draft-wang-teas-ccdr-04.txt   draft-wang-teas-ccdr-05.txt 
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Internet Draft China Telecom Internet Draft China Telecom
Xiaohong Huang Xiaohong Huang
BUPT BUPT
Caixia Kou Caixia Kou
BUPT BUPT
Lu Huang Lu Huang
China Mobile China Mobile
Penghui Mi Penghui Mi
Tencent Company Tencent Company
Intended status: Experimental Track January 19, 2018 Intended status: Experimental Track January 25, 2018
Expires: July 18, 2018 Expires: July 24, 2018
CCDR Scenario, Simulation and Suggestion CCDR Scenario, Simulation and Suggestion
draft-wang-teas-ccdr-04.txt draft-wang-teas-ccdr-05.txt
Status of this Memo Status of this Memo
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Traditional MPLS-TE solution is mainly used in static network Traditional MPLS-TE solution is mainly used in static network
planning scenario and is difficult to meet the QoS assurance planning scenario and is difficult to meet the QoS assurance
requirements in real-time traffic network. With the emerge of SDN requirements in real-time traffic network. With the emerge of SDN
concept and related technologies, it is possible to simplify the concept and related technologies, it is possible to simplify the
complexity of distributed control protocol, utilize the global view complexity of distributed control protocol, utilize the global view
of network condition, give more efficient solution for traffic of network condition, give more efficient solution for traffic
engineering in various complex scenarios. engineering in various complex scenarios.
Table of Contents Table of Contents
1. Introduction ................................................ 3 1. Introduction ................................................ 2
2. Conventions used in this document............................ 4 2. CCDR Scenarios. ............................................. 3
3. CCDR Scenarios. ............................................. 4 2.1. Qos Assurance for Hybrid Cloud-based Application........ 3
3.1. Qos Assurance for Hybrid Cloud-based Application.........4 2.2. Increase link utilization based on tidal phenomena...... 4
3.2. Increase link utilization based on tidal phenomena...... 5 2.3. Traffic engineering for IDC/MAN asymmetric link......... 5
3.3. Traffic engineering for IDC/MAN asymmetric link......... 6 2.4. Network temporal congestion elimination. ............... 6
3.4. Network temporal congestion elimination. ............... 6 3. CCDR Simulation. ............................................ 6
4. CCDR Simulation. ............................................ 7 3.1. Topology Simulation..................................... 6
4.1. Topology Simulation..................................... 7 3.2. Traffic Matrix Simulation............................... 7
4.2. Traffic Matrix Simulation............................... 7 3.3. CCDR End-to-End Path Optimization ...................... 7
4.3. CCDR End-to-End Path Optimization ...................... 8 3.4. Network temporal congestion elimination ................ 8
4.4. Network temporal congestion elimination ................ 9 4. CCDR Deployment Consideration................................ 9
5. Security Considerations..................................... 10
5. CCDR Deployment Consideration............................... 10 6. IANA Considerations ........................................ 10
6. Security Considerations..................................... 10 7. Conclusions ................................................ 10
7. IANA Considerations ........................................ 10 8. References ................................................. 10
8. Conclusions ................................................ 10 8.1. Normative References................................... 10
9. References ................................................. 10 8.2. Informative References................................. 10
9.1. Normative References................................... 10 9. Contributors: .............................................. 11
9.2. Informative References................................. 11 10. Acknowledgments ........................................... 11
10. Contributors: ............................................. 12
11. Acknowledgments ........................................... 12
1. Introduction 1. Introduction
Internet network is composed mainly tens of thousands of routers that Internet network is composed mainly tens of thousands of routers that
run distributed protocol to exchange the reachability information run distributed protocol to exchange the reachability information
between them. The path for the destination network is mainly between them. The path for the destination network is mainly
calculated and controlled by the traditional IGP protocols. These calculated and controlled by the traditional IGP protocols. These
distributed protocols are robust enough to support the current distributed protocols are robust enough to support the current
evolution of Internet but has some difficulties when the application evolution of Internet but has some difficulties when the application
requires the end-to-end QoS performance, or the service provider requires the end-to-end QoS performance, or the service provider
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provider almost can't make such SLA guarantees upon the real time provider almost can't make such SLA guarantees upon the real time
traffic situation. traffic situation.
This draft gives some scenarios that the centrally control dynamic This draft gives some scenarios that the centrally control dynamic
routing (CCDR) architecture can easily solve, without adding more routing (CCDR) architecture can easily solve, without adding more
extra burdening on the router. It also gives the PCE algorithm extra burdening on the router. It also gives the PCE algorithm
results under the similar topology, traffic pattern and network size results under the similar topology, traffic pattern and network size
to illustrate the applicability of CCDR architecture. Finally, it to illustrate the applicability of CCDR architecture. Finally, it
gives some suggestions for the implementation and deployment of CCDR. gives some suggestions for the implementation and deployment of CCDR.
2. Conventions used in this document 2. CCDR Scenarios.
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
3. CCDR Scenarios.
The following sections describe some scenarios that the CCDR The following sections describe some scenarios that the CCDR
architecture is suitable for deployment. architecture is suitable for deployment.
3.1. Qos Assurance for Hybrid Cloud-based Application. 2.1. Qos Assurance for Hybrid Cloud-based Application.
With the emerge of cloud computing technologies, enterprises are With the emerge of cloud computing technologies, enterprises are
putting more and more services on the public oriented service putting more and more services on the public oriented service
infrastructure, but keep still some core services within their infrastructure, but keep still some core services within their
network. The bandwidth requirements between the private cloud and network. The bandwidth requirements between the private cloud and
the public cloud are occasionally and the background traffic between the public cloud are occasionally and the background traffic between
these two sites varied from time to time. Enterprise cloud these two sites varied from time to time. Enterprise cloud
applications just want to invoke the network capabilities to make applications just want to invoke the network capabilities to make
the end-to-end QoS assurance on demand. Otherwise, the traffic the end-to-end QoS assurance on demand. Otherwise, the traffic
should be controlled by the distributed protocol. should be controlled by the distributed protocol.
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By default, the traffic path between the private cloud site and By default, the traffic path between the private cloud site and
public cloud site will be determined by the distributed control public cloud site will be determined by the distributed control
network. When some applications require the end-to-end QoS assurance, network. When some applications require the end-to-end QoS assurance,
it can send these requirements to PCE, let PCE compute one e2e path it can send these requirements to PCE, let PCE compute one e2e path
which is based on the underlying network topology and the real which is based on the underlying network topology and the real
traffic information, to accommodate the application's bandwidth traffic information, to accommodate the application's bandwidth
requirements. The proposed solution can refer the draft [draft-wang- requirements. The proposed solution can refer the draft [draft-wang-
teas-pce-native-ip]. Section 4 describes the detail simulation teas-pce-native-ip]. Section 4 describes the detail simulation
process and the results. process and the results.
3.2. Increase link utilization based on tidal phenomena. 2.2. Increase link utilization based on tidal phenomena.
Currently, the network topology within MAN is generally in star mode Currently, the network topology within MAN is generally in star mode
as illustrated in Fig.2, with the different devices connect as illustrated in Fig.2, with the different devices connect
different customer types. The traffic pattern of these customers different customer types. The traffic pattern of these customers
demonstrates some tidal phenomena that the links between the CR/BRAS demonstrates some tidal phenomena that the links between the CR/BRAS
and CR/SR will experience congestion in different periods because and CR/SR will experience congestion in different periods because
the subscribers under BRAS often use the network at night and the the subscribers under BRAS often use the network at night and the
dedicated line users under SR often use the network during the dedicated line users under SR often use the network during the
daytime. The uplink between BRAS/SR and CR must satisfy the maximum daytime. The uplink between BRAS/SR and CR must satisfy the maximum
traffic pattern between them and this causes the links traffic pattern between them and this causes the links
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+----|---+ +----|---+
| |
--------|--------|-------| --------|--------|-------|
| | | | | | | |
+--|-+ +-|- +--|-+ +-|+ +--|-+ +-|- +--|-+ +-|+
|BRAS-----SR| |BRAS-----SR| |BRAS-----SR| |BRAS-----SR|
+----+ +--+ +----+ +--+ +----+ +--+ +----+ +--+
Fig.3 Increase the link utilization via CCDR Fig.3 Increase the link utilization via CCDR
3.3. Traffic engineering for IDC/MAN asymmetric link 2.3. Traffic engineering for IDC/MAN asymmetric link
The operator's networks are often comprised by tens of different The operator's networks are often comprised by tens of different
domains, interconnected with each other, form very complex topology domains, interconnected with each other, form very complex topology
that illustrated in Fig.4. Due to the traffic pattern to/from MAN that illustrated in Fig.4. Due to the traffic pattern to/from MAN
and IDC, the links between them are often in asymmetric style. It is and IDC, the links between them are often in asymmetric style. It is
almost impossible to balance the utilization of these links via the almost impossible to balance the utilization of these links via the
distributed protocol, but this unbalance phenomenon can be overcome distributed protocol, but this unbalance phenomenon can be overcome
via the CCDR architecture. via the CCDR architecture.
+---+ +---+ +---+ +---+
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| ---------| | | ---------| |
------|BackBone|------ ------|BackBone|------
| ----|----| | | ----|----| |
| | | | | |
+-|-- | ----+ +-|-- | ----+
|IDC|----------------|MAN| |IDC|----------------|MAN|
+---| |---+ +---| |---+
Fig.4 TE within Complex Multi-Domain topology Fig.4 TE within Complex Multi-Domain topology
3.4. Network temporal congestion elimination. 2.4. Network temporal congestion elimination.
In more general situation, there are often temporal congestion In more general situation, there are often temporal congestion
periods within part of the service provider's network. Such periods within part of the service provider's network. Such
congestion phenomena will appear repeatedly and if the service congestion phenomena will appear repeatedly and if the service
provider has some methods to mitigate it, it will certainly increase provider has some methods to mitigate it, it will certainly increase
the satisfaction degree of their customer. CCDR is also suitable for the satisfaction degree of their customer. CCDR is also suitable for
such scenario that the traditional distributed protocol will process such scenario that the traditional distributed protocol will process
most of the traffic forwarding and the controller will schedule some most of the traffic forwarding and the controller will schedule some
traffic out of the congestion links to lower the utilization of them. traffic out of the congestion links to lower the utilization of them.
Section 4 describes the simulation process and results about such Section 4 describes the simulation process and results about such
scenario. scenario.
4. CCDR Simulation. 3. CCDR Simulation.
The following sections describe the topology, traffic matrix, end- The following sections describe the topology, traffic matrix, end-
to-end path optimization and congestion elimination in CCDR to-end path optimization and congestion elimination in CCDR
simulation. simulation.
4.1. Topology Simulation. 3.1. Topology Simulation.
The network topology mainly contains nodes and links information. The network topology mainly contains nodes and links information.
Nodes used in simulation have two types: core nodes and edge nodes. Nodes used in simulation have two types: core nodes and edge nodes.
The core nodes are fully linked to each other. The edge nodes are The core nodes are fully linked to each other. The edge nodes are
connected only with some of the core nodes. Fig.5 is a topology connected only with some of the core nodes. Fig.5 is a topology
example of 4 core nodes and 5 edge nodes. In CCDR simulation, 100 example of 4 core nodes and 5 edge nodes. In CCDR simulation, 100
core nodes and 400 edge nodes are generated. core nodes and 400 edge nodes are generated.
+----+ +----+
/|Edge|\ /|Edge|\
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| +------\ +----+ | +------\ +----+
| ---|Edge| | ---|Edge|
+-----------------/ +----+ +-----------------/ +----+
Fig.5 Topology of simulation Fig.5 Topology of simulation
The number of links connecting one edge node to the set of core The number of links connecting one edge node to the set of core
nodes is randomly between 2 to 30, and the total number of links is nodes is randomly between 2 to 30, and the total number of links is
more than 20000. Each link has its congestion threshold. more than 20000. Each link has its congestion threshold.
4.2. Traffic Matrix Simulation. 3.2. Traffic Matrix Simulation.
The traffic matrix is generated based on the link capacity of The traffic matrix is generated based on the link capacity of
topology. It can result in many kinds of situations, such as topology. It can result in many kinds of situations, such as
congestion, mild congestion and non-congestion. congestion, mild congestion and non-congestion.
In CCDR simulation, the traffic matrix is 500*500. About 20% links In CCDR simulation, the traffic matrix is 500*500. About 20% links
are overloaded when the Open Shortest Path First (OSPF) protocol is are overloaded when the Open Shortest Path First (OSPF) protocol is
used in the network. used in the network.
4.3. CCDR End-to-End Path Optimization 3.3. CCDR End-to-End Path Optimization
The CCDR end-to-end path optimization is to find the best end-to-end The CCDR end-to-end path optimization is to find the best end-to-end
path which is the lowest in metric value and each link of the path path which is the lowest in metric value and each link of the path
is far below link's threshold. Based on the current state of the is far below link's threshold. Based on the current state of the
network, PCE within CCDR architecture combines the shortest path network, PCE within CCDR architecture combines the shortest path
algorithm with penalty theory of classical optimization and graph algorithm with penalty theory of classical optimization and graph
theory. theory.
Given background traffic matrix which is unscheduled, when a set of Given background traffic matrix which is unscheduled, when a set of
new flows comes into the network, the end-to-end path optimization new flows comes into the network, the end-to-end path optimization
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| | | |
20| | 20| |
| *| | *|
| * *| | * *|
| * * * * * ** * *| | * * * * * ** * *|
0+-----------------------------------------------------------+ 0+-----------------------------------------------------------+
0 100 200 300 400 500 600 700 800 900 1000 0 100 200 300 400 500 600 700 800 900 1000
Flow Number Flow Number
Fig.6 Simulation result with congestion elimination Fig.6 Simulation result with congestion elimination
4.4. Network temporal congestion elimination 3.4. Network temporal congestion elimination
Different degree of network congestion is simulated. The congestion Different degree of network congestion is simulated. The congestion
degree (CD) is defined as the link utilization beyond its threshold. degree (CD) is defined as the link utilization beyond its threshold.
The CCDR congestion elimination performance is shown in Fig.7. The The CCDR congestion elimination performance is shown in Fig.7. The
first graph is the congestion degree before the process of first graph is the congestion degree before the process of
congestion elimination. The average CD of all congested links is congestion elimination. The average CD of all congested links is
more than 10%. The second graph shown in Fig.7 is the congestion more than 10%. The second graph shown in Fig.7 is the congestion
degree after congestion elimination process. It shows only 12 links degree after congestion elimination process. It shows only 12 links
among totally 20000 links exceed the threshold, and all the among totally 20000 links exceed the threshold, and all the
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| | | |
| | | |
5 | | 5 | |
| | | |
| * ** * * * ** * ** * | | * ** * * * ** * ** * |
0 +-----------------------------------------------------------+ 0 +-----------------------------------------------------------+
0 0.5 1 1.5 2 0 0.5 1 1.5 2
Link Number(*10000) Link Number(*10000)
Fig.7 Simulation result with congestion elimination Fig.7 Simulation result with congestion elimination
5. CCDR Deployment Consideration. 4. CCDR Deployment Consideration.
With the above CCDR scenarios and simulation results, we can know it With the above CCDR scenarios and simulation results, we can know it
is necessary and feasible to find one general solution to cope with is necessary and feasible to find one general solution to cope with
various complex situations for the most complex optimal path various complex situations for the most complex optimal path
computation in centrally manner based on the underlay network computation in centrally manner based on the underlay network
topology and the real time traffic. topology and the real time traffic.
[draft-wang-teas-native-ip] gives the principle solution for above [draft-wang-teas-native-ip] gives the principle solution for above
scenarios, such thoughts can be extended to cover requirements that scenarios, such thoughts can be extended to cover requirements that
are more concretes in future. are more concretes in future.
6. Security Considerations 5. Security Considerations
TBD TBD
7. IANA Considerations 6. IANA Considerations
TBD TBD
8. Conclusions 7. Conclusions
TBD TBD
9. References 8. References
9.1. Normative References
[RFC4655] Farrel, A., Vasseur, J.-P., and J. Ash, "A Path
Computation Element (PCE)-Based Architecture", RFC 8.1. Normative References
4655, August 2006,<http://www.rfc-editor.org/info/rfc4655>.
[RFC5440]Vasseur, JP., Ed., and JL. Le Roux, Ed., "Path [RFC5440]Vasseur, JP., Ed., and JL. Le Roux, Ed., "Path
Computation Element (PCE) Communication Protocol Computation Element (PCE) Communication Protocol
(PCEP)", RFC 5440, March 2009, (PCEP)", RFC 5440, March 2009,
<http://www.rfc-editor.org/info/rfc5440>. <http://www.rfc-editor.org/info/rfc5440>.
[RFC8283] A.Farrel, Q.Zhao et al.," An Architecture for Use of PCE [RFC8283] A.Farrel, Q.Zhao et al.," An Architecture for Use of PCE
and the PCE Communication Protocol (PCEP) in a Network with Central and the PCE Communication Protocol (PCEP) in a Network with Central
Control", [RFC8283], December 2017 Control", [RFC8283], December 2017
9.2. Informative References 8.2. Informative References
[I-D. draft-ietf-teas-pcecc-use-cases] [I-D. draft-ietf-teas-pcecc-use-cases]
Quintin Zhao, Robin Li, Boris Khasanov et al. "The Use Cases for Quintin Zhao, Robin Li, Boris Khasanov et al. "The Use Cases for
Using PCE as the Central Controller(PCECC) of LSPs Using PCE as the Central Controller(PCECC) of LSPs
https://tools.ietf.org/html/draft-ietf-teas-pcecc-use-cases-00 https://tools.ietf.org/html/draft-ietf-teas-pcecc-use-cases-00
March,2017 March,2017
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https://tools.ietf.org/html/draft-wang-teas-pce-native-ip-03 March https://tools.ietf.org/html/draft-wang-teas-pce-native-ip-03 March
13, 2017 13, 2017
[I-D. draft-wang-pcep-extension for native IP] [I-D. draft-wang-pcep-extension for native IP]
Aijun Wang, Boris Khasanov et al. "PCEP Extension for Native IP Aijun Wang, Boris Khasanov et al. "PCEP Extension for Native IP
Network" https://datatracker.ietf.org/doc/draft-wang-pce-extension- Network" https://datatracker.ietf.org/doc/draft-wang-pce-extension-
native-ip/ native-ip/
10. Contributors: 9. Contributors:
Tingting Yuan Tingting Yuan
Beijing University of Posts and Telecommunications Beijing University of Posts and Telecommunications
yuantingting@bupt.edu.cn yuantingting@bupt.edu.cn
Qiong Sun Qiong Sun
sunqiong.bri@chinatelecom.cn sunqiong.bri@chinatelecom.cn
Xiaoyan Wei Xiaoyan Wei
China Telecom Shanghai Company China Telecom Shanghai Company
weixiaoyan@189.cn weixiaoyan@189.cn
Dingyuan Hu Dingyuan Hu
Beijing University of Posts and Telecommunications Beijing University of Posts and Telecommunications
hdy@bupt.edu.cn hdy@bupt.edu.cn
11. Acknowledgments 10. Acknowledgments
TBD TBD
Authors' Addresses Authors' Addresses
Aijun Wang Aijun Wang
China Telecom China Telecom
Beiqijia Town, Changping District Beiqijia Town, Changping District
Beijing,China Beijing,China
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