DevNet Associate (Version 1.0) – Practice Final Test Online

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A she-bang is the pound sign (#) followed by an exclamation mark (!) and designates the path to the command interpreter. In this case, the interpreter is bash and bash will be used to interpret the script that follows.

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Edge clouds are located as close to the user as possible. Having computing power at the network edge is a benefit for internet of things devices such as cameras, industrial automation equipment, and autonomous vehicles.

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Because most code developers are not security experts, it is not uncommon to have security vulnerabilities inadvertently written into applications. To help mitigate this threat, there are code scanning tools that a developer can use to look for any well-know security issues embedded into the code. Examples of such tools are Bandit, Brakeman, and VisualCodeGrepper.

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Once a script is created, use the Build Now Jenkins menu option to run the job. If the script is done correctly, then the Stage View should show three green boxes. If errors are found, check the script for errors.

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SQL injection is a basic web application attack technique which, if successful, can delete or change sensitive data or reveal it to the attacker. There are several methods to mitigate the threat of SQL injection such as the use of parameterized database queries, database firewalls, and whitelist input validation.

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Because of the deterministic nature of the hash function, hashed passwords are not unique. The same password always produces the same hash even if the password is created by different users. The salting process adds random data to the input of the hash function to guarantee a unique, nondeterministic output.

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There are three types of version control systems:

• Local version control system
• Centralized version control system
• Distributed version control system

The local version control system stores the delta between the two versions of the file, as opposed to the file itself. When the user wants to revert to the previous version of the file, the delta is reversed to get to the requested version.

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The Software Development Life Cycle (SDLC) is the process of developing software from concept to final product. The process consists of six phases, with each phase using the results of the previous phase as input. The phases are ordered as follows: (1) requirements & analysis, (2) design, (3) implementation, (4) testing, (5) deployment, and (6) maintenance.

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The first phase of the SDLC is the requirements and analysis phase. In this phase the product owner and qualified team members, using feedback from potential customers, gather the requirements for the software to be built.

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The command that you would use for the first copy of an existing Git repository is git clone .

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JSON objects are unordered sets of name/value pairs that begin and end with curly braces { }.

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In Python, classes are a means of bundling data storage and functionality in a single structure. Each class declaration defines a new object type. A class is defined with the class Class_Name() command.

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In YAML the data-structure hierarchy is maintained by outline indentation.

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There are six phases in the SDLC process.

• Requirements & analysis : The product owner and qualified team members gather the requirements for the software to be built.
• Design: Software architects and developers design the software based on the provided software requirement specification document.
• Implementation : Developers take the design documentation and develop the code according to that design.
• Testing : Test engineers take the code and install it into the testing environment so that they can follow the test plan.
• Deployment : The software is installed into the production environment.
• Maintenance : The development team provides support for customers and works on software improvements.

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The command python -V can be used from a command or terminal window to view the Python version installed on the system.

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Firepower Management Center can run on VMware vSphere or Amazon Web Services (AWS). It can also run on a range of physical devices including the Cisco FMC series.

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Cisco Finesse has REST APIs and JavaScript APIs that can be used to build fully customized agent desktops, integrate contact center functionality into applications, and integrate applications into the Finesse agent and supervisor desktop.

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In order to provide API access for an organization, API access must first be enabled within the GUI, under Organization > Settings . After the API is enabled, an API key must be generated within the My Profile page.

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The Intersight REST API enables a user to access the Management Information Model. The Intersight API accepts and returns messages that are encapsulated through JavaScript Object Notation (JSON) documents and uses HTTP over TLS as the transport protocol.

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Most SDKs are packages that require installation and are integrated with libraries, documents, and code examples. APIs are essentially a documented set of URIs that act as an interface for a service.

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YANG, an acronym for Yet Another Next Generation, is a data modeling language used to model configuration and state data manipulated by the Network Configuration Protocol (NETCONF), NETCONF remote procedure calls, and NETCONF notifications.

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Place the options in the following order: Application Includes protocols that provide specific functionality to a variety of end user applications. Provides the interface between applications and the underlying network. Presentation Compresses the data in a way that can be decompressed by the destination device. Ensures that data from the source device can be interpreted by the appropriate application on the destination device. Session Restarts dialogs between source and destination applications when they are disrupted. Handles the exchange of information to initiate dialogs between source and destination applications.

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The 12-bit VLAN identifier is part of the 4-byte Tag field of an 802.1Q Ethernet frame.

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If the network NTP master cannot reach any clock with a lower stratum number, the system will claim to be synchronized at the configured stratum number, and other systems will be willing to synchronize to it using NTP.

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There are three elements that make up an IPv6 global unicast address. A global routing prefix which is provided by an ISP, a subnet ID which is determined by the organization, and an interface ID which uniquely identifies the interface interface of a host.

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The data link layer describes media access and physical addressing. The encoding of a MAC address on a NIC places it at that layer. Ports and cables are placed at the physical layer of the OSI model. IP addresses are placed at the network layer. The TCP/IP protocol stack describes a different model.

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Firewall products come packaged in various forms. These products use different techniques for determining what will be permitted or denied access to a network. They include the following: + Packet filtering – Prevents or allows access based on IP or MAC addresses + Application filtering – Prevents or allows access by specific application types based on port numbers + URL filtering – Prevents or allows access to websites based on specific URLs or keywords + Stateful packet inspection (SPI) – Incoming packets must be legitimate responses to requests from internal hosts. Unsolicited packets are blocked unless permitted specifically. SPI can also include the capability to recognize and filter out specific types of attacks, such as denial of service (DoS)

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DNS uses port 53 and translates URLs to IP addresses. SMB provides shared access to files and printers and uses port 445. Port 80 is used by HTTP. HTTP is a protocol used to communicate between a web browser and a server.

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The two types of DevNet Sandboxes include always-on and reserved. An “always-on” sandbox is available to anyone and typically provides read-only access. A reserved Cisco DevNet Sandbox has shared resources with a quota setting and uses a VPN connection so that traffic to and from the sandbox and development environment is protected.

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Case-based tickets provide 1-on-1 support for certain Cisco APIs. The response time is commonly 1 business day and the cost varies based on the amount of case-based tickets purchased.

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When working in a leaming environment or community-based environment, remember never to use any personal tokens or credentials in the sandbox. Also, do not use tokens or credentials provided in a course or online community in a production environment. It is important to be protective of tokens, passwords, and other identifying information in development environments.

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DevNet provides a catalog of free, self-paced online tutorials called Learning Labs.

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There are a total of ten developer forums on the Cisco Developer Community: Developer Networking Developer Collaboration Developer Security Developer Data Center Developer Intemet of Things Developer Cloud Developer Services Developer Mobility Developer Analytics and Automation Software Developer DevNet Site

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There are commonly three benefits of infrastructure automation: Speed Repeatability The ability to work at scale, with reduced risk

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Puppet and Chef both require the use of an agent, which is used to reterieve information and make desired changes.

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There are many ways to configure remote systems using scripts. However, scripts should be delivered to a remote system through the use of secured protocols or services or both.

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A Service Level Indicator or SLI is a real-world benchmark metric used to determine Service-Level Objectives (SLOs).

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Self-service or “platforms on demand” speeds up all phases of development by using cloud resources that can be available within hours or minutes of needing them.

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In the ansible webservers -m ping command, the parameter ping is an Ansible module invoked by the switch -m

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Most common HTTP status codes include: 200 – OK (using GET or POST to exchange data with an API successfully) 201 – Created (creating resources by using a REST API call successfully) 400 – Bad Request (The request from the client is failed due to client-side issue.) 401 – Unauthorized (The client is not authenticated to access site or API call.) 403 – Forbidden (The access request is not granted based on the supplied credentials.) 404 – Not Found (The page requested at HTTP URL location does not exist or is hidden.)

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SOAP architecture has three characteristics: Independent – different applications can communicate with one another Extensible – extensions can be added to SOAP because it is an application of XML Neutral – SOAP can use a variety of protocols including HTTP, SMTP, TCP, UDP, or JMS

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A REST API request can provide an API key in a few different ways including query string, header, body data, and cookie. In this case, the API key is provided through the query string that is preceded with a symbol ? .

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When the protocol used within the URI is HTTPS, the connection will perform an SSL handshake between the client and the server for secure authentication. This handshake needs to be successful before the REST API request is even sent to the API server. However, because the SSL is self-signed, it would not pass the SSL verification with a CA. In the case of learning and practicing on a local resource, the SSL verification can be turned off by the “verify = False” parameter.

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REST APIs are the short name for Representational State Transfer Webservice APIs. They follow the REST architectural style and communicate over HTTP. REST API requests and responses can use many different data formats; it is not mandatory to use JSON. It is also not mandatory for requests or responses to contain data. Data is provided when applicable. Communication using REST APIs is stateless.

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An API rate limit allows a web service to control the number of requests made in a defined amount of time and is a best practice to use for public and unrestricted APIS. Benefits of using rate limits include the following: Avoids a server overload from too many requests at once Provides better service and response time to all users Protects against a denial of service (DoS) attack

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For security reasons, most REST APIs require authentication to prevent random users from being able to create, update, or delete information incorrectly or maliciously. Basic Authentication, Bearer Authentication, and API Key are authentication mechanisms used by REST APIs. OAuth is an authorization mechanism

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An API rate limit allows a web service to control the number of requests made in a defined amount of time and is a best practice to use for public and unrestricted APIs. Benefits of using rate limits include the following: Avoids a server overload from too many requests at once Provides better service and response time to all users Protects against a denial of service (DoS) attack

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A container is an isolated environment where containerized applications run. It contains the application and all dependencies needed for the application to run. The containers on a physical server all share the same OS, are isolated from each other, and leverage the kernel of the host operating system to allow for quick starts.

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Network Address Translation (NAT) is a technology that is implemented within IPv4 networks. One application of NAT is to use private IP addresses inside a network and use NAT to share a few public IP addresses for many internal hosts. In this way it provides a solution to slow down the IPv4 address depletion. However, since NAT hides the actual IP addresses that are used by end devices, it may cause problems for some applications that require end-to-end connectivity.

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A switch builds a MAC address table of MAC addresses and associated port numbers by examining the source MAC address found in inbound frames. To forward a frame onward, the switch examines the destination MAC address, looks in the MAC address for a port number associated with that destination MAC address, and sends it to the specific port. If the destination MAC address is not in the table, the switch forwards the frame out all ports except the inbound port that originated the frame.

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With the IPv4 address, a subnet mask is also necessary. A subnet mask is a special type of IPv4 address that coupled with the IP address determines the subnet of which the device is a member.

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Cisco Umbrella serves as a first line of defense for an organization by blocking requests to malicious internet destinations.

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In a formal code review, developers have a series of meetings to review the whole codebase and go over the code line by line, discussing each one in detail. The formal code review process promotes discussion among all of the reviewers.

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This item is based on information contained in the presentation. A DoS (denial of service) attack prevents users from accessing network resources. A brute force attack attempts to guess the password of an account. A zero day attack is the first occurrence of a previously unknown virus or other malware.

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The HTTP header string is a cache control directive that indicates that (1) the response content can be saved by any cache and (2) the cached content will expire in 3600 seconds unless it gets refreshed before it expires.

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Bash is the name of the default script engine that lets you do things from the command line. It is the default shell for most Linux distributions.

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• manipulation of resources through representations: The client receives a representation of the resource from the server that must contain enough data for the client to handle the resource.
• hypermedia as the engine of application state: The server must include additional actions and resources available for the client to access supplemental information about the resource.
• independence of client and server: (Not use)
• notification of cache capability: (Not use)
• self-descriptive messages: Each message must contain all the information for the recipient to process.
• identification of resources: A resource must be identified in the request as the individual object.

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With the Test-Driven Development process, testing code is written before application code. The application code is then created with the single purpose of being able to barely pass the testing code.

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Parsing is the process of analyzing a message, separating it into component parts, and understanding the purpose of it in context.

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The nslookup command is used to obtain an IP address for a specific domain name by querying a DNS server. The desired domain name follows the command and optionally the IP address of a particular DNS server.

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A virtual local-area network (VLAN) is a separate Layer 2 network that has its own broadcast domain. A Layer 3 device such as a router or multilayer switch is required to communicate between VLANs.

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If a large amount of return data is expected, the client can request that the return data be compressed with a specific compression algorithm. To request a data compression, the request must add the Accept-Encoding field to the API request header. For example, a header string of “Accept-Encoding: gzip” tells the server to compress the return data using the gzip algorithm. If the server fulfills the compression, it will send the response back with the compressed data and add the Content-Encoding field to the response header. The value of the Content-Encoding is the type of compression that was used.

Hint

• resolves a host name to an IP address –> DNS
• facilitates network and device monitoring –> SNMP
• extends the lifetime of IPv4 addresses –> NAT
• provides IP address configuration information –> DHCP
• provides accurate clock-related information –> NTP

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A = Authorization B = Content-Type C = application/json D = max E = 100 F = url G = headers=headers

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A : import json B : “username”:”cisco”, “password”:”cisco123!” C : resp.status_code D : resp.json() E : serviceTicket

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RPC, SOAP, and REST are the three most popular types of API architectural styles. They all support the client-server model. RPC and REST can use XML or JSON. SOAP uses XML. REST requires that the communication between the client and the server remains stateless.

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Cisco IOS XE is the next-generation programmable platform. Both NETCONF and RESTCONF are supported. Their connections should be authenticated using AAA credentials. RESTCONF runs over HTTPS which is enabled by the command ip http secure-server . The CLI command to enable RESTCONF is simply restconf . NETCONF uses SSH as a transport. NETCONF supports both running and candidate data stores, whereas RESTCONF supports only a running datastore.

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DevNet provides ways for community members to share with each other. These are called Exchanges. In the Code Exchange site, users can submit a repository that they have found useful for any technology area. Users can search for any keyword in the repository and get a list of results.

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The Cisco UCS Manager products provide scalability by integrating many components of a data center. The different management products directly relate to the number of servers being managed:

• Cisco Integrated Management Controller (CIMC) can manage a single physical server.
• Cisco UCS Manager (UCSM) can manage up to 160 physical servers.
• Cisco UCS Central (UCSC) can manage up to 10,000 physical servers.

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User Data Services (UDS) is a REST-based API that provides a mechanism for inserting, retrieving, updating, and removing data from the Unified Communication configuration database. The UDS API is designed to enable end users to update and configure personal settings.

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When a Git merge is performed, the source branch is untouched and only the target branch is modified.

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The distributed version control system is a peer-to-peer model that clones the full repository to client systems and allows every individual to work on any file, even at the same time.

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• Dashboard API: a RESTful service for device provisioning, management, and monitoring
• Location Streaming API: an HTTP POST method providing Wi-Fi and Bluetooth client location information
• Webhook API: a real-time notification system for network alerts, covering events and network health
• External Captive Portal (EXCAP) API: an API that enables an organization to build out custom engagement models at Wi-Fi access points
• MV Sense API: a combination of REST APIs and realtime MQTT stream supporting oversight of a physical space

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PyATS uses Python for low-level code, but relies on Genie, a higher-level library system, in order to interact with network devices and perform testing.

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• Service Manager: maintains device dependencies and provideds a service self start for triggering diagnostic tests
• Device Manager: deploys configuration changes to multiple devices through the use of distributed transactions
• Configuration Database: provides an internal API for locating network element configurations and automatic support for upgrade and downgrade of configuration data

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Name resolution issues often manifest as lost network connectivity and authentication failures between a network app and a remote server. Common problems include defining the correct DNS server, a missing or incorrect DNS entry, an incorrect hostname, or a configuration issue on the DNS server being used.

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Because server load balancing distributes server requests across multiple servers, the load balancer should be attached to the same switch that the servers are on.

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What are two functions of MAC addresses in a LAN? (Choose two.)

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The term edge computing refers to the practice of placing computing resources as close to the actual sources of data as possible. Deploying computer resources at the edge, can help to avoid high levels of data transfer across the network for performance or security purposes.

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A webhook is an HTTP callback, or an HTTP POST, to a specified URL that notifies a registered application when an activity or event has occurred in one of the resources on the platform. Webhooks enable applications to get real-time data. With webhooks, applications are more efficient because they no longer need to have a polling mechanism.

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Ansible uses an inventory file called hosts that contains device information used by Ansible playbooks. The hosts file begins with an alias for the remote. After the alias, the hosts file specifies three variables that will be used by the Ansible playbook to access the device. These are the SSH credentials Ansible needs to securely access the remote host.

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The error message indicates that the connection to the host cannot be established. The causes could be an internet connection issue, or the domain name of the host cannot be resolved by DNS servers because it is wrong.

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Continuous Integration/Continuous Deployment (CI/CD) is a philosophy for software development that includes automation as part of the process. Continuous integration attempts to eliminate the problem of conflicts that occur when new or updated code is applied to the main application. Even though there is a potential of a bad build being deployed to the users, companies can limit that impact by using a deployment strategy such as a rolling upgrade, canary pipeline, or blue-green deployment.

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In summary, model-driven programmability does the following:

• Provides configuration language that is human-readable
• Is model-based, structured, and computer-friendly
• Includes support for multiple model types, including native, OpenConfig, and IETF
• Uses a specification that is decoupled from transport, protocol end encoding
• Uses model-driven APIs for abstraction and simplification
• Leverages open-source and enjoys wide support

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Cisco VIRL is used to build network simulations and it can duplicate the same code that runs inside actual Cisco products. The native configuration format is called a.virl file, which is a human-readable YAML file.

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With REST APIs, the response code 201 is with the status message of “Created”. It indicates that the request was fulfilled, and the requested resource was created.

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The XML prologue is placed as the first line in an XML file and contains the tag name xml and attributes that provide the version and the character encoding.