Computer Science, asked by prinkle4292, 1 year ago

An sdn controller can be placed based on which topology

Answers

Answered by abdulkurban
0
Therefore, it is network management becomes a real challenge, especially large networks. The growth of network and
information technology serve the needs for better service in term of quality, availability, and dependability, elasticity,
and security 1
. These requirements drastically increased the complexity of networks and current network should be
able to support heterogeneous applications, technologies, and multi-vendor equipment, causing the network
management to become a challenge. Software Defined Networks (SDN) is the latest networking model with many
potentials to further enhance the network abilities in term of simplification, efficiency, management and control.
Furthermore, better enhance the innovation rate for the future of technology 2
.
SDN becoming an interesting area for both researching and industrialization. They began to put more efforts and
investments to better develop it. Through a unified plane, SDN can control the network with different vendor
equipment and view an abstract view of the network resources. It provides a simplified and programmable network
which can afford better network management and maintenance. Unlike traditional networks which forwarding devices
search for the network path, making routing decisions, and running protocols. Also, they forward packets to their next
destination. However, in SDN the data plane is separated from control plane. This means that the network has a logical
centralized control unit and all the intelligence is removed from network equipment. Logical centralization doesn’t
mean that the control unit is physically centralized, which leads to single point failure 3,4.
Managing networks in SDN network requires the SDN controller to have fresh information about the condition of
the network, especially topology. Therefore, its essential to have reliable mechanism to discover the network topology.
The SDN controller should have information about every device in the networks and the connection channels which
links them. To keep the service running a almost real-time vision about the topology of the network in an SDN network
is mandatory, especially for the large networks. The current protocol which is operated by current controllers is
OpenFlow Discovery Protocol which facilitate the topology discovery. However, this protocol lack efficiency issues 5
. It also has reliability issues when applied in large network with heavy traffic. To solve these problems, 2 introduced
a novel solution to reduce the load on the network during discovery periods called OpenFlow Discovery Protocol v2
(OFDP v2). They provided two solutions to improve the efficiency of topology discovery in SDN Network called
(OFDPv2A) and (OFDPv2B). However, they didn’t investigate the protocol in term of retransmission of the discovery
packets. In this paper, we have redone 2 work in topology discovery using OpenFlow Discovery Protocol v.2B (OFDP
v.2B). We chose to use this particular protocol to put the load of the topology discovery solely on the network
controller. We intended to find out about the flow of traffic when the SDN network undergo topology discovery
procedure. The empirical analysis shows that our simulation reveals different results patterns when we take
retransmitted OpenFlow packets into consideration.
2. OpenFlow
The Internet experienced the virtualization in general way, more specifically, SDN which makes
networks customizable and programmable. SDN uses OpenFlow protocol to decouple data plane from
control plane in the network and put all the intelligence in a single logical component called controller.
The controller manages the network and decides where a traffic flow should go 6
. OpenFlow opens a
portal between network applications and network forwarder in SDN environment which grants the
controller necessary access to manage and configure the network switches. Other protocols like BGP,
SNMP, PCEP, etc are utilized at forwarder’s
illustrates the structure of SDN networks and
its components.
In order to maintain the service, SDN controller should keep updating the information about the
network and its topology 2,3. One of the critical tasks which the controller is responsible for is almost
real-time sight of the network topology which is known as Topology Discovery. Compared to legacy
protocols which depends on Link State (i.e. OSPF), Topology Discovery in SDN is more critical. All
network controllers are using (OFDP) protocol to discovery network topology in an SDN network by
using Link Layer Discovery Protocol (LLDP) frames in form of messages
Answered by emspsaheenpdh14w
0

All topology supports

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