Automation, Network Virtualization, Troubleshooting IP Connectivtity

* C progarmming language is often used to program the firmware that accesses the hardware.

Control plane

- typically the brains of a device. - it is used to make forwarding decisions the control plane contains layer 2 and layer 3 route mechanisms such as routing protocol neighbor tables and topology tables, ipb4 and ipv6 routing tables, stp and the arp table.

Features of RESTful API: o Client-server - the client handles the front end and the server handles the back end. Either can be replaced independently of the other o Stateless - No client data is stored on the server between requests. The session state is stored on the client Cacheable - clients can cache responses to improve performance

REST and RESTful API Web browsers use HTTP or HTTPS to request (GET) o If successful (HTTP status code 200), web serves respond to GET requests with an HTML coded web page

Simple Network Management Protocol (SNMP)

Not typically used for configuration due to security concerns and difficulty in implementation

Data format specific characteristics: o Syntax - includes types of brackets (), [], {}, the use of white space or indention, quotes, commas, etc. o Object representation - characters, strings, lists, arrays o Key/Value pair representation · Key - usually on the left side; identifies or describes the data · Value - on the right; is the data itself and can be character, string, number, list or another type of data

Data Format Rules

Data formats have rules and structure similar to what we have in programming and written languages.

Dedicated Servers: Server sprawl server Virtualization Hypervisor Abstraction layer

JavaScript Object Notation-Remote Procedure Call (JSON-RPC)

Similar to XML-RPC

Cacheable

clients can cache responses to improve performance

can use show interface if you're interested in the output: Interface status Input queue drops Output queue drops (packets were dropped due to congestion on the interface) Input errors Output errors

can use show interface if you're interested in the output: Interface status Input queue drops Output queue drops Input errors Output errors

Smart devices

devices that can take a course of action based on an outside piece of information. This indicates that the devices has the ability to alter its behavior depending on its environment

show ipv6 access-list

display all the contents of all the ipv6 acls configured in a router

show ip access-list

display the contents of all the ipv4 acls and

nslookup

display the name to ip address mapping information

show ip interface and show ipv6 interfaces

displays ipv4 and ipv6 interface information

Object representation

characters, strings, lists, arrays

Duplex Mismatch

failure connection to switch to switch

Controller-based SDN

uses a centralized controller that has knowledge of all devices in network.

SDN controller

uses northbound APIs to communicate with the upstream applications, helping network administrators shape and deploy services.

SDN controller

uses southbound APIs to define the behavior of the data planes on downstream switches and routers.

Key/Value pair representation: Key

usually on the left side; identifies or describes the data

Values

valid JSON data type (string, number, array. Boolean, null, object)

Cisco ACI

very few organizations actually have the desire or skill to program the network using sdn tools.

White space

not significant

Tools to make Configuration Management Easier:

o Ansible o Chef o Puppet o SaltStack

Step 7: Verify ACLs

there may be ACLs that prohibit the passing or from passing through the interface in the inbound or outbound direction

Cisco Nexus 9000 Series switches

these switches provide an applicable -aware switching fabric and work with an APIC to manage the virtual and physical network infrastructure.

OpenStack

this approach is a virtualization and orchestration platform designed to build scalable cloud environments and provide an IAAS

OpenFlow

this protocol is a basic element in building SDN solutions.

Flow Table

this table matches incoming packets to a particular flow and specifies the functions that are to be performed on the packets. -there may be multiple flow tables that operate in a pipeline fashion.

Meter Table

this table triggers a variety of performance-related actions on a flow including the ability to rate-limit the traffic.

* The use of virtualization normally includes redundancy to protect from a single point of failure.

* difference between the operation of localized control on a layer 3 switch and a centralized controller is the end follows.

* hypervisors are free however some hypervisors offer more advanced features for a fee.

*how is the network virtualized? the answer is found on how a networking device operates using a data plane and control pane.

Software-Defined Network (SDN)

- a network architecture that virtualizes the network, offering new approach to network administration and management that seeks to simplify and streamline the administration process.

Cisco Application Centric Infrastructure (ACI)

- a purpose-built hardware solution for integrating cloud computing and data center management.

Data plane

- also called the forwarding plane this plane is typically in the switch fabric connecting the various network ports on a device. - the data plane of each device is used to forward traffic flows

The Complexity of Network Virtualization

- another problem is that traffic flows differ substantially from the traditional client server model so typically a data center has a considerable amount of traffic being exchanged between virtual servers such as the UCL servers. -dynamic ever-changing traffic requires a flexible approach on network resource management okay so existing network infrastructure can respond to changing requirements related to the management of traffic flows by using the quality of service or QOS, and security level configurations for individual flaws.

Private clouds

- are intended for specific organization or entity, such as the government. - your private cloud can set up using the organization's private network so through this can be expensive to build and maintain. - private cloud can also be managed by an outside organization with strict access security

Public clouds

- cloud-based applications and services offered in public cloud that are made available to the general population so services may be free or are offered on a pay-per-use model such as paying for online storage - uses the internet to provide services

Translation

- enables the network administrator to express the expected networking behavior that will best support the business intent

Type 1 Hypervisor

- improves scalability, performance and robustness. - type 1 hypervisors require a management console to manage the hypervisor so management software is used to manage multiple servers using the same hypervisor so the management console can automatically consolidate servers and power on and off servers as required.

Control plane

- information sent to the control plane is processed by the cpu.

Cloud Computing

- involves large numbers of computers connected to a network that can be physically accessed anywhere. - can reduce operational costs by using resources efficiently.

Hypervisor

- is a program or, firmware, or hardware that adds an abstraction layer on top of the physical hardware

SDN and Central Controller: SDN

- is basically the separation of the control plane and data plane. -the control plane function is removed from each device and is performed by a centralized controller

Community clouds

- is created for exclusive use by a specific community - the differences between public clouds and community clouds are the functional needs that have been customized for the community for example healthcare organization must remain compliant with policies and laws example the HIPAA (that requires special authentication and confidentiality.

Type 1 Hypervisor (bare metal)

- is installed directly on the server or network hardware then instances of an operating systems are installed on the hypervisor. - more efficient than hosted architectures (type 2 hypervisor)

Hybrid clouds

- is made up of two or more clouds example part private and part public, where each part remains a separate object but both are connected using a single architecture - individuals on a hybrid cloud would be able to decree or to have degrees of access okay so to vary services based on the user access rights

Type-2 hypervisors

- is software that creates and runs virtual machine instances so the computer on which a hypervisor is supporting one or more VMs, is a host machine. - are also called "hosted hypervisors", this is because the hypervisor is installed on top of the existing operating systems such as mac os, windows or linux then one or more additional os instances are installed on top of the hypervisor.

Virtualization

- is the foundation of cloud computing without it cloud computing as it is most widely implemented would not be possible so virtualization separates the operating systems or os from the hardware

Abstraction layer

- is used to create a virtual machines which have access to all the hardware of the physical machines such as cpus, memory disk controllers and network interface cards.

Abstraction layer

- it helps to use layers of obstruction in computer architecture.

Assurance

- maintains a continuous validation-and-verification loop to continuously check that the expressed intent is honored by the network at any point in time

Software as a Service (SaaS)

- responsible for access to application and services such as email, communication and office 365 that are delivered over the internet so the user does not manage any aspect of the cloud service except for limited user specific application settings so the user only needs to provide their data

Infrastructure as a Service (Iaas)

- responsible for giving IT managers access to network equipment virtualized network services and supporting network infructure. So using this service allows IT managers to deploy and run software code which can include operating systems and application.

Platform as a Service (PaaS)

- responsible for providing user access to the development tools and services used to deliver the applications the users are typically programmers and may have control over the configuration settings of the cloud provider's application hosting environment.

Underlay Control Plane

- responsible for simple forwarding tasks. o Refers to the traditional networks that we have

Data plane

- routers and switches use information from the control plane to forward incoming traffic out of the appropriate egress interfaces -information in the data plane is typically processed by special data plane processor without the cpu getting involved.

server Virtualization

- takes advantage of idle resources and consolidates the number of required servers so this also allows for multiple operating systems to exist on a single hardware platform.

Activation

- the captured intent needs to be interpreted into policies that can be applied across the network. · Installs these policies into the physical and virtual network infrastructure using network-wide automation

Cisco DNA Center

- the foundational controller and analytics platform at the heart of Cisco DNA o Supports the expression of intent for multiple use cases, including basic automaton capabilities, fabric provisioning, and policy-based segmentation in the enterprise network

Server sprawl

- this servers wasted energy and took up more space than was warranted by the amount of service provided.

Data center

- typically an off premise or a data storage and processing facility run by an in-house id department or list offsite. - are the physical facilities that provide the computer network and storage needs of cloud computing services

Cloud computing

- typically this is an off-premise service that offers an on-demand access to a shared pool of configurable computing resources so these resources can be rapidly provisioned and released with minimal management effort. - use data centers to host their cloud services and cloud-based resources.

Virtualization

- various providers offer virtual cloud services that can dynamically provision servers as required for example amazon web services or AWS provides a simple way for customers to dynamically provision the computer resources they need. -these virtualized instances of servers are created on demand.

Type 2 hypervisor

- very popular with consumers for organizations, experimenting with virtualization. - common type to hypervisor includes virtual pc or the vmware workstation.

Management plane

-Network administrators and systems administrators use the application such as secure shell (SSH), Trivial File Transfer Protocol (TFTP), Secure Hypertext Transfer Protocol (HTTPS) to access the management plane configure a device.

Underlay Network

-Network is the physical topology that includes all hardware required to meet business objectives. -Reveals additional devices and specifies how these devices are connected

URI

-Web resources and web services such as RESTful APIs are identified using -a string of characters that identifies a specific network resource.

Cisco ACI

-is a hardware solution for integrating cloud computing and data center management. -at a high level, the policy element of the network is removed from the data plane.

The Complexity of Network Virtualization

-server virtualization hides server resources such as the number and identity of physical servers processors and OSS from server users. So this practice can create problems if the data center is using traditional network architectures. - VMs are movable and the network administrator must be able to add drop or change network resources and profiles so this process would be manual and time consuming with additional network switches.

SDN

-the centralized controller communicates control plane functions to each device. - each device can now focus on forwarding data while the centralized controller manages data flow, increases security and provides other services.

The Complexity of Network Virtualization

-the network infrastructure can also benefit from virtualization. Network functions can be virtualized each network device can be segmented into multiple virtual devices that operate as independent devices examples includes sub-interfaces virtual interfaces vlans and routing tables. Virtualized routing is called "virtual routing" and "forwarding (VRF)."

Data formats

A well designed for is dictated by what makes the information the easiest for the intended audience to understand. This principle also applies to shared data between computers

API acts as an messenger between the requesting application and the application on the server

APIC-EM Features: -Discovering and accessing device and host inventories -Viewing the topology -Tracing a path between end points -Setting policies

Policy-based SDN

APIC-EM is an example

Abstraction layers: CPU, Memory, NIC Disk Firmware (ROM) Os Services like web mail and file services

Additional benefits of Virtualization -easier prototyping - faster server provisioning - increased server uptime - improved disaster recovery - legacy support

Advantages of Virtualization: -reduced cost -less equipment is required (virtualization enables server consolidation which requires fewer physical servers, fewer networking devices and less supporting infrastructure so it means lower maintenance cost) -less energy is consumed (consolidating servers lowers the monthly power and cooling costs so reduced consumption helps enterprises to achieve a smaller carbon footprint) - less space is required (server consolidation with virtualization reduces the overall footprint of the data center so fewer servers network devices and racks reduce the amount of the required floor spaces)

An important consideration when developing an API is the distinction between open, internal, and partner APIs: o Open APIs or Public APIs - publicly available and can be used with no restrictions o Internal or Private APIs - are used by an organization or company to access data and services for internal use only o Partner APIs - used between a company and its business partners or contractors to facilitate business between them · Must have a license or other form of permission to use the API

Anatomy of a RESTful Request A request made to a resource's URI will elicit a response. o The response will be a payload typically formatted in JSON but could be HTML, XML, and some other format

Smart devices

Are in fact "tiny computers"

Bottom-up approach: -you need to check physical connectivity at the point where network communication stops -check for duplex mismatches -check data link and network layer addressing on the local network -verify the default gateway is correct -ensure that devices are determining the correct path from the source to destination -verify the transport layers functioning properly -verify that there are no ACLs blocking the traffic -ensure that DNS settings are correct

Data Formats

The computer must put the data in a format that another computer can understand

Simple Network Management Protocol (SNMP)

Can use API to automate the deployment and management of network resources *Reduce many repetitive and mutant tasks to free up time for network administrators to work on more important things

Characteristics of Arrays in JSON: o Key followed by colon (:) and a list of values enclosed in square brackets []. o Ordered list of values o Can contain multiple value types (string, number, Boolean, object, array) Value in array separated by comma

Characteristics of Networks (that administrators benefit from automating): o Software and Version Control o Device Attributes - names, addressing , and security o Protocol configurations ACL configurations

Characteristics of XML: o It is like HTML o It is self-descriptive. It encloses data within a related set of tags : <tag>data</data> o Unlike HTML, XML uses no predefined tags or document structure

Characteristics of YAML: o Like JSON and considered a superset of JSON o Has minimalist format o Easy to read and write o Uses indention to define structure, without brackets or commas

Cloud Models : Public clouds Private clouds Hybrid clouds Community clouds

Cisco DNA solutions o SD-Access o SD-WAN o Cisco DNA Assurance o Cisco DNA Security

Cisco Digital Network Architecture (DNA)

Cisco implements IBN using Cisco DNA. The business intent Is securely deployed into the network infrastructure (the fabric).

Cloud Computing addressed many data management issues: - it enables access to organizational data anywhere at any time. - Streamlines the organization's IT operations by subscribing only to needed services. - eliminates or reduces the need for onsite IT equipment, maintenance, and management. -reduces cost for equipment, energy, physical plant requirements, and personnel training needs. - enables rapid responses to increasing data volume requirements.

Cloud computing with its pay as you go model allows organization to trip computing and storage expenses more as utility rather than investing in the infrastructure so capital expenditures are transformed into operating expenditure.

Cloud services (Cloud provider) : -Software as a Service (SaaS) -Platform as a Service (PaaS) -Infrastructure as a Service (Iaas)

Cloude service providers have extended this model to also provide IT support for each of the cloud computing service (ITaaS). For businesses, ITaaS can extend the capability of the network without requiring investment in new infrastructure, training new personnel, or licensing new software.

Components of the sdn: OpenFlow OpenStack Other components

DNA Center's Main Areas: o Design - model your network o Policy - use policies to automate and simplify network management, reducing cost and risk while speeding rollout of new and enhanced services o Provision - provide new services to users with ease, speed, and security across enterprise network o Assurance o Platform

RPC

Done without having to know the details of the network

Network Infrastructure as Fabric

From the perspective if IBN, the physical and virtual network infrastructure is a fabric. o an overlay that represents the logical topology used to virtually connect to devices

Goal of these tools is to reduce the complexity and time involved in configuring and maintaining a large-scale network infrastructure with hundreds, even thousands of devices

IPv6 default gateway can be configured manually, using SLAAC or by using DHCPv6

OpenStack

IS OFTEN USED WITH Cisco ACI -Orchestration in networking is the process of automating the provision of network components such as servers, storage, switches, routers, and applications.

eXtensible Markup Language-Remote Procedure Call (XML-RPC)

Is a protocol developed prior to SOAP

JSON

Is a very popular format used by web services and APIs to provide public data.

JSON

It is easy to parse and can be use with most modern programming languages, including Python

Policy-based SDN

It uses a built-in applications that automate advanced configuration tasks via a guided workflow and user-friendly GUI.

JSON Syntax Rules Characteristics of JSON: o Uses hierarchical structure and contains nested values o Use braces {} to hold objects and brackets [] to hold arrays o Written as key value pairs

Many RESTful APIs, including public APIs, require a key. The key Is used to identify the source of the request.

Many devices now incorporate smart technology to help to govern their behavior. This can be as simple as a smart appliance lowering its power consumption during periods of peak demand or as complex as a self-driving car

Network Virtualization Technologies Two major network architectures have been developed to support network virtualization: -Software-Defined Network (SDN) -Cisco Application Centric Infrastructure (ACI)

Traditional Network Configuration

Network devices have been traditionally configured using CLI. Necessary commands must be entered on all of the appropriate devices. o This becomes a major issue on larger networks or with more complex configurations

Stateless

No client data is stored on the server between requests. The session state is stored on the client

Policy-based SDN

No programming skills are required. Cisco APIC-EM is an example of this type of SDN

Parts of the API Request: o API Server - URI for the server that answers REST requests o Resources - specifies the API that is being requested o Query - specifies the data format information the client is requesting from the API service o Format - JSON, YAML, or XML o Key - is for authorization if required o Parameters - used to send information pertaining to the request

Parts of the URI (https://www.example.com/author/book.html#page155) · Protocol/Scheme - HTTP, FTP, SFTP, mailto, and NNTP · Hostname - www.example.com · Path and file name - /author.book.html · Fragment - #page155

RESTful Implementation Restful web service - is implemented using HTTP. It is a collection of resources with four defined aspects: o Base Uniform Resource Identifier (URI) for the web service o Data format supported by the web service (JSON, YAML, XML) o Set of operations supported by the web service using HTTP methods o API is hypertext driven

Reasons Why API provider may require a key: o To authenticate the source to make sure they are authorized to use the API o To limit the number of people using the API o To limit the number of requests per user o To better capture and track the data being requested by users o To gather information on the people using the API

Traditional and SDN Architectures

Routing decisions and packet forwarding are the responsibility of the device in the operating system.

SDN Controller and Operations -the controller populates flow tables -switches manage the flow tables

SDN Controller and Operations OpenFlow protocols uses Transport Layer Security (TLS) to securely send control plane communications over the network so each open flow switch connects to other open flow switches they can also connect to the end user devices.

SDN Controller and Operations each flow traveling through the network must first get permission from the sdn controller, which verifies that the communication is permissible according to the network policy.

SDN Controller and Operations if the controller allows a flow it computes a route for the flow to take and add an entry for that flow in each of the switches along the path so all complex functions are performed by the controller

SDN Controller and Operations within each switch, a series of tables implemented in hardware and firmware are used to manage the flow of packets through the switch.

SDN Types: Device-based SDN Controller-based SDN Policy-based SDN

API

Set of rules describing how one application can interact with another, and instructions to allow the interaction to occur

Software-Defined Networking A network device contains the following planes: -Control plane -Data plane

Specializations: · Uniform Resource Name (URN) - identifies only the namespace of the resource (web page, document, image, etc) without reference to the protocol · Uniform Resource Locator (URL) - defines the network location of a specific resource. HTTP or HTTPs URLs are typically used with web browsers § Protocols such as FTP, SFTP, SSH, and others can use a URL § Example: sftp://sftp.example.com

Spine-Leaf Topology compared to SDN, the APIC controller does not manipulate the data path directly. And instead the APIC centralizes the policy definition and programs the leaf switches to forward traffic based on the defined policy.

Step 4: Verify Default Gateway commands: show ip route (routers) route print (or netstat -r) [for PCs]

Syntax for JSON object: o Keys - strings with quotation marks " ". Ex. "name" : "GigabitEthernet0/0/0" o Values - valid JSON data type (string, number, array. Boolean, null, object) o Key & Values - separated by colon (:) o Multiple key/value pairs - separated by commas o White space - not significant Array (in JSON) - key contains more than one value. It is an ordered list of values.

Step 3: Verify Addressing on the Local Network

The arp Windows command display as and modifies entries in the ARP cache that are used to store IPv4 addresses and their resolved Ethernet physical (MAC) addresses.

Controller-based SDN

The application can interface with the controller responsible for managing devices and manipulating traffic flows throughout the network.

The data format that is selected will depend on the format that is used by the application, tool, or script that you are using. Many systems will be able to support more than one data format, which allows the user to choose their preferred one.

o REST, Ansible, Puppet, Chef, Python, JSON, XML, and more

There are new and different methods for network administrators to automatically monitor, manage, and configure the network. These include protocols and technologies such as

These services are available on demand and delivered ecenomically to any device anywhere in th world without compromising security or function.

Three core components of ACI architecture: -Application Network Profile (ANP) -Application Policy Infrastructure Controller (APIC) -Cisco Nexus 9000 Series switches

Three table types shown in the previous figure are as follows: -Flow Table -Group Table -Mater Table

Two most common issue that affect transport layer connectivity: ACL configurations NAT configurations

API

Used in building programmable automation

XML objects are one or more key/value pairs, with the beginning tag used as the name of the key: <key>value</key>

Troubleshoot VLAN Assignment

another issue to consider when troubleshooting end-to-end connectivity

YAML format is one or more key value pairs. Key Value pairs are separated by a colon without use of quotation marks

Application Policy Infrastructure Controller (APIC)

a centralized software controller that manages and operates a scalable ACI clustered fabric. It is designed for programmability and centralized management. It translates application policies into network programming. -is often much more complex

Application Network Profile (ANP)

a collection of end-group(EPG), their connections, and the policies that defines those connections.

Switch

a flow is a sequence of packets that matches a specific entry in a flow table.

Group Table

a flow table may direct a flow to a Group Table, which may trigger a variety of actions that affect one or more flows.

SDN controller

a logical entity that enables network administrators to manage and dictate how the data plane of switches and routers should handle network traffic.

Simple Object Access Protocol (SOAP)

a messaging protocol for exchanging XML structure information most often over the HTTP or smtp

Cisco DNA

continuously gathers data from a multitude of sources (device and applications) to provide a rich context of information.

cisco application policy infrastructure controller - enterprise module (APIC-EM)

aimed at enterprise and campus deployments

APIC-EM Path Trace Tool

allow the administrator to easily visualize traffic flows and discover any conflicting duplicate or shadowed ACL entries

Virtual Network Infrastructure: Type 1 Hypervisor

also called as "bare metal"

Type 1 Hypervisor

also called as "bare metal" approach because the hypervisor is installed directly on the hardware so type 1 hypervisors are usually used on enterprise servers and data center networking devices

Duplex Mismatch

another common for interface error

YAML

another human readable data format used by applications for storing, transferring, and reading data.

REST API

an API that works on top of the HTTP protocol

Shared data formats

are also used by other devices in the network.

Device-based SDN

are programmable applications running on the device itself or on a server in the network.

The Data Formats Concept: Data Formats

are simply a way to store and exchange data in a structured format. A common language shared between two or more smart devices.

Internal or Private APIs

are used by an organization or company to access data and services for internal use only

Type 2 hypervisor

called "hosted hypervisors"

The Complexity of Network Virtualization

called "virtual routing" and "forwarding (VRF)."

Network administrator

can deploy a variety of services from the AWS management console including virtual machines web applications, virtual servers and connections to IOT devices.

arp -a

command used to verify mappings between destination ip address and the layer to internet address on individual segments

telnet utility

common tool for testing transport layer functionality

SDN controller

communicates and OpenFlow compatible switches using the openFlow protocols

RESTful

conforming to the constraints of the REST architecture

SDN controller

defines the data flows between the centralized control plane and the data planes on individual routers and switches.

Base Uniform Resource Identifier (URI)

for the web service

Step 2: Check for Duplex MIsmatches

foreign ethernet link collisions often indicates duplex negotiation has failed

DNA Center Interface launch page

gives you an overall health summary and network snapshot.

ip host

global configuration command to enter name to be used instead of the IPv4 address of the switch or router

API keys/ tokens

help control the number of API requests they receive and process

APIC-EM Path Trace Tool

his tool examines specific ACLs on the path between two end nodes displaying any potential issues you can see where any ACLs along the path either permitted or denied your traffic

Duplex mismatch

hubs fails

API

hypertext driven

JSON (JavaScript Object Notation)

is a human readable data format used by applications for storing, transferring and reading data.

if full duplex negotiation fails for some reason it might be necessary to set the speed and duplex manually on both ends so typically this would mean setting the duplex mode to full duplex or both ends of the connection so if this does not work running half duplex on both ends is preferred over a duplex mismatches.

if ports are assigned to different vlans they cannot communicate even if two hosts are in the same ip network

arp -d windows command

if the network administrator or the systems administrators want to repopulate the cache with an updated information

Step 6: Verify the Transport Layer

if the network layer appears to be functioning as expected but users are still unable to access resources then the systems administrator or the network administrator must begin troubleshooting the upper layers.

in many internet based networks point-to-point connections are now the norm and the use of hubs and the associated half duplex operation is becoming less common so this means that most ethernet links today operate in full duplex mode and while collisions were normal foreign ethernet link collisions today often indicate that duplex negotiation has failed or the link is not operating in the correct duplex mode

Policy-based SDN

includes additional Policy layer that operates at a higher level of abstraction.

Syntax

includes types of brackets (), [], {}, the use of white space or indention, quotes, commas, etc.

Controller Open SDN Controller

is a commercial distribution of openDaylight

API

is a standardized definition of the proper way for an application to request services from another application. -is a set of standard request

OpenFlow

is a widely implemented southbound API.

Layer 3 Switch and CEF: CEF (cisco express forwarding)

is an advanced layer 3 IP switching technology that enables forwarding of packets to occur at the data plane without consulting the control plane.

Automation

is any process that is self-driven that reduces and potentially eliminates the need for human intervention

Application Policy Infrastructure Controller (APIC)

is considered as the brains of the ACI architecture

Restful web service

is implemented using HTTP. It is a collection of resources with four defined aspects:

Data known as Object

is one or more key/value pairs enclosed in braces {}.

XML

is one or more type is human readable data format used to store, transfer, and read data by applications.

APIC

is positioned between the APN and ACI-enabled network infrastructure.

Control Plane and Data Plane: Management plane

is responsible for managing a device through its connection to the network

Orchestration

is the arranging of automated tasks that results in a coordinate process or workflow

IBN

is the emerging industry model for the next generation of networking

Policy-based SDN

is the most robust among the types of SDN, wherein it provides a simple mechanism to control and manage policies across the entire network

Hyphen

is used to separate each element in list

show interfaces

is useful when troubleshooting performance-related issues and hardware is suspected to be at fault.

Overlay

is where encapsulation protocols like IPsec and CAPWAP occur.

Step 5: Verify Correct Path

it is often necessary to verify the path of the destination network

SDN controller

it orchestrates or mediates and facilitates communication between application and the network elements

Array (in JSON)

key contains more than one value. It is an ordered list of values.

Simple Network Management Protocol (SNMP)

lets administrators manage nodes on an IP network

Overlay

limits the number of devices the network administrator must program and provides services and alternative forwarding methods not controlled by the underlying physical devices

Configuration Management Tools

make use of RESTful API requests to automate tasks and can scale across thousands of devices.

SDN

management of the control is moved to a centralized SDN controller.

IEEE 802.3ab Gigabit Ethernet standard

mandates the use of auto negotiation for speed and duplex and practically all Fast Ethernet NICs also use auto negotiation by default.

RPC

means that another system executes some code and returns the information

API call

message from the requesting application to the server where data resides

Step 4: Verify Default Gateway

misconfigured or missing default gateways

Default gateway

needs to be configured if you want to reach hosts that are beyond the local network.

network management station (NMS)

network administrators use SMNP to monitor and manage network performance, fins and solve network problems, and perform queries for statistics

Intent Based Networking (IBN) and Cisco DNA Center

o Builds on Software-Defined Network (SDN), transforming a hardware-centric and manual approach to designing and operating networks to one that is software-centric and fully automated (from hardware-centric and manual to software-centric and automated) o Captures business intent and uses analytics , machine learning, and automation to align the network continuously and dynamically as business needs change o Captures and translates business intent into network policies that can be automated and applied consistently across the network

REST API

o Defines a set of function s developers can use to perform requests and receive responses via HTTP Protocol (GET and POST) o Refers to a style of software architecture that has many underlying characteristics and governs the behavior of the clients and servers

There are some of the benefits of automaton:

o Machines can work 24 hours a day without breaks, which results in greater output o Machines provide a more uniform product o Automaton allows the collection of vast amounts of data that can be quickly analyzed to provide information which can help guide an event or process o Robots are used in dangerous conditions such as mining, firefighting, and cleaning up industrial accidents. This reduces the risk to humans. o Under certain circumstances, smart devices can alter their behavior to reduce energy usage, make a medical diagnosis, and improve automobile driving safely

Agent-based Configuration Management

o is pull-based o The agent on the managed device periodically connects to the master for each configuration information o Changes done by the master, pulled down and executed by the device

Agentless Configuration Management

o is push based o Configuration script is run on the master o The master connects to the devices and executes the tasks in the script o Only Ansible is agentless

Collisions

often indicate duplex mismatches

Value

on the right; is the data itself and can be character, string, number, list or another type of data

Other Components

other components includes Interface to the Routing System (I2RS), Transparent Interconnection of Lots of Links (TRILL), Cisco FabricPath (FP), and IEEE 802.1 aq Shortest Path Bridging (SPB).

APIC-EM

provides a single interface for network management

Open APIs or Public APIs

publicly available and can be used with no restrictions

Administrator

reduce the time it takes to diagnose and solve the problems

Key & Values

separated by colon (:)

Multiple key/value pairs

separated by commas

Web Service

service that is available over the internet, using the World Wide Web

ssh

should be used to remotely manage and configure devices

Step 1: Verify Physical Layer

show interfaces command -this step is used if the problem is in the given device or the hardware

Policy-based SDN

similar to controller-based SDN where a centralized controller has a vie of all devices in the network.

Cisco ACI

simplifies the way data center networks are created.

API

software that allows other applications to access its data or services.

Data Formats: HTML (Hypertext Markup Language)

standard markup language for describing the structure of web pages

Keys

strings with quotation marks " ". Ex. "name" : "GigabitEthernet0/0/0"

Data format

supported by the web service (JSON, YAML, XML)

Set of operations

supported by the web service using HTTP methods

Think

the ability to connect a series of related information together and then use them to alter the course of action

Client-server

the client handles the front end and the server handles the back end. Either can be replaced independently of the other

Traditional and SDN Architectures

the control plane and data plane functions occurs in the same device.

show ipv6 interface

to check if the router is enabled as an all ipv6 router

show run

to display the DNS configuration information on the switch-router

ipv6 unicast-routing

to enable the router as an ipv6

show vlan

to validate bill and assignments on a switch

APIC

translates the applicable requirements into a network configuration to meet those needs.

IBN has three essential functions:

translation, activation, and assurance These functions interact with the underlying physical and virtual infrastructure

Configuration Management Tools

typically include automation and orchestration

Partner APIs

used between a company and its business partners or contractors to facilitate business between them

ping or telnet

used in verifying DNS

Step 8: Verify DNS

used to resolve issues or to resolve ip addresses into issues or to resolve ip addresses into names

ping and traceroute

used to verify end-to-end connectivity

OpenFlow

was developed at the stanfordv university to manage traffic between routers, switches, wireless access points and the controller.

Automation

when a tool automatically performs a task

show mac address-table

when the company has reorganized the cables connected to switch 1 but then users cannot access the support desk or could no longer reach devices that are outside their network, they use this command to check

when there is a problem with end-to-end connectivity you can use the bottom-up approach when there is no end-to-end connectivity

Python

· APIs can also be called from within a Python program This allows for possible automation, customization, and App integration of the API

Developer Web Site

· Developers often maintain websites that include information about the API, parameter information, and usage examples. · May also allow user to perform the API request within the developer web page by entering in the parameters and other information

Representational State Transfer (REST)

· Does not require a XML · Uses HTTP LS verbose; is easier to use than SOAP

Postman

· Is an application for testing and using REST APIs. · Contains everything required for constructing and sending REST API requests, including entering query parameters and keys · Allows you to connect, collect, and save frequently used API calls in history or as query parameters and keys · Excellent tool for learning how to construct API requests and for analyzing the data that is returned from the API

Data formats used in many applications including network automation and programmability:

· JSON (JavaScript Object Notation) · XML (eXtensible Markup Language) · YAML (YAML Ain't Markup Language)

Partner APIs

· Must have a license or other form of permission to use the API

Representational State Transfer (REST)

· Refers to a style of software architecture and it has become popular due to its performance, scalability, simplicity and reliability · Most commonly used

Network Operating Systems

· Using protocols such as NETCONF (Net Configuration) and RESTCONF, network operating systems are beginning to provide an alternative method for configuration, monitoring, and management

Simple Object Access Protocol (SOAP)

· designed by Microsoft in 1998 · Considered slow to parse complex and rigid

Automation, Network Virtualization, Troubleshooting IP Connectivtity

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