Transcript Scalable Architecture for Providing Per-flow Bandwidth Guarantees Dr. Vasil Hnatyshin Computer Science Department Rowan University 11/7/2015 Rowan University Vasil Y.

Scalable Architecture for
Providing Per-flow Bandwidth
Guarantees
Dr. Vasil Hnatyshin
Computer Science Department
Rowan University
11/7/2015
Rowan University
Vasil Y. Hnatyshin
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Outline
Quality of Service (QoS), What is it?
Providing QoS in the Internet.


Integrated Services
Differentiated Service
Bandwidth Distribution Scheme (BDS)
BDS Research Projects





Influence of BDS on TCP traffic
Fair bandwidth distribution using BDS
BDS for DiffServ provisioning
BDS for inter-domain traffic
BDS for mobile environment
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Rowan University
Vasil Y. Hnatyshin
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Introduction to QoS
QoS, What is it?

QoS is a quality of service received by an
application (e.g. perceived by a user of an
application).
Why do we care?


Internet supports only best-effort service
Emerging and existing applications are often
time-sensitive, delay-sensitive, jitter-sensitive or
have other importance requirements which are not
supported by best-effort Internet
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Outline
Quality of Service (QoS), What is it?
Providing QoS in the Internet.


Integrated Services
Differentiated Service
Bandwidth Distribution Scheme (BDS)
BDS Research Projects





Influence of BDS on TCP traffic
Fair bandwidth distribution using BDS
BDS for DiffServ provisioning
BDS for inter-domain traffic
BDS for mobile environment
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Rowan University
Vasil Y. Hnatyshin
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Integrated Services
Simplified Idea: for each newly
admitted flow reserve network
resources at each node on the flow’s
path from source to destination.
Uses per-flow resource reservation
protocol called resource
reservation protocol (RSVP).
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IntServ Example
Internet
Widener
Core1
Core 3
ISP 3
ISP 1
ISP 2
ISP 4
Core 2
Rowan
FTP connection from
Rowan to CNN
Video conference call
from Rowan to CNN
Allocated resources
for corresponding
connections
FTP connection from
Widener to CNN
Video conference call
from Widener to CNN
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Summary:
Integrated Services
Advantages:
Capable of supporting service
requirements of individual flows.
Supports variety of services.
Disadvantages:
Does not scale well to large networks.
Potential waste of resources
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Differentiated Services
Goal: Provide scalable QoS.
DiffServ Implementation:




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Establishes a few classes/aggregates
Classifies arriving traffic into one of predefined classes.
Packets are differentiated based on the
DSCP marking set in the IP header.
Core routers treat arriving traffic based
on the packet’s class.
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Network Architecture
Network Domain
Core 1
The Internet
Network
Domain
Network
Domain
Core 2
Edge B
Edge A
Edge C
Core 3
Edge D
Network
Domain
Network
Domain
Network
Domain
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DiffServ Scalability
Edge Routers:
Network Domain
Core 1
Edge B
Edge A
Edge C
Core 2
Core 3
Edge D
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Rowan University
• Maintain all per-flow
information via SLA
• Perform traffic classification
• Mark arriving packets
Core Routers:
• Maintain only class
information
• Treat arriving traffic based
on the DSCP marking
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DiffServ Example
Internet
Widener
Core1
Core 3
ISP 3
ISP 1
ISP 2
ISP 4
Core 2
Rowan
FTP connection from
Rowan to CNN
Video conference call
from Rowan to CNN
DS Class A
DS Class B
FTP connection from
Widener to CNN
Video conference call
from Widener to CNN
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DiffServ vs. IntServ
Integrated Services Model
 Supports per-flow QoS
 Not Scalable
 Potential Waste of Resources
Differentiated Services Architecture
 Scalable
 Provides only per-aggregate QoS
 Static per-class resource allocation which may
lead to violation of user requirements
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Outline
Quality of Service (QoS), What is it?
Providing QoS in the Internet.


Integrated Services
Differentiated Service
Bandwidth Distribution Scheme (BDS)
BDS Research Projects





Influence of BDS on TCP traffic
Fair bandwidth distribution using BDS
BDS for DiffServ provisioning
BDS for inter-domain traffic
BDS for mobile environment
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Goals of the BDS
Architecture
Scalable
Per-flow QoS
Fairness
Congestion Control
No service violation
Dynamic Resource
Allocation
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The BDS Architecture
RDF
Protocol
Resource
Management
Specifications
and Definitions
Admission
Control
Resource
Allocation
Network
Architecture
Flow
Requirements
Definitions of
Fairness
Scalable
Per-flow QoS
Fairness
Congestion Control
No service violation
Dynamic Resource Allocation
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Network Architecture
Network Domain
Core 1
The Internet
Network
Domain
Network
Domain
Core 2
Edge B
Edge A
Edge C
Core 3
Edge D
Network
Domain
Network
Domain
Network
Domain
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Flow Requirements
Flow Specification:
Requested Bandwidth Range (RBR)
[Min Rate, Max Rate] = [b f , B f ]
Aggregate bottleneck RBR
bBk 
f
b

BBk 
f FBk
f
B

f FBk
Aggregate RBR on interface k
b 
k
b
f F
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f
Bk 
k
Rowan University
f
B

f F k
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Flow Requirements
Aggregate bottleneck RBR vs. Aggregate RBR on interface
Flow 1: [4, 16]
Edge 1
Flow 2: [2, 8]
Core 1
Core 3
Edge 3
Edge 4
Edge 2
Core 2
Flow 3: [3, 12]
Core 1
Core 3
Core 2
Edge 4
Flow 1: [4, 16]
Flow 3: [3, 12]
Flow 2: [2, 8]
Flow 2: [2, 8]
Aggr. RBR on “Core 1 – Core 3” = [6, 24]
BDS Capacity = 18
Aggr. RBR on “Core 2 – Edge 4” = [5, 20]
BDS Capacity = 18
Aggr. bottleneck RBR = [6, 24]
BDS Bottleneck Capacity = 18
Aggr. bottleneck RBR = [3, 12]
BDS Bottleneck Capacity = 18 – Rate(Flow 2)
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Definition of Fairness
Bottleneck Capacity
CBk  C k 
f
k
k
R

C

R

NB
k
f FNB
Proportional Fairness
f
bf
k b
FS  b  (C  b ) k  C B k
bB
bb
k
f
f
k
B
k
B
Maximizing Utility Fairness

FS  b  C  b
k
f
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f
k
B
Rowan University
k
B

Bf bf
BBk  bBk
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Admission Control
Admission control test:
b 
f
k
b

C

k  P
f F k
 -- A new flow
P -- A path of a flow
f -- A flow
k -- A link
C k -- Capacity of link k
F k -- A set of flows that
travel through link k
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Resource Allocation
The value of Bottleneck Capacity is not readily available
in the network, instead we use the value of available
capacity on the link as follows:
f
f
b
b
FS kf  b f  (C k  b k ) k  C k k
b
b
Bf bf
FS  b  C  b
Bk  bk
To avoid resource underutilization, we employ a “waterfilling” technique: increase allocated rates of individual
k
f
f

k
k

flows as long as the bottleneck link is not fully utilized.
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Resource Allocation
Core 1
Core 3
Core 2
Edge 4
Flow 1: [4, 16]
Flow 3: [3, 12]
Flow 2: [2, 8]
Flow 2: [2, 8]
Aggr. RBR on “Core 1 – Core 3” = [6, 24]
BDS Capacity = 18
Rate (Flow 1) = 18 * (4/6) = 12
Rate (Flow 2) = 18 * (2/6)= 6
Link Utilization = (12 +6)/18 = 100%
Aggr. RBR on “Core 2 – Edge 4” = [5, 20]
BDS Capacity = 18
Rate(Flow 3) = 18 * 3 / 5 =10.8
Link Utilization = (10.8 +6)/18 = 93.3%
Aggr. bottleneck RBR = [6, 24]
BDS Bottleneck Capacity = 18
Rate (Flow 1) = 18 * (4/6) = 12
Rate (Flow 2) = 18 * (2/6)= 6
Link Utilization = (12 +6)/18 = 100%
Aggr. bottleneck RBR = [3, 12]
BDS Bottleneck Capacity = 12
Rate(Flow 3) = 12 * 3/3 = 12
Link Utilization = (12 +6)/18 = 100%
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The RBR Distribution and
Feedback (RDF) Protocol
Purpose:

Distribute the Aggregate RBR among the nodes in the network.
Path Probing Phase:

Edge routers periodically probe the network to discover
the route changes (e.g. aggregate RBR, excess
bandwidth).
Update Phase:

Edge nodes notify the core routers about the change of
the aggregate RBR due to flow activation or termination.
Notification Phase:

Core routers notify the edge nodes about congestion.
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RDF Protocol
Network Domain
Core 1
Core 3
Edge 3
A
B
Edge 1
Edge 4
C
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Edge 2
Rowan University
Core 2
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The RDF Protocol Example
Flow F2 requests to enter
the network at Edge 2 to
travel to Edge 5
Edge 5
F2
Edge 1 CN
F1
1. Initiates the Path Probing Phase Probe Reply
F2
2. Updates Local Data Structures
3. Performs Admission Control Test
4. Computes Allocated Rate of F2
5. Initiates the RBR Update Phase
6. Allows F2 to enter the network
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Rowan University
Probe
C1
C2
C3
Edge 6
CN
F1
Edge 2
Edge 3
Edge 4
Core Router C1 discovers
that link C1-C2 is congested
1. C1 initiates the Notification Phase.
2. Edge 1 and Edge 2 adjust allocated
rates of F1 and F2 to eliminate
congestion.
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List of BDS Publications
1.
V. Hnatyshin and A.S. Sethi, "Estimation Based Load Distribution in the Internet," accepted
for publication The International Journal of Computer and Telecommunications
Networking Computer Networks and ISDN Systems (Elsevier).
2.
V. Hnatyshin and A.S. Sethi, “Scalable Architecture for Providing Per-flow Bandwidth
Guarantees,” Proc. of CIIT ’04, St. Thomas, VI, November 2004.
3.
V. Hnatyshin and A.S. Sethi, "Optimization of the Bandwidth Distribution Scheme for Handling
Topology Changes," Proc. IPCCC'04, Phoenix, AZ, April 2004.
4.
V. Hnatyshin and A.S. Sethi, "Reducing load distribution overhead with message aggregation,"
Proc. IPCCC'03, Phoenix, AZ, April 2003.
5.
V. Hnatyshin and A.S. Sethi, “Fair and Scalable Load Distribution in the Internet,” Proc. 3rd
International Conference on Internet Computing, Las Vegas, NV (June 2002).
6.
V. Hnatyshin and A.S. Sethi, “Achieving Fair and Predictable Service Differentiation Through
Traffic Degradation Policies,” Proc. SPIE QoS 2001, Conference on Quality of Service over NextGeneration Data Networks, Denver, CO (Aug. 2001).
7.
V. Hnatyshin and A.S. Sethi, “Avoiding Congestion Through Dynamic Load Control,” Proc.
ITCom-2001, SPIE's International Symposium on The Convergence of Information Technologies
and Communications, Denver, CO (Aug. 2001), pp. 309-323.
8.
V. Hnatyshin and A.S. Sethi, "Bandwidth Distribution Scheme for Dynamic, Scalable, and Fair
Allocation of Bandwidth," submitted for publication in Computer Networks journal
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Outline
Quality of Service (QoS), What is it?
Providing QoS in the Internet.


Integrated Services
Differentiated Service
Bandwidth Distribution Scheme (BDS)
BDS Research Projects





Influence of BDS on TCP traffic
Fair bandwidth distribution using BDS
BDS for Differentiated Services provisioning
BDS for inter-domain traffic
BDS for mobile environment
11/7/2015
Rowan University
Vasil Y. Hnatyshin
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BDS Implementation
Two students are working on
implementation of BDS using OPNET
Modeler software:
Shaun M. Mazzatenta
 Frank J. Genua
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BDS Implementation
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Influence of BDS on TCP traffic
BDS and TCP Properties:


The BDS discards all out-of-profile packets (e.g. the packets
that arrive at the rate higher than the rate allocated to the
flow).
TCP treats packet loss as an indication of severe
congestion.
Problem:

What effects, if any, does the BDS out-of-profile packet
treatment policy (e.g. packet drop) has on TCP?
Possible venues for research:

Do not drop out-of-profile packets, instead:
 Shape (e.g. delay) the out-of-profile packets.
 Send an indication to TCP to slow down misbehaving flows.
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Fair Distribution of Excess
Bandwidth with BDS
BDS properties:


BDS resource distribution may leave links underutilized.
Excess bandwidth is distributed fairly among individual flows
based on results of periodic probing.
Problem:


How FAIR is the BDS excess bandwidth distribution?
Is it Min-Max or Proportionally fair?
Possible venues for research:



Examine fairness of the BDS excess bandwidth distribution
through simulation.
Create a mathematical model to prove/disprove fairness of the
BDS excess bandwidth distribution.
Modify/ Improve/ Update the excess bandwidth distribution of
the BDS approach.
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BDS for DiffServ provisioning
Differentiated Services Properties:




DiffServ relies on static per-class resource allocation.
Current solution uses Bandwidth Brokers (BB).
The BB is a centralized node(s) that contains
complete information about the network domain.
The BB monitors traffic patterns and statically
adjusts per-class resource allocation.
IDEA and Venues for Research:

Examine if it is possible to use the BDS approach for
dynamic bandwidth allocation among DiffServ
classes based on their resource usage or resource
requests?
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Future BDS Extensions
BDS Properties:


The BDS works only within confines of a single
network domain.
The BDS works only within the wired networks.
Venues for Research:


Is it possible to extend the BDS framework to
multi-domain environment? How?
Is it possible to extend BDS framework to mobile
environment? How?
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Summary
The BDS architecture consists of:



The admission control
The resource management mechanism
The RDF protocol.
The BDS provides:


Scalable architecture
Supports per-flow QoS services




Bandwidth guarantees
Fair excess bandwidth distribution
Congestion Control
Dynamic per-flow Bandwidth allocation
There is still plenty of research to be done!
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Conclusions
Q: How a student majoring in Computer Science can join or
start working on a research project?
A: Talk to faculty at Computer Science Department.
Possible Scenarios: a student comes to my office and tells me
that he/she wants to do research in:
Computer Networks:
Quality of Service
Internet Routing and BGP
Mobile and Wireless Networks
Network Security
Others
Other Areas of Science:
Robotics
Theory and AI
Operating Systems
Computer Organization
Graphics and Visualization
Others
 Underwater basket weaving
 Others
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Implementation
Issues: Network Edges
Flow SLA
SLA Table
Data
Destination
MIN Requested Rate
Source Destination
MAX Requested Rate
Source
…
…
…
Source Destination
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Data
Rowan University
Estimated Arrival Rate
Allocated Rate
Data
…
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Implementation
Issues: Network Edges
Admission
Control
Resource
Management
New Flows
Conforming
packets
Traffic
Classifier
Existing Flows
Traffic
Shaper
Unprocessed
packets
Non-Conforming
packets
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Rowan University
Packet
Dropper
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Implementation
Issues: Network Edges
Flow List
SLA Table
Path Table
Source
Destination
…
Source
Destination
…
Egress
…
…
Source
Complete
Path
…
Data
…
Destination
Data
IP Address
Data
Link Capacity
IP Address
Data
IP Address
Data
Arrival Rate
Aggregate RBR
…
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…
Data
Rowan University
Path List
…
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Implementation
Issues: Network Edges
Interfaces Table
IP Address
Data
IP Address
Data
IP Address
Data
…
Link Capacity
Arrival Rate
Aggregate RBR
Edge Nodes List
…
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BDS Implementation
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Spotlight on Faculty Research.
This year the Computer Science Department will be holding a series of seminars to
highlight research in the field. Please make an effort to attend these seminars, and
don't be discouraged if a topic is one that you may not be familiar with. Snacks will also
be served! The first presentation is scheduled for Wednesday, November 17th at
10:50 am in Robinson 101A.
Supporting per-flow QoS using the
Bandwidth Distribution Scheme.
By Dr. Vasil Y. Hnatyshin
Date:
Time:
Location:
11/7/2015
Wednesday, November 17th
10:50 am
Robinson building, Room 101 A.
Rowan University
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Summary of the RDF Protocol
Phase
Name
Path Probing
RBR Update
Notification
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Direction Initiate
of info flow
by
Cause of
Initiation
Edge-to-Core
Core-to-Edge
Edge
Routers
Periodic
Edge-to-Core
Edge
Routers
Flow Activation or
Flow Termination
Core-to-Edge
Core
Routers
Congestion
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Summary of the RDF Protocol
Phase
Name
Updates Data
Structures
Carries
Information
Path Probing
• Path Table (Edges)
• Link Table (Edges)
• Interfaces Table (Core)
RBR Update
• Interfaces Table (Core) RBR Change values
Notification
• Path Table (Edges)
• Link Table (Edges)
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Rowan University
Edge node ID
Path Characteristics
Congested Link Info
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