Internet DRAFT - draft-zzl-tvr-use-case-tidal-network
draft-zzl-tvr-use-case-tidal-network
TVR L. Zhang, Ed.
Internet-Draft T. Zhou
Intended status: Standards Track J. Dong
Expires: 14 September 2023 Huawei
13 March 2023
Use Case of Tidal Network
draft-zzl-tvr-use-case-tidal-network-00
Abstract
The tidal effect of traffic is very typical on our network, this
document introduces the time variant routing scenario in the tidal
network, and then describes the assumptions and routing impacts based
on the use case. Finally, an exempar of a network to the use case is
provided.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 2
2. Assumptions . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Routing Impacts . . . . . . . . . . . . . . . . . . . . . . . 3
4. Exemplar . . . . . . . . . . . . . . . . . . . . . . . . . . 4
5. Security Considerations . . . . . . . . . . . . . . . . . . . 5
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
7. Normative References . . . . . . . . . . . . . . . . . . . . 5
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6
1. Introduction
The tidal effect of traffic is very typical on our network, and the
traffic volume varies greatly at different times. For example, in
the Chinese New Year, there are 200 million people move from their
work town to home town, and these people generate huge traffic on our
network. For the campus network, there are thousands of people go to
the Teaching buildings, libraries and labs in the daytime and go to
dormitory in the night. Therefore, the traffic of different places
in the campus fluctuate obviously and regularly.
In the previous scenarios, If the network maintains all the devices
up to guarantee the maximum throughput all the time, a lot of power
will be wasted. Therefore, it is an effective energy-saving method
to shut down some devices when the traffic is low. Thus, a scenario
in which the network connection status can be predicted is formed in
the tidal network.
This document introduces the time variant routing scenario in the
tidal network, and then describes the assumptions and routing impacts
based on the use case. Finally, an exemplar of a network to the use
case is provided.
1.1. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in
BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
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2. Assumptions
In order to reduuce energy consumption based on the regularity of
tidal traffic, the controller or other control device needs to know
the rule of traffic changing. It is assumed that there is a
algorithm that can calculates which nodes and links should be
disabled or enabled under different traffic scales. Finally, it is
assumed that there is a method to config the switching rules for each
node.
1. Known the regularity of tidal traffic, It is assumed that the
controller or other control device knows the regularity of tidal
traffic, and the change of traffic in the future can be
predicated. The regularity information may come from the manual
input or the results of computer's calculation.
2. An algorithm to calculate which nodes or links can be disabled or
enabled under different traffic scales. It is assumed that the
controller or other control device supports a algorithm to
calculate the minimal topology that satisfies the requirements of
traffic at different time. Based on that, it is known which
nodes or link should be disabled or enabled under different
traffic scales.
3. Routing Impacts
The change of link status will change the topology of the network.
Furthermore, the data routing may be affected which may result in
packet disorder or packet loss. In order to solve these problems,
the existing routing protocols may need to provide the following
capabilities.
1. Data model with time-variant information. There is a need for
the nodes or controllers to deliver the predicated time-variant
information by specific data model or structure. For the tidal
network, the change of network topology usually has a regular
period, and the overlay of mutiple groups of time-variant
information (For example, the regularity of traffic in campus
network is quite differern on weekdays and weekend) also should
be considered.
2. Collection and advertisement for the time-variant information of
each node and link. For the distributed routing protocols, each
node needs to calculate the routing table, so it is required that
each node advertise its own time-variant information(This step is
not necessary when every node knows all of the time-variant
information about the topology). For the centralized routing
protocols, the controller is responsible for the calculation of
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routing path, so the controller may need to collect the time-
variant information of all the nodes(It is also not necessary
when the controller already knows all of the time-variant
information about the topology).
3. Routing algorithm based on time-variant information. When the
routing calculator knows the time-variant information of each
node, there is a need for a new algorithm to calculate the
routing paths, it may be quite different from the existing
algorithm.
4. Exemplar
One example of a network with tidal traffic is the campus network,
the traffic in the dormitory will raise in the evening and drop in
the morning. In contrast, the traffic in the library will raise in
the morning and almost drop to zero at night. the traffic of campus
changes with a significant period.
Consider a four nodes network, and the traffic of the network at
different time is shown in Figure 1.
T |
R | ------ ------
A | / \ / \
F | / \ / \
F | / \ / \
I |/ ------------/
C +---++----++-----------------++------++---
t1 t2 t1+T t2+T
Time
Figure 1: Traffic of the network at different time
The topology of network is shown in Figure 2
N1---------L1---------N2
| \ / |
| \ / |
| \ / |
| L6 L5 |
L2 \/ L3
| / \ |
| / \ |
| / \ |
| / \ |
N3--------L4----------N4
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Figure 2: Topology of a four node network
In order to reduce the power consumption, some of the links may be
shut down during the period form t1+nT to t2+nT(n=0,1,2,...). For
example, link L5 and L6 can be shut down when the traffic is low, so
the possible time-variant topology is as shown in Figure 3
N1---------L1---------N2 N1---------L1---------N2
| \ / | | |
| \ / | | |
| \ / | | |
| L6 L5 | | |
L2 \/ L3 L2 L3
| / \ | | |
| / \ | | |
| / \ | | |
| / \ | | |
N3---------L4--------N4 N3---------L4--------N4
Topology1 (form t1+T to t2+T) Topology 2(form t2+T to t1+T)
Figure 3: Time-variant topology
In this example, The controller is required to deliver the time-
variant information of link L5 and L6 to the related nodes, and then
the controller or each node(Every node has already known the time-
variant information of topology) needs to calculate the routing path
with the time-variant information of L5 and L6. It should be noted
that if there are some packets being transmitted over link L5 or L6
at time t1, the shutdown of L5 and L6 may cause packet loss until the
source node computes a new routing path. The new routing mechanism
may need solve these problems of tidal network.
5. Security Considerations
TBD
6. IANA Considerations
TBD
7. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
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[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
Authors' Addresses
Li Zhang (editor)
Huawei
Beiqing Road
Beijing
China
Email: zhangli344@huawei.com
Tianran Zhou
Huawei
Email: zhoutianran@huawei.com
Jie Dong
Huawei
Email: jie.dong@huawei.com
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