Investigating the Prefix-level Characteristics A
Case Study in an IPv6 Network
Authors:
Fuliang Li, Tian Pan, Jiahai Yang,
Changqing An, Xingwei Wang, Jianping Wu.
Publisher:
2015 International Conference on Computing,
Networking and Communication (ICNC)
Presenter:
Chun-Yu, Li
Date:
2015/10/14
Department of Computer Science and Information Engineering,
National Cheng Kung University, Tainan, Taiwan, R.O.C.
Outline




Introduction
•
•
Exhausting of IPv4
Main Investigation
Studied Network and Datasets
Assignment and Activity of IPv6 Prefixes
•
•
Prefix Assignment
Prefix Activity
Prefix-level Characteristic of CERNET2
•
•
•
•
Prefix Activity Observed from Traffic
Packet and Traffic Distribution across Prefixes
Relationships among Address, Prefixes and Packets
Prefixes Distribution across Different Timescales
Computer & Internet Architecture Lab
CSIE NCKU
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Exhausting of IPv4 (1/1)



Internet Assigned Numbers Authority (IANA)
announced in February 2011 that the last of the
world’s remaining IPv4 blocks had been assigned to
the Regional Internet Registries (RIR).
On April 15, 2011 the Asia Pacific Region claimed it
has reached the last block of IPv4 addresses in its
available pool.
As IPv6 has much larger address space than IPv4,
understanding the characteristics of IPv6 prefixes is
of great benefit to guide the efficient IPv6 routing
cache design.
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Outline




Introduction
•
•
Exhausting of IPv4
Main Investigation
Studied Network and Datasets
Assignment and Activity of IPv6 Prefixes
•
•
Prefix Assignment
Prefix Activity
Prefix-level Characteristic of CERNET2
•
•
•
•
Prefix Activity Observed from Traffic
Packet and Traffic Distribution across Prefixes
Relationships among Address, Prefixes and Packets
Prefixes Distribution across Different Timescales
Computer & Internet Architecture Lab
CSIE NCKU
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Main Investigation (1/1)



We launch a full-scale statistics of IPv6 prefixes from
two aspects, i.e., assignment and activity.
We analyze the prefix-level characteristics based on
the traces of an IPv6 network.
We conduct a case study on prefix related
characteristics in an IPv6 network.
Computer & Internet Architecture Lab
CSIE NCKU
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Outline




Introduction
•
•
Exhausting of IPv4
Main Investigation
Studied Network and Datasets
Assignment and Activity of IPv6 Prefixes
•
•
Prefix Assignment
Prefix Activity
Prefix-level Characteristic of CERNET2
•
•
•
•
Prefix Activity Observed from Traffic
Packet and Traffic Distribution across Prefixes
Relationships among Address, Prefixes and Packets
Prefixes Distribution across Different Timescales
Computer & Internet Architecture Lab
CSIE NCKU
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Studied Network and Datasets (1/2)


The datasets are collected from the link
connecting CERNET2 with CNGI-6IX.
The bandwidth of the link is 10Gbps.
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Studied Network and Datasets (2/2)

CERNET2
• It is a nation-wide pure IPv6 backbone network.
• It focuses on solving technical challenges during IPv6
deployment, overcoming difficulties in the operation
and management of IPv6 networks.

CNGI-6IX (China Next Generation Internet)
• CERNET2 interconnects to domestic CNGI backbones
and international research networks through the
exchange point of CNGI-6IX.
Computer & Internet Architecture Lab
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Outline




Introduction
•
•
Exhausting of IPv4
Main Investigation
Studied Network and Datasets
Assignment and Activity of IPv6 Prefixes
•
•
Prefix Assignment
Prefix Activity
Prefix-level Characteristic of CERNET2
•
•
•
•
Prefix Activity Observed from Traffic
Packet and Traffic Distribution across Prefixes
Relationships among Address, Prefixes and Packets
Prefixes Distribution across Different Timescales
Computer & Internet Architecture Lab
CSIE NCKU
9
Prefix Assignment (1/2)

IPv6 prefixes allocated to the five RIRs (Regional Internet
Registry) present obvious growth during 2011 – 2013.
75%
551%
more coverage area
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Prefix Assignment (2/2)

We also find that prefixes of /32 account for 71% and
67.2% of the total assigned prefixes in 2011 and 2013
respectively, while the ratios are 19.1% and 20.4% for
prefixes of /48.
Computer & Internet Architecture Lab
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Outline




Introduction
•
•
Exhausting of IPv4
Main Investigation
Studied Network and Datasets
Assignment and Activity of IPv6 Prefixes
•
•
Prefix Assignment
Prefix Activity
Prefix-level Characteristic of CERNET2
•
•
•
•
Prefix Activity Observed from Traffic
Packet and Traffic Distribution across Prefixes
Relationships among Address, Prefixes and Packets
Prefixes Distribution across Different Timescales
Computer & Internet Architecture Lab
CSIE NCKU
12
Prefix Activity (1/2)


We gather RIBs (Routing Information Base) from two
observation points - CERNET2 on Nov 15, 2013 and
University of Oregon Route Views project on Nov 20,
2013.
Active prefixes in the closed interval of [32, 48] also
account for most of the active prefixes (96.5% and 93.1%
of the two observation points respectively).
Computer & Internet Architecture Lab
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Prefix Activity (2/2)




The UPDs (BPG update messages) are collected from the
border routers of CERNET2 in one-week scale.
Only 56.13% of the total prefixes contribute UPDs.
Prefixes whose lengths are within the range of [32, 48]
contribute 96.5% of the total update messages.
Prefixes in the closed interval of [32, 48] account for 97%
of the total withdraw messages.
4103763 prefixes/day
47 prefixes/second
(One-week scale)
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Outline




Introduction
•
•
Exhausting of IPv4
Main Investigation
Studied Network and Datasets
Assignment and Activity of IPv6 Prefixes
•
•
Prefix Assignment
Prefix Activity
Prefix-level Characteristic of CERNET2
•
•
•
•
Prefix Activity Observed from Traffic
Packet and Traffic Distribution across Prefixes
Relationships among Address, Prefixes and Packets
Prefixes Distribution across Different Timescales
Computer & Internet Architecture Lab
CSIE NCKU
15
Prefix Activity Observed from Traffic (1/1)
(Trace of CERNET2)
Computer & Internet Architecture Lab
CSIE NCKU
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Outline




Introduction
•
•
Exhausting of IPv4
Main Investigation
Studied Network and Datasets
Assignment and Activity of IPv6 Prefixes
•
•
Prefix Assignment
Prefix Activity
Prefix-level Characteristic of CERNET2
•
•
•
•
Prefix Activity Observed from Traffic
Packet and Traffic Distribution across Prefixes
Relationships among Address, Prefixes and Packets
Prefixes Distribution across Different Timescales
Computer & Internet Architecture Lab
CSIE NCKU
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Packet and Traffic Distribution across Prefixes (1/2)


The most popular prefix in 2011 and 2013 is
2001:cc0::/32, which accounts for 81.4% and 61.4 % of
the packets respectively.
1% of the active prefixes account for 98.14% of the
packets in 2011, and 97.44% in 2013.
98.14%
97.44%
1%
(Trace of CERNET2)
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CSIE NCKU
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Packet and Traffic Distribution across Prefixes (2/2)


The most popular prefix in 2011 and 2013 is
2001:8000::/20, which contributes 86.78% and 61.72% of
the aggregate traffic respectively.
1% of the active prefixes account for 98.39% of the traffic
in 2011, while the proportion is 97.75% in 2013.
98.89%
97.44%
1%
(Trace of CERNET2)
Computer & Internet Architecture Lab
CSIE NCKU
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Outline




Introduction
•
•
Exhausting of IPv4
Main Investigation
Studied Network and Datasets
Assignment and Activity of IPv6 Prefixes
•
•
Prefix Assignment
Prefix Activity
Prefix-level Characteristic of CERNET2
•
•
•
•
Prefix Activity Observed from Traffic
Packet and Traffic Distribution across Prefixes
Relationships among Address, Prefixes and Packets
Prefixes Distribution across Different Timescales
Computer & Internet Architecture Lab
CSIE NCKU
20
Relationships among Address, Prefixes and Packets (1/2)


1% of the active prefixes account for 60.6% and 71.9%
of the addresses in 2011 and 2013.
When the proportion of the active prefixes reaches
20%, the proportion of the active addresses is more than
90%.
71.9%
60.6%
1%
Computer & Internet Architecture Lab
CSIE NCKU
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Relationships among Address, Prefixes and Packets (2/2)


top 5% users account for 97.4% and 99.2% of the packets
in 2011 and in 2013 respectively.
According to the results, we can infer that a small part of
users contribute most of the packets.
99.2%
5%
Computer & Internet Architecture Lab
CSIE NCKU
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Outline




Introduction
•
•
Exhausting of IPv4
Main Investigation
Studied Network and Datasets
Assignment and Activity of IPv6 Prefixes
•
•
Prefix Assignment
Prefix Activity
Prefix-level Characteristic of CERNET2
•
•
•
•
Prefix Activity Observed from Traffic
Packet and Traffic Distribution across Prefixes
Relationships among Address, Prefixes and Packets
Prefixes Distribution across Different Timescales
Computer & Internet Architecture Lab
CSIE NCKU
23
Prefixes Distribution across Different Timescales (1/3)

The variation of the active prefixes in a period are
often used to estimate how large a cache will be
needed to achieve a given miss rate.
(One minute time interval)
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CSIE NCKU
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Prefixes Distribution across Different Timescales (2/3)

The number of the changed prefixes is often used to
estimate how often the cache should be updated.
(One minute time interval)
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Prefixes Distribution across Different Timescales (3/3)

If the update frequency of the routing system is higher, the
buffer reserved for the worst-case burst updates could be
even smaller.
•
E.g., If the routing cache is updated once an hour and assume that
there are no vanishing prefixes, we should reserve 5184 bytes
(342*16 bytes).
B2011(30)=321
B2011(60)=342
B2011(5)=264
Computer & Internet Architecture Lab
CSIE NCKU
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