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level: Chapter 7

Questions and Answers List

level questions: Chapter 7

QuestionAnswer
what is Box-by-Box operations that done in network devices ?- Traditionally, Network Management is about - Installation and initial config - modifying and updating the existing config - upgrading software - all of those were achieved by :Console, Telnet, SSH, applying scripts or by copying config - and, Monitoring - which was achieved through : SNMP, and Netflow
how Automation help us ?- new devices automatically finds an initial configuration - automated QoS profiles/config - automated AAA profiles/config - utilizes scripts/tools - standardize some procedures - schedule operations - sometimes, automated troubleshooting (WoW) So smaller staff is needed, time saving, and config consistency.
what is SDN ?Software-Defined Networking (SDN) - Automation is achieved by SDN - where you have a “software” that runs your network - so, through a “software” you be able to run and administrate An entire network, with its different types of devices - that will definitely need either a “Controller”!!! Or, a built-in scripting (Cisco TCL, or Python) .
what is SDN Controller ?- controls and implement the automation and administration - can either be - A “software” installed in a server - An appliance with a controller inside (Cisco APIC, DNA Center) - Or, a remote controller through the cloud - and, it uses some tools/apps like (puppet, chef, and ansible)
SDN has 2 Type of Implementation ?- Imperative Approach - Declarative Approach
what is Imperative Approach ?- the control plane logic resides completely in the controller - the controller has a complete control over programing the The forwarding decisions of the networking devices - devices then will ask the controllers before any forwarding Or routing action
what is Declarative Approach ?the control plane resides within the network device (just like before) - the controller will declare the requirements of the all the Forwarding/routing decisions to the networking devices - the network devices will then decide how to translate the Controller instructions into actions
what is SDN Architecture ?- Underlay Network - the protocols & features to get reachability - all the links must be L3 and P2P - open standard protocols (OSPF and IS-IS) - Overlay Network - Virtual Network created on top of the Underlay - now the underlay is like a “physical connectivity” - some protocols use (VRF, MPLS-VPN, VXLAN)
what does it mean SDN Fabric ?- the physical devices used to build the underlay - those devices can be controlled by a “Controller”
what are the 3 planes in the network devices ?1-Control Plane 2- Data Plane 3-Management Plane
what is Control plane ?- learn information from the protocols - downloads them to the Data planes (as Tables) - protocols resides here (routing protocols, MAC learning, DHCP, AAA, etc...)
what is Data plane ?- also known as Forwarding Plane - any logical/physical component that controls the frame/packet Forwarding (action) - like Tables (MAC Table, Routing Table)
what is Management Plane ?- responsible for AAA (remotely) - also, the console port resides in here
so how SDN will effect the planes ?depends on the implementation approach if it was an Imperative approach - also called a “Stateful SDN” OR - if it was a Declarative approach - also called a “Stateless SDN”
what is DNA center ?Cisco DNA Center - the Digital Network Architecture - it is an Appliance (comes in various models) - A Central Management, Automation, and Analysis Point - gives Intent-Based Networking - and that is, controlling a network by a software - allows to design and create topology maps - design WLAN SSIDs ,managed through a GUI .
what are APIC and NDP ?- has a built-in APIC - the Application Policy Infrastructure Controller - it’s controller - also has a built-in NDP - Network Data Platform - analyzes problems, show them, and suggest solutions
what is API ?transforms data between different controllers of different devices - so, it’s a code - written by a language - that language encodes data into an API - it uses the Server/Client relation - in the Northbound (Controller = Server, Application = Client) - in the Southbound (Network Device = Server, Controller = Client)
what is a northbound api ?- the transformers that are transforming everything from The Application to the controllers, and vice-versa - those will be called “Northbound API”
what is a southbound api ?- also transforms everything from the controller to the network Devices, and vice-versa - the “Southbound API”
what are API types ?- Internal API - between applications - like transferring data from HTML to PDF - Web-Service API - exchanging data between remote devices - Uses IP address - like REST-Based API ,*some Southbound APIs (Openflow, Cisco OpFlex, CLI, SNMP, NETCONF)
what is REST-Based APIs ?Representational State Transfer the most common type of web-service API, mostly found in the Northbound. utilizes HTTP verbs (GET, PUT, POST, DELETE) - while a REST API is in developing, a developer would use A CRUD to develop the API’s HTTP verbs ==>CRUD = Create, Read, Update, and Delete.
most common languages used to encode data in a REST-Based API ?(XML, and JSON) encoding means standardizing a data structure between the app, Controller, and nodes.
what are the applications that you use to automate ?(Puppet, Chef, and Ansible). the applications that you use to automate - all of them requires CLI/Scripting - includes a GUI - schedule a task - manually instantiate events - so, a CLI script will give a GUI result
what are Puppet & Chef ?uses the Master/Agent relation - 2 codes - one in the server, other in the node - uses the Pull Model - an agent will periodically ask a master for event and actions, And Pulls the script from it - uses the RUBY language
what is Ansible?- Agentless - uses the Push Model - Master pushes a config to the agent - uses the YAML language
what is (JSON) ?- a programming language used to create APIs - used by REST-Based APIs - human-readable - lightweight - the “Object” is about - a container that encloses “one-or-more” {name:value} pairs - also called a “key-value pairs”
what does JSON Values means ?always surrounded by a curly bracket { } - name:value pairs - a string must be enclosed with double quotes “ ” like ={“name”:”III”,“job”:”channel”,“location”:”YouTube”}.