything Open 2024 conference in Gladstone, Australia from 16 to 18 April 2024.
IP addressing and IPv6, presented by Paul Wilson at IETF 119APNIC
Paul Wilson, Director General of APNIC delivers a presentation on IP addressing and IPv6 to the Policymakers Program during IETF 119 in Brisbane Australia from 16 to 22 March 2024.
draft-harrison-sidrops-manifest-number-01, presented at IETF 119APNIC
Tom Harrison, Product and Delivery Manager at APNIC presents at the Registration Protocols Extensions working group during IETF 119 in Brisbane, Australia from 16-22 March 2024
Benefits of doing Internet peering and running an Internet Exchange (IX) pres...APNIC
Che-Hoo Cheng, Senior Director, Development at APNIC presents on the "Benefits of doing Internet peering and running an Internet Exchange (IX)" at the Communications Regulatory Commission of Mongolia's IPv6, IXP, Datacenter - Policy and Regulation International Trends Forum in Ulaanbaatar, Mongolia on 7 March 2024
APNIC Update and RIR Policies for ccTLDs, presented at APTLD 85APNIC
APNIC Senior Advisor, Membership and Policy, Sunny Chendi presented on APNIC updates and RIR Policies for ccTLDs at APTLD 85 in Goa, India from 19-22 February 2024.
Understanding User Behavior with Google Analytics.pdfSEO Article Boost
Unlocking the full potential of Google Analytics is crucial for understanding and optimizing your website’s performance. This guide dives deep into the essential aspects of Google Analytics, from analyzing traffic sources to understanding user demographics and tracking user engagement.
Traffic Sources Analysis:
Discover where your website traffic originates. By examining the Acquisition section, you can identify whether visitors come from organic search, paid campaigns, direct visits, social media, or referral links. This knowledge helps in refining marketing strategies and optimizing resource allocation.
User Demographics Insights:
Gain a comprehensive view of your audience by exploring demographic data in the Audience section. Understand age, gender, and interests to tailor your marketing strategies effectively. Leverage this information to create personalized content and improve user engagement and conversion rates.
Tracking User Engagement:
Learn how to measure user interaction with your site through key metrics like bounce rate, average session duration, and pages per session. Enhance user experience by analyzing engagement metrics and implementing strategies to keep visitors engaged.
Conversion Rate Optimization:
Understand the importance of conversion rates and how to track them using Google Analytics. Set up Goals, analyze conversion funnels, segment your audience, and employ A/B testing to optimize your website for higher conversions. Utilize ecommerce tracking and multi-channel funnels for a detailed view of your sales performance and marketing channel contributions.
Custom Reports and Dashboards:
Create custom reports and dashboards to visualize and interpret data relevant to your business goals. Use advanced filters, segments, and visualization options to gain deeper insights. Incorporate custom dimensions and metrics for tailored data analysis. Integrate external data sources to enrich your analytics and make well-informed decisions.
This guide is designed to help you harness the power of Google Analytics for making data-driven decisions that enhance website performance and achieve your digital marketing objectives. Whether you are looking to improve SEO, refine your social media strategy, or boost conversion rates, understanding and utilizing Google Analytics is essential for your success.
1.Wireless Communication System_Wireless communication is a broad term that i...JeyaPerumal1
Wireless communication involves the transmission of information over a distance without the help of wires, cables or any other forms of electrical conductors.
Wireless communication is a broad term that incorporates all procedures and forms of connecting and communicating between two or more devices using a wireless signal through wireless communication technologies and devices.
Features of Wireless Communication
The evolution of wireless technology has brought many advancements with its effective features.
The transmitted distance can be anywhere between a few meters (for example, a television's remote control) and thousands of kilometers (for example, radio communication).
Wireless communication can be used for cellular telephony, wireless access to the internet, wireless home networking, and so on.
Meet up Milano 14 _ Axpo Italia_ Migration from Mule3 (On-prem) to.pdfFlorence Consulting
Quattordicesimo Meetup di Milano, tenutosi a Milano il 23 Maggio 2024 dalle ore 17:00 alle ore 18:30 in presenza e da remoto.
Abbiamo parlato di come Axpo Italia S.p.A. ha ridotto il technical debt migrando le proprie APIs da Mule 3.9 a Mule 4.4 passando anche da on-premises a CloudHub 1.0.
2.Cellular Networks_The final stage of connectivity is achieved by segmenting...JeyaPerumal1
A cellular network, frequently referred to as a mobile network, is a type of communication system that enables wireless communication between mobile devices. The final stage of connectivity is achieved by segmenting the comprehensive service area into several compact zones, each called a cell.
Italy Agriculture Equipment Market Outlook to 2027harveenkaur52
Agriculture and Animal Care
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Our Animal care category provides solutions on Animal Healthcare and related products and services, including, animal feed additives, vaccination
2. Networking is all about moving
Data
• The way in which data movement is controlled is a key characteristic of
the network architecture
• The Internet Protocol architecture passed all controls to the end
systems, and treated the network as a passive switching environment
– But that was many years ago, and since then we have seen the deployment of
active middleware in networks and control traffic flows
• All this is changing again as we see a what could well be a new
generation of flow control algorithms being adopted in the Internet
• Lets look at one of the more interesting initiatives: Bottleneck
Bandwidth and Round-Trip Time (BBR)
2
3. Let’s talk about speed
• How fast can we push a single session to move data
through the network?
• Session speed is the result of a combination of:
• available transmission speeds,
• transmission bit error rate,
• end-to-end latency,
• host buffer size and
• protocol efficiency
– All of these factors are critical
3
4. The Evolution of Speed
1980’s
– TCP rates of Kilobits per second
1990’s
– TCP rates of Megabits per second
2000’s
– TCP rates of Gigabits per second
2010’s
– TCP rates of Gigabits per second
4
80’s 90’s 00’s 10’s
K
M
G
5. Today
• Optical transmission speeds are approaching Terrabit
capacity
• But peak TCP session speeds are not keeping up
• What’s going on?
5
80’s 90’s 00’s 10’s
K
M
G
T
optical
transport
TCP speed
6. TCP
• The Transmission Control Protocol is an end-to-end
protocol that creates a reliable stream protocol from the
underlying IP datagram device
• TCP operates as an adaptive rate control protocol that
attempts to operate fairly and efficiently
7. TCP Design Objectives
To maintain an average flow which is Efficient and Fair
• Efficient:
– Minimise packet loss
– Minimise packet re-ordering
– Do not leave unused path bandwidth on the table!
• Fair:
– Do not crowd out other TCP sessions
– Over time, take an average 1/N of the path capacity when there are N
other TCP sessions sharing the same path
8. It’s a Flow Control process
• Think of this as a multi-
flow fluid dynamics
problem
• Each flow has to gently
exert pressure on the
other flows to signal
them to provide a fair
share of the network,
and be responsive to
the pressure from all
other flows
9. TCP Control
TCP is an ACK Pacing protocol
Data sending rate is matched to the
ACK arrival rate
10. TCP Control
ACK pacing protocols relate to a past network state, not
necessarily the current network state
– The ACK signal shows the rate of data that left the network at the
receiver that occurred at ½ RTT back in time
– So if there is data loss in the forward path, the ACK signal of that loss
is already at least ½ RTT old!
• So TCP should react quickly to ‘bad’ news
– If there is no data loss, that is also old news
• So TCP should react conservatively to ‘good’ news
11. “Classic TCP” – TCP Reno
• Additive Increase Multiplicative Decrease (AIMD)
– While there is no packet loss, increase the sending rate by one
segment (MSS) each RTT interval
– If there is packet loss decrease the sending rate by 50% over the
next RTT Interval
• Start Up
– Each RTT interval, double the sending rate
– We call this “slow start” – probably because its anything but slow!!!
12. Idealised TCP Reno
Time
Slow Start
Rate Doubles
each RTT
Interval
Congestion Avoidance
Rate increases by 1 MSS per RTT
Rate halves on Packet Loss
Notification of Packet Loss
via Duplicate ACKs causes
RENO to halve its sending
rate
13. TCP RENO and Idealized Queue
Behaviour
Total Queue Capacity
(Onset of Packet Loss)
Link Capacity Capacity
(Onset of Queuing)
Network Buffers Fill
Network Buffers Drain
14. Reno is too slow
• TCP Reno tries to oscillate between sending rates R and 2R that
span the actual link capacity
• It increases its sending rate slowly so it’s really lousy when trying
to run at very high speed over long delay networks
• It over-corrects on loss and leaves available path capacity idle
– 10Gbps rates over 100ms RTT demands a packet loss rate of less than
0.000003%
– An average 1% loss rate over a 100ms RTT can’t operate faster than
3Mbps
15. Faster than Reno?
• Can we make TCP faster and more efficient by changing
the way in which the sending rate is inflated?
• Of course!
16. Refinements to RENO
• There have been many efforts to alter RENO’s flow control
algorithm
• In a loss-based AIMD control system the essential parameters
are the manner of rate increase and the manner of loss-based
decrease
– For example:
MulTCP behaves as it it were N simultaneous TCP sessions: i.e. increase by N segments
each RTT and rate drop by 1/N upon packet loss
• What about varying the manner of rate increase away from AI?
17. Enter CUBIC
• CUBIC is designed to be useful for high speed sessions while still
being ‘fair’ to other sessions and also efficient even at lower speeds
• Rather than probe in a linear manner for the sending rate that triggers
packet loss, CUBIC uses a non-linear (cubic) search algorithm
18. CUBIC and Queue formation
Total Queue Capacity
(Onset of Packet Loss)
Link Capacity Capacity
(Onset of Queuing)
Network Buffers Fill
Network Buffers Drain
19. CUBIC assessment
• Can react quickly to available capacity in the network
• Tends to sit for extended periods in the phase of queue
formation
• Can react efficiently to long fat pipes and rapidly scale up
the sending rate
• Operates in a manner that tends to exacerbate ‘buffer bloat’
conditions
20. Can we do even better?
• Lets look at the model of the network once more, and observe that there
are three ‘states’ of flow management in this network:
– Under-Utilised – where the flow rate is below the link capacity and no queues form
– Over-Utilised – where the flow rate is greater that the link capacity and queues form
– Saturated – where the queue is filled and packet loss occurs
• Loss-based control systems probe upward to the Saturated point, and back
off quickly to what they guess is the Under-Utilised state in order to the let
the queues drain
• But the optimal operational point for any flow is at the point of state change
from Under to Over-utilised, not at the Saturated point
21. RTT and Delivery Rate with Queuing
Under-Utilised Over-Utilised Saturated
22. How to detect the onset of
queuing?
• By carefully measuring the Round Trip Time!
23. BBR Design Principles
• Probe the path capacity only intermittently
• Probe the path capacity by increasing the sending rate for a short
interval and then drop the rate to drain the queue:
– If the RTT of the probe equals the RTT of the previous state then there is
available path bandwidth that could be utilised
– If the RTT of the probe rises then the path is likely to be at the onset of
queuing and no further path bandwidth is available
• Do not alter the path bandwidth estimate in response to packet loss
• Pace the sending packets to avoid the need for network buffer rate
adaptation
25. BBR Politeness?
• BBR will probably not constantly pull back when
simultaneous loss-based protocols exert pressure on the
path’s queues
• BBR tries to make minimal demands on the queue size,
and does not rely on a large dynamic range of queue
occupancy during a flow
26. From Theory to Practice
• Lets use BBR in the wild
• I’m using iperf3 on Linux platforms (Linode)
– The platforms are dedicated to these tests
• It’s the Internet
– The networks paths vary between tests
– The cross traffic is highly variable
– No measurement is repeatable to a fine level of detail
28. Wow!
• That was BRUTAL!
• As soon as BBR started up it collided with CUBIC, and BBR
startup placed pressure on CUBIC such that CUBIC’s
congestion window was reduced close to zero
• At this stage CUBIC’s efforts to restart its congestion
window appear to collide with BBR’s congestion control
model, so CUBIC remains suppressed
– The inference is that BBR appears to be operating in steady state
with an ability to crowd out CUBIC
29. BBR vs Cubic – second attempt
Same two endpoints, same
network path across the public
Internet
Using a long delay path AU to
Germany via the US
30. BBR vs Cubic
BBR(1)starts
Cubicstarts
BBR(2)starts
Cubicends
BBR(2)ends
The Internet is capable of
offering a 400Mbps capacity
path on demand!
In this case BBR is apparently
operating with filled queues,
and this crowds out CUBIC
BBR does not compete well
with itself, and the two sessions
oscillate in getting the majority
share of available path capacity
31. BBR and Loss
Recovery
31
Packet loss causes
retransmission that
appears to occur in
addition to the stable link
capacity model used by
BBR.
Once loss is reduced, BBR
maintains a more
consistent sending model
32. Parallel
BBR
Streams
32
We used 50 parallel BBR
streams between the
same two endpoints
(200ms RTT)
In this larger setup the
majority of sessions
managed to equilibrate
between each other and
evenly share the path
bandwidth
33. So what can we say about BBR?
It’s “interesting” in so many ways:
– It’s a move away from the more common loss-based flow control
protocols
– It looks like it will operate very efficiently in a high-speed small-buffer
world
• High speed small buffer switching chips are far cheaper, but loss-based TCP
reacts really badly to small buffers by capping its flow rate
– It will operate efficiently over ECMP paths, as it is relatively impervious to
packet re-ordering
– It also looks as if it will operate efficiently in rate policed environments
– Unlike AIMD systems, it will scale from Kbps to Gbps over long delay
paths very efficiently
– It resists the conventional network-based traffic control mechanisms
34. Why use BBR?
• Because it achieves
• Its incredibly efficient
• It makes minimal demands on network buffer capacity
• It’s fast!
35. Why not use BBR?
• Because it over achieves!
• The classic question for many Internet technologies is scaling
– “what if everyone does it?”
– BBR is not a scalable approach in competition with loss-based flows
– It works so well while it is used by just a few users, some of the time
– But when it is active, BBR has the ability to slaughter concurrent
loss-based flows
– Which sends all the wrong signals to the TCP ecosystem
• The loss-based flows convert to BBR to compete on equal terms
• The network is then a BBR vs BBR environment, which is unstable
36. Is this BBR experiment a failure?
Is it just too ‘greedy’ and too ‘insensitive’ to other flows to be
allowed out on the Internet to play?
– Many networks have been provisioned as a response to the
aggregate behaviours of loss-based TCP congestion control
– BBR changes all those assumptions, and could potentially push
many networks into sustained instability
– We cannot use the conventional network control mechanisms to
regulate BBR flows
• Selective packet drop just won’t create back pressure on the flow
37. Is BBR an outstanding success?
• We can’t achieve speed if we need also large high speed buffers
in network routers
– Loss-based flow-control systems have a sloppy control loop that is
always ½ RTT late
– Small buffers in the switches exacerbate this problem
• We can use small buffers in switches if we use flow control
systems that are sensitive to the onset of queue formation (rather
than being sensitive to packet loss resulting from a full queue)
• BBR points to an approach that does not require large buffer
pools in switches
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38. Where now?
BBR 2.0
– Alter BBR’s ‘sensitivity’ to loss rates, so that it does not persist with an
internal bandwidth delay product (BDP) that exceeds the uncongested BDP
This measure would moderate BBR 1.0’s ability to operate for extended periods with
very high loss levels
– Improve the dynamic sharing fairness by moderating the Bandwidth Delay
Product by using an estimated ‘fair’ proportion of the path BDP
– Accommodate the signal distortion caused by ACK stretching middleware
– Place an upper bound on the volume of in-flight data
– Alter the +/- 25% probe factors dynamically (i.e. allow this to be less than
25% overload)
39. The new Network Architecture
• We are seeing a shift in end systems to assert edge-centric
control and hide from network-level active middleware in
the Internet
• QUIC and BBR are instances of a recent push back from
the network-level QoS bandwidth control mechanisms, and
result in greater levels of autonomous control being passed
back to the end hosts
• For better or worse!
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40. What is all this telling us?
• The Internet still contains a large set of important unsolved
problems
• Moving large data sets over high speed networks requires a
different approach to what we are doing today
• BBR seems to be a step in an interesting direction,
particularly for very high speed networking
• But it still calls for more research and more testing at scale
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