An Approach for Efficient, Accurate, and
Timely Estimation of Traffic Matrices
Hongbin Luo, Zhe Chen, Jianbo Cui, Hongke Zhang
Beijing Jiaotong University
The 17th IEEE Global Internet Symposium
April 28, 2014, Toronto
Roadmap
1
2
Motivation
2
Requirements and Implications
3
A Possible Internet Architecture
4
Performance Evaluation
5
Conclusion and Future Work
An Approach for Efficient, Accurate, and Timely Estimation of Traffic Matrices
Beijing Jiaotong University
1. Motivation
What is a traffic matrix (TM)?
A TM describes the traffic volume (packets/ bytes)
between an ingress and egress (IE) node pair in a network.
The traffic matrices are critical inputs to many aspects
of network functions such as traffic engineering,
capacity provisioning, and anomaly detection.
Therefore, network operators desire to obtain accurate
evaluations of the traffic matrices of their networks.
Under the current Internet architecture, however, it is
extremely challenging to accurately, efficiently, and
timely measure the TM between IE node pairs.
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An Approach for Efficient, Accurate, and Timely Estimation of Traffic Matrices
Beijing Jiaotong University
1. Motivation
Why is it extremely challenging?
 First, the TM in many networks is not directly observable.
Instead, it can only be estimated through link load
measurements.
 Second, the collected large amount of per flow/packet
information has to be transported to a centralized location for
correlation. But Correlation:
 is time-consuming: so, TM estimation cannot be timely;
 relies on high-performance servers: TM is not efficient;
 relies on inputs from different nodes that have different
observations: TM is not accurate.
 Third, the TM estimation has to be done at very high speed
since an Internet service provider (ISP) may forward data
packets at a speed of over one Terabits per second (Tbps).
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An Approach for Efficient, Accurate, and Timely Estimation of Traffic Matrices
Beijing Jiaotong University
1. Motivation
In addition, the current Internet faces
other serious issues (such as poor security and
scalability) that cannot be remedied by
incremental changes.
Therefore, in recent years there are
increasing efforts in developing “clean-slate”
redesigns of the Internet architecture, aiming
at rectifying one or more of these problems
through non-incremental changes.
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An Approach for Efficient, Accurate, and Timely Estimation of Traffic Matrices
Beijing Jiaotong University
1. Motivation
So, the problem is:
 Could we design a future Internet
architecture that makes it easy for
network operators to accurately
estimate the traffic matrices of
their networks in an efficient and
timely manner?
6
An Approach for Efficient, Accurate, and Timely Estimation of Traffic Matrices
Beijing Jiaotong University
Roadmap
1
7
Motivation
2
Requirements and Implications
3
A Possible Internet Architecture
4
Performance Evaluation
5
Conclusion and Future Work
An Approach for Efficient, Accurate, and Timely Estimation of Traffic Matrices
Beijing Jiaotong University
2. Requirements and Implications
Requirements for TM estimation
① Accurate estimation: Novel technologies such as
OpenFlow requires that the estimated traffic matrices
are accurate since if otherwise, the controller may make
wrong decisions when computing paths for flows.
② Timely estimation: Network managers can make the
best use of network resources based on its state-ofthe-art network status only when the traffic matrices
are estimated in real time.
③ efficient estimation: We desire that the traffic
estimation is not dependent on computers with strong
computation capability.
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An Approach for Efficient, Accurate, and Timely Estimation of Traffic Matrices
Beijing Jiaotong University
2. Requirements and Implications
Implications of requirements
① Accurate estimation:
Every byte/packet should be accounted.
It is better to use the flow information
observed at the ingress node to estimate
the TM.
② Timely estimation:
TM estimation should be performed
during the packet forwarding process.
③ efficient estimation:
TM estimation should be performed in a
distributed manner, without requiring a
centralized node for correlation.
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An Approach for Efficient, Accurate, and Timely Estimation of Traffic Matrices
The
future
Internet
should make it
possible for an
ingress
node
to
estimate
the
traffic
matrices from
it to the rest
nodes during
its
packet
forwarding
process.
Beijing Jiaotong University
Roadmap
1
10
Motivation
2
Requirements and Implications
3
A Possible Internet Architecture
4
Performance Evaluation
5
Conclusion and Future Work
An Approach for Efficient, Accurate, and Timely Estimation of Traffic Matrices
Beijing Jiaotong University
3. A Possible Internet Architecture
We have proposed a future Internet
architecture called CoLoR, whose basic idea is to
couple service location with inter-domain routing,
but to decouple them from forwarding.
We have also built a prototype and demonstrate
that CoLoR satisfies many requirements of the
future Internet including being information-centric,
encouraging innovation, and providing efficient
support for mobility, multicast, multi-homing, and
middle-boxes.
Below we briefly introduce the basic ideas of
CoLoR.
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An Approach for Efficient, Accurate, and Timely Estimation of Traffic Matrices
Beijing Jiaotong University
3. A Possible Internet Architecture
Basic ideas:
12
I. Using four namespaces:
Service identifiers (SIDs): used to name contents.
They are flat, self-certifying.
Node identifiers (NIDs): used to identify the
identity of network nodes. They are flat, selfcertifying and 128 bits long.
Intra-domain routing locators: used for intradomain routing. Every domain can choose its
preferred intra-domain routing architecture and
routing locators.
Path identifiers (PIDs): used for inter-domain
routing. Two domains can negotiate a set of PIDs, as
long as the PIDs are unique in each domain. PIDs are
not advertised throughout the Internet, but are
Beijing Jiaotong University
An Approach
for Efficient,
Accurate,
and Timely Estimation of Traffic Matrices
local
to the
two
domains.
3. A Possible Internet Architecture
Basic ideas:
II. Using name-based routing for service location.
III.Inter-domain routing for data packet forwarding is
determined during the service location process.
IV. Intra-domain routing may or may not be determined
during the service location process. We leave this for
domains’ local policy.
V. End-to-end data packet forwarding is based on loose
source routing.
While some of the ideas are borrowed from existing
literature, we believe that: one can see further by
standing on the shoulders of giants.
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An Approach for Efficient, Accurate, and Timely Estimation of Traffic Matrices
Beijing Jiaotong University
3. A Possible Internet Architecture
Network topology
D6
R7
R6
R8
R5
D3
D5
R2
R4
R1
D1
14
R10
R9
R11
R2
D2
As the current
Internet, CoLoR
assumes that the
future Internet
will still centered
around domains.
R12
D4
Domains have the
AS-level provider/
customer/peer
relationship.
An Approach for Efficient, Accurate, and Timely Estimation of Traffic Matrices
Beijing Jiaotong University
3. A Possible Internet Architecture
Intra-domain routing
D6
Domain 3 uses MPLS for
intra-domain routing.
R7
R6
R8
Domain 1
uses IPv6
for intradomain
routing.
Domain 4 uses
OpenFlow for
intra-domain
routing.
R5
D3
D5
R2
R4
R1
D1
R10
R9
R11
R2
D2
R12
D4
A domain can freely choose its preferred intra-domain
routing architecture, without considering other domains.
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An Approach for Efficient, Accurate, and Timely Estimation of Traffic Matrices
Beijing Jiaotong University
3. A Possible Internet Architecture
Inter-domain routing
P7
R4
D2
P6
R2
D1
P5
R5
D6
D6
R7
P5
P1
R6
R8
R5
D3
D5
R2
R4
P6
R1
D1
R10
R9
P7
R11
R2
D2
R12
P4
Interdomain
routing
relies on
paths
negotiate
d by two
neighbor
domains.
D4
Nodes in a domain maintains the end point of every
path that connects the domain to a neighboring domain.
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An Approach for Efficient, Accurate, and Timely Estimation of Traffic Matrices
Beijing Jiaotong University
3. A Possible Internet Architecture
Service registration
RM6
Every domain has a logical
resource manager.
D6
R7
P5
The service registration
process is similar to that
in DONA.
R6
R8
RM5
R5
D3
RM3
D5
R2
Content
sources
register SIDs to
their local RMs,
which registers the
SID to their peers
or provider RMs.
17
P1
R4
P6
R1
RM1
D1
R2
R10
R9
P7
R11
R12
RM2
D2
A
An Approach for Efficient, Accurate, and Timely Estimation of Traffic Matrices
P4
D4
RM4
Beijing Jiaotong University
3. A Possible Internet Architecture
Service location and
inter-domain routing
RM6
D6
R7
Users send requests to
their local RMs when
they want a content
represented by an SID.
P5
(iv)
R6
R8
RM5
RM3
D5
R2
RMs forward
requests to
either the
closest copy
of the content,
or their
provider RMs.
P1
R5
D3
P6
(v)
RM1
D1
R2
R10
R9
R4
R1
(iii)
P7
R11
R12
RM2
D2
A
(ii)
P4
(i)
D4
C
RM4
(vi)
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An Approach for Efficient, Accurate, and Timely Estimation of Traffic Matrices
Beijing Jiaotong University
3. A Possible Internet Architecture
Service location and routing
(vi)
SID1
C
P4
P1
P5
P6
(v)
SID1
C
P4
P1
P5
P6
RM6
D6
R7
SID1
C
P4
P1
(iii)
SID1
C
P4
P1
(ii)
SID1
C
P4
(iv)
(i)
SID1
(iv)
R6
D3
R8
RM5
RM3
D5
R2
P6
(v)
RM1
D1
R2
R10
R9
R4
R1
(iii)
P1
R5
C
Every time a RM
forwards a request
to a neighboring RM,
it appends the path
between the two
domains onto the
request.
19
P5
P5
P7
R11
R12
RM2
D2
A
(ii)
P4
(i)
D4
C
RM4
(vi)
An Approach for Efficient, Accurate, and Timely Estimation of Traffic Matrices
Beijing Jiaotong University
3. A Possible Internet Architecture
Packet forwarding
(d)
Intra-domain packet
forwarding is based
on
the
routing
mechanism of each
domain.
Inter-domain packet
forwarding is based
on PIDs that are
determined during
the service location
process.
R1
D1
RM1
(a)
A
(a)
IP1
IP2
(b)
R5
IP1
D3
IP2
(c)
R2
P6
P6
P5
P5
P1
RM3
R4
P4
C
SID1
data
(b)
P6
P5
P1
P4
C
SID1
data
(c)
MPLS LSP1
P5
P1
P4
C
SID1
data
P5
P1
P4
C
SID1
data
(d)
Every time a border router receives an incoming packet, it strips out
the outer most PID in the packet header.
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An Approach for Efficient, Accurate, and Timely Estimation of Traffic Matrices
Beijing Jiaotong University
3. A Possible Internet Architecture
TM estimation in CoLoR
P5
R1
D1
R5
IP1
RM1
D3
RM3
A
P6
IP2
P5
P1
P4
C
R2
SID1
R4
data
P7
R4
D2
P6
R2
D1
P5
R5
D6
Every time an ingress border router receives a packet, it reads the
outermost PID, and looks up its inter-domain routing table. This
way, it knows the egress node of the packet. Accordingly, it simply
adds the bytes of the packet onto the TM from the IR to the ER.
21
An Approach for Efficient, Accurate, and Timely Estimation of Traffic Matrices
Beijing Jiaotong University
Roadmap
1
22
Motivation
2
Requirements and Implications
3
A Possible Internet Architecture
4
Performance Evaluation
5
Conclusion and Future Work
An Approach for Efficient, Accurate, and Timely Estimation of Traffic Matrices
Beijing Jiaotong University
4. Performance evaluation
We have built a prototype to show the accuracy of TM estimation
in CoLoR and that in OpenFlow.
D1
PID1
Domain 5
A
B
PID2
D2
RM/
controller
D3
PID2
C
D
PID4
D4
We estimate the
traffic
matrices
from node A to the
other nodes B, C,
and D, assuming
that node D1 is the
source and nodes
D2, D3, and D4 are
the destinations of
packets.
(c) the network topology of the prototype
While the results are similar, we only report the estimated TM
from node A to node C.
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An Approach for Efficient, Accurate, and Timely Estimation of Traffic Matrices
Beijing Jiaotong University
4. Performance evaluation
The estimated TM from node A to node C
The traffic matrix from node A to node C
4500
4000
The number of bytes
3500
3000
2500
2000
1500
1000
The real traffic matrix
The traffic matrix esimated with CoLoR
The traffic matrix estimated with OpenTM
500
0
0
100
200
300
400
500
600
time (second)
700
800
900
1000
Both CoLoR
and
OpenTM
can
accurately
estimate
the traffic
matrices.
the duration between two consecutive polls in
OpenFlow is shorter than the default value for a
switch to remove a flow entry from its flow table.
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An Approach for Efficient, Accurate, and Timely Estimation of Traffic Matrices
Beijing Jiaotong University
4. Performance evaluation
The estimated TM from node A to node C
The traffic matrix from node A to node C
4500
OpenTM
cannot
accurately
estimate
the traffic
matrices.
But CoLoR
can.
4000
The number of bytes
3500
3000
2500
2000
1500
The real traffic matrix
the traffic matrix estimated with CoLoR
the traffic matrix estimated with OpenTM
1000
500
0
0
100
200
300
400
500
600
time (seconds)
700
800
900
1000
the duration between two consecutive polls in
OpenFlow is larger than the default value for a
switch to remove a flow entry from its flow table.
25
An Approach for Efficient, Accurate, and Timely Estimation of Traffic Matrices
Beijing Jiaotong University
6. Conclusions and Future Work
Conclusions
 we present the requirements for TM estimation and
the corresponding implications on the future Internet
architecture.
 we present a future Internet architecture that makes
it easy to accurately, efficiently, and timely estimate
traffic matrices.
 we describe how to estimate traffic matrices of a
network under the proposed Internet architecture.
 we present numerical results to demonstrate the
performance of the proposed Internet architecture
in estimating traffic matrix.
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An Approach for Efficient, Accurate, and Timely Estimation of Traffic Matrices
Beijing Jiaotong University
6. Conclusions and Future Work
Future Work
 While we have shown that CoLoR makes it possible to
accurately, timely and efficiently estimate traffic
matrices, an important question needs to be answered.
 How an ISP could benefit from accurate, timely and
efficient estimation of traffic matrices? We will
investigate this question in the future.
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An Approach for Efficient, Accurate, and Timely Estimation of Traffic Matrices
Beijing Jiaotong University
Thanks!
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An Approach for Efficient, Accurate, and Timely Estimation of Traffic Matrices
Beijing Jiaotong University