question stringlengths 0 765 ⌀ | answer stringlengths 0 2.39k ⌀ |
|---|---|
What role does the master switch perform in a StackWise stack? | The master switch is elected from the member switches and manages the entire stack as a single unit, continuously updating network topology and routing information across the interconnect. |
How does StackWise simplify configuration and IP management across multiple physical switches? | The entire stack operates with only one IP address for management tasks and uses a single configuration file that is automatically distributed to every switch in the stack. |
What impact does StackWise have on the need for Spanning Tree Protocol (STP)? | Multiple switches in a StackWise stack can form an EtherChannel connection, which eliminates the need for Spanning Tree Protocol. |
What happens when a new switch is added to the stack? | The master switch automatically configures the new unit with the currently running IOS image and the existing stack configuration, so no manual setup is required before it operates. |
How is a switched stack managed, and what is the maximum number of switches it supports? | The stack is managed as a single object with one management IP address to reduce overhead, and it can contain up to nine switches. |
How does using EtherChannel affect Spanning Tree Protocol requirements in this context? | When EtherChannel is utilized, Spanning Tree Protocol (STP) is no longer needed. |
What is the primary purpose and benefit of cloud computing according to the text? | Cloud computing provides remotely accessible, virtualized processing, storage, and computing resources as on-demand services, which increases overall resource efficiency through virtualization. |
What are the primary advantages of cloud computing for a service provider or builder? | Cloud providers benefit from cost reduction, standardization, automation, and easier administration. They also achieve high utilization through virtualized, shared resources and utilize a fall-in-place operations model. |
How does cloud computing benefit end-users regarding resource provisioning and application architecture? | Users gain access to on-demand, self-service resource provisioning and experience fast deployment cycles. Applications become highly available through horizontal scaling, and resources appear centralized without requiring local backups. |
Why is the centralization of resources critical for modern workforces according to the document? | Centralizing resources eliminates the risk of permanent data loss if a physical device is stolen or damaged. It removes the necessity for constant local backups, ensuring that documents and applications remain accessible securely. |
What key benefits does cloud computing provide to consumers? | Cloud computing enables resource sharing, lower operational costs passed to the consumer, computing scaling, and the ability to dynamically add new servers without undergoing traditional procurement and deployment processes. |
How do customer management and control differ across IaaS, PaaS, and SaaS? | IaaS allows the customer to manage most of the network and offers the highest control, SaaS provides no customer management capability, and PaaS sits in the middle of these two extremes. |
What specific capabilities does Infrastructure as a Service (IaaS) deliver? | IaaS delivers computer infrastructure within a platform virtualization environment, providing customers with the greatest level of control and management capability over their allocated resources. |
What is Platform as a Service (PaaS)? | PaaS provides the operating system, network, and a solution stack that allows customers to develop and run applications without managing the underlying infrastructure. Windows Azure is cited as a primary example of this service model. |
How does Software as a Service (SaaS) operate compared to traditional local installations? | SaaS provides the required software, OS, and network hosted by the vendor, allowing customers to access applications over the Internet. This removes the need for users to install software on their own hardware, with Microsoft Office 365 and AWS offerings as common examples. |
What is the primary goal regarding router and switch ports in modern enterprise networks? | The primary goal is to virtualize the physical ports of routers and switches, as they currently remain the only non-virtualized components in traditional network architectures. |
Why is configuring traditional autonomous devices considered cumbersome? | Autonomous devices require individual configuration, maintenance, and monitoring, meaning that translating business requirements into device commands can take weeks or months to deploy across large, complex networks. |
What are the key responsibilities of the data plane in network forwarding? | The data plane is physically responsible for receiving data, looking up the destination interface, and forwarding frames and packets from ingress to egress interfaces. It relies completely on the control plane to supply the necessary information for these forwarding decisions. |
What tasks and protocols are managed by the control plane in traditional networks? | The control plane manages and controls forwarding tables, including routing protocols such as OSPF, EIGRP, RIP, and BGP. It also handles IPv4 ARP, IPv6 NDP, switch MAC address learning, and Spanning Tree Protocol (STP). |
How does Software Defined Networking (SDN) alter the placement of control plane intelligence? | SDN removes control plane intelligence from individual network devices and consolidates it into a centralized controller. This separation of the control and data planes enables automated configuration and device remediation across the network. |
What is the primary purpose of APIs within the SDN architecture? | APIs allow applications to communicate their network requirements to the SDN controller and configure the network without human intervention. They operate as machine-to-machine configuration interfaces, functioning similarly to CLI, SNMP, or GUI tools. |
What are the three architectural layers defined for SDN networks? | The three layers are the data (forwarding) plane, the control plane, and the application plane. The data plane contains physical or virtual devices handling traffic, the control plane hosts the centralized SDN controller, and the application plane holds applications that send requirements to the controller via APIs. |
What are the two primary sets of APIs used in SDN and what is their respective function? | SDN uses northbound and southbound APIs. Northbound APIs deliver services to the application plane, while southbound APIs handle communication between the SDN controller and the network data plane devices. |
What specific capability do southbound APIs provide to network controllers? | Southbound APIs allow controllers to communicate with network elements and programmatically configure the data plane forwarding tables inside routers and switches. |
Why are these communication paths labeled as southbound and northbound? | The terms originate from traditional network diagrams where network gear is drawn below the controller. The downward-facing connection to devices is designated as southbound, and the upward-facing connection to applications is northbound. |
What distinguishes OpFlex from OpenFlow in their approach to network policy implementation? | OpenFlow uses an imperative model that sends detailed, complex instructions to network elements, whereas OpFlex uses a declarative model where the controller sends abstract summary policies for devices to execute using their own control planes. |
What functions does NETCONF perform for network management? | NETCONF is an IETF-standardized protocol that leverages RPC and XML to install, manipulate, and delete device configurations. It is specifically noted that NETCONF modifies configurations but cannot alter a device's forwarding table. |
What is the purpose of northbound APIs in an SDN architecture? | Northbound APIs handle communication between the SDN controller and running applications. They enable a framework where applications can demand and manage specific network setups and configurations. |
What is onePK and how does it assist developers? | onePK is a Cisco proprietary southbound interface that allows developers to inspect or modify network element configurations without needing hardware upgrades. It supports development through SDKs for Java, C, and Python. |
What automated network services are typically provided by Northbound Interface (NBI) applications? | NBI applications provide automated network services including network virtualization, dynamic virtual network provisioning, firewall monitoring, user identity management, and access policy control. |
How does APIC-EM handle API communication when the controller and application are on different systems? | It uses REST (Representational State Transfer), which sends HTTP messages over the network to transfer data between the different hosts. |
What deployment scenarios does Cisco APIC-EM support? | Cisco APIC-EM supports both greenfield deployments for new installations and brownfield deployments for existing or older infrastructure. |
How does APIC-EM interact with devices and applications within the SDN stack? | APIC-EM connects to applications via a Northbound API and to devices or WAN components via a Southbound API that supports protocols like OpenFlow, onePK, and CLI. |
What is the function of the service abstraction layer (SAL) in Cisco APIC-EM? | The SAL is implemented on the southbound interface to communicate with network elements via SNMP and CLI, and it will soon support NETCONF as well. |
How does the APIC-EM API facilitate network discovery and control? | The API is REST-based, allowing administrators to manage the network using HTTP methods such as GET, POST, PUT, and DELETE with JSON and XML syntax. |
What requirement must network devices meet to be managed by the APIC controller? | Devices must be ACI-specific and require a special NX-OS or ASR IOS version that includes the necessary southbound APIs to communicate with the APIC controller. |
What is the Zero-Touch Deployment feature in APIC-EM? | It automatically discovers new network devices using the controller scanner and configures them without manual intervention. |
How does the Path Trace feature assist in network troubleshooting? | It visually maps the exact route packets take from a source to a destination, highlighting any interfaces where ACLs may be blocking the traffic in a GUI output. |
What is the primary function of the APIC-EM Policy Manager? | It translates high-level business policies into device-specific network policies and enforces them for individual users across wired and wireless networks at scheduled times. |
Which Cisco service does APIC-EM integrate with to track user identities and endpoints? | It integrates with the Cisco Identity Service Engine (Cisco ISE) through its Identity Manager component to exchange endpoint and user information. |
How does APIC-EM determine the path of a packet through the network? | APIC-EM discovers the network topology and uses MAC address tables, IP routing tables, and specified parameters like source/destination addresses or application types to calculate the path and display it with device and interface details. |
What information does APIC-EM provide when a packet is blocked by an ACL? | It identifies the exact interface where the application is blocked and explains the specific reason for the blockage. |
What are the main benefits of Cisco Intelligent WAN (IWAN)? | IWAN allows enterprises to utilize low-cost internet connections for remote locations while preserving application performance, availability, and security. It also offers easy configuration, failover, and redundancy features. |
What hardware specification is required to deploy APIC-EM? | APIC-EM requires a virtual machine with at least 64 gigabytes of RAM to operate properly. |
What are the four main components of Cisco’s Intelligent WAN? | The four components are transport-independent connectivity, intelligent path control, application optimization, and highly secure connectivity. |
How does Cisco IWAN support transport-independent connectivity? | It creates an advanced VPN connection across all available routes to establish a single routing domain, allowing the network to easily multihoming across MPLS, broadband, and cellular connections. |
Which technologies does Cisco IWAN use for application optimization? | Application optimization is achieved through Cisco Application Visibility and Control (AVC) and Cisco Wide Area Application Services (WAAS). |
How does Cisco IWAN utilize intelligent path control to enhance WAN performance? | It employs Cisco Performance Routing (Cisco PfR) to dynamically route traffic based on application service-level agreements and current network conditions, improving delivery and overall WAN efficiency. |
What are the defining characteristics of data traffic on a network? | Data traffic is non-real-time and characterized by being bursty, greedy, drop insensitive, delay insensitive, and relying on TCP retransmits. |
How is voice traffic prioritized and why? | Voice traffic is prioritized using UDP priority because it is real-time, requiring constant predictable bandwidth and known packet arrival times. |
What are the maximum latency and jitter values required for one-way voice traffic? | One-way voice traffic requires a latency of less than or equal to 150 milliseconds and a jitter of less than or equal to 30 milliseconds. |
What are the required network parameters for one-way video traffic? | One-way video traffic requires a latency of less than or equal to 200–400 milliseconds, jitter of less than or equal to 30–50 milliseconds, packet loss of less than or equal to 0.1%–1%, and a bandwidth of 384 Kbps to 20 Mbps or greater. |
What is a trust boundary in the context of network traffic classification? | A trust boundary is the point in the network where packet markings are not necessarily trusted and can be created, removed, or rewritten. It marks the location where packets are classified and marked before entering a trusted domain. |
How does the document define a trusted domain versus an untrusted domain? | A trusted domain consists only of administrator-managed devices such as switches and routers, whereas an untrusted domain includes parts of the network not managed by the administrator, such as end-user PCs and printers. |
Where is the trust boundary typically located within an enterprise campus network? | In an enterprise campus network, the trust boundary is almost always located at the edge switch. |
How does the network handle traffic markings from an untrusted domain at the trust boundary? | Markings on traffic coming from an untrusted domain are usually ignored to prevent end-user-controlled markings from taking unfair advantage of the network QoS configuration. |
What is the primary function of a classifier in QoS? | A classifier is an IOS tool that inspects specific fields within packets to identify traffic types, allowing QoS to determine the appropriate traffic class and treatment. |
What are the structural differences between CoS, ToS, and DSCP? | CoS is a Layer 2 marking using 3 bits known as the PCP in VLAN-tagged frames. ToS uses 8 bits in the IPv4 header (with 3 bits for IP precedence), while DSCP uses a 6-bit code point within the 8-bit DS field in the IP header. |
Why is Layer 3 packet marking considered the most widely deployed marking option? | Layer 3 packet markings with IP precedence and DSCP are the most widely deployed because these layer 3 packet markings have end-to-end significance. |
What is the difference between CoS and TID? | CoS is used for wired Ethernet, while TID (Traffic Identifier) is used in wireless 802.11 frames to describe a 3-bit field in the QoS control field. |
What are the three methods used to classify network traffic? | Traffic classification is performed using markings (existing layer 2 or 3 header settings), addressing (source/destination MACs, IPs, and layer 4 ports), and application signatures through deep packet inspection. |
How does NBAR identify applications and what data structure supports this process? | NBAR performs deep-packet inspection on layers 4 to 7 by examining packet payloads and comparing them against a signature database called a Packet Description Language Model (PDLM). |
What distinguishes passive mode from active mode in NBAR operations? | Passive mode generates real-time statistics on applications by protocol or interface, whereas active mode classifies applications specifically to enable QoS policies such as traffic marking. |
What is the primary function of policers and shapers in traffic management? | Both policers and shapers act as rate limiters that identify traffic issues and manage congestion by applying bandwidth assignments, queuing, dropping, or re-marking to packets. |
How do policers and shapers differ in their response when traffic exceeds the configured rate? | Policers make instant decisions and either drop or re-mark excess traffic without introducing delay, whereas shapers delay the excess traffic to ensure it stays within the contracted rate. |
Why are policers typically recommended for ingress deployment? | They should be placed on the ingress side whenever possible to drop unwanted traffic as soon as it is received rather than processing it further within the network. |
What is the trade-off between using policers and shapers regarding TCP performance and network latency? | Policers do not introduce delay or jitter but can cause significant TCP resends due to higher drop probabilities, whereas shapers reduce TCP resends by delaying traffic but do introduce jitter and delay. |
What is the primary purpose of queuing in congestion management? | Queuing temporarily stores backed-up packets when traffic exceeds available network resources, which helps avoid immediate packet drops and gives traffic time to be processed. |
What are the two types of congestion management tools discussed in the document? | The two types are queuing (buffering) and scheduling. Queuing handles the ordering of packets in output buffers when congestion occurs, while scheduling determines which packet to transmit next regardless of link congestion. |
How does strict priority scheduling work, and what is its primary drawback? | It services high-priority queues completely before processing any lower-priority queues. The drawback is that low-priority traffic may experience queue starvation if high-priority traffic continuously arrives. |
What distinguishes round-robin scheduling from weighted fair scheduling? | Round-robin services queues in a fixed sequence for fairness but causes real-time traffic to suffer, whereas weighted fair scheduling assigns weights to queues to prioritize real-time traffic without causing starvation, though it does not guarantee bandwidth. |
How does packet queuing interact across different network layers when congestion occurs? | Queuing typically occurs at Layer 3 but can also happen at Layer 2 or Layer 1. If a Layer 2 queue fills, data moves to Layer 3 queues, and if the Layer 1 transmit ring queue fills, data is pushed to both Layer 2 and Layer 3 queues, which activates QoS on the device. |
What is First In, First Out (FIFO) queuing? | FIFO is a single queue where packets are processed in the exact order in which they arrived. |
What is tail drop and why is it considered suboptimal for modern networks? | Tail drop refers to the dropping of packets upon arrival when the queues on a receiving interface become full. It is considered suboptimal because it wastes bandwidth, as TCP will continuously resend dropped data until acknowledgments are successfully received. |
What causes TCP global synchronization? | TCP global synchronization occurs when all active TCP flows simultaneously reduce their transmission rates in response to concurrent packet loss. This synchronized reduction leaves a significant portion of the available network bandwidth unused. |
How does Weighted Random Early Detection (WRED) manage traffic during congestion? | WRED is a congestion avoidance mechanism that proactively drops packets before queues completely fill. It applies traffic weights to ensure higher-priority traffic experiences lower loss rates compared to lower-priority traffic during periods of congestion. |
According to the document, what is the functional difference between queuing algorithms and congestion mechanisms? | Queuing algorithms are responsible for managing the front of the queue, while congestion mechanisms handle the management of the back of the queue. |
What happens to bandwidth utilization when TCP flows synchronize after experiencing tail drop? | Tail drop causes TCP to restart traffic flows simultaneously, creating synchronized waves that leave much of the bandwidth unused. |
How many individual switches can be connected to create a StackWise stack? | Up to nine individual switches can be connected together to form a StackWise stack. |
Which QoS mechanisms require detailed understanding for the CCNA exam according to the text? | Detailed knowledge is required for QoS marking, device trust, prioritization for voice, video, and data, shaping, policing, and congestion management. |
What are the key SDN concepts outlined in the Exam Essentials? | The essential SDN concepts include how a controller operates, the distinction between control and data planes, and the roles of northbound and southbound APIs. |
What type of closed-loop path is formed using a StackWise interconnect cable? | A StackWise interconnect cable is used to connect switches to create a unidirectional, closed-loop path. |
How many individual switches can StackWise join into a single logical switching unit? | StackWise can connect up to nine individual switches, joining them together into a single logical switching unit. |
What are the defined bandwidth and latency thresholds for voice traffic? | Voice traffic requires bandwidth roughly between 30 and 128 kbps and should maintain latency below 150 ms. |
Which mechanism is identified as a congestion-avoidance technique in the review questions? | WRED (Weighted Random Early Detection) is listed as the congestion-avoidance mechanism among the provided options. |
On which SDN architecture layer does Cisco APIC-EM reside? | Cisco APIC-EM resides on the Application layer of the SDN architecture. |
In which cloud service model is the customer responsible for managing the operating system, software, platforms, and applications? | This responsibility is assigned to the customer within the IaaS (Infrastructure as a Service) cloud service model. |
Which statement about QoS trust boundaries or domains is true? | An IP phone is widely recognized as a common trust boundary in QoS implementations. |
Which statement about IWAN is correct? | The IWAN allows for transport-independent connectivity between different networks. |
How many bits does the DSCP field constitute in the IP header? | The DSCP field constitutes exactly 6 bits within the IP header. |
How is a switch stack typically managed? | The stack is managed as a single object and is assigned a single management IP address. |
How is the master switch selected within a switch stack? | The master switch is automatically elected from one of the available stack member switches. |
Which cloud computing service model provides the required software, operating system, and network? | Platform as a Service (PaaS) provides the required software, the operating system, and the network. |
According to the text, which item is explicitly NOT considered a benefit of cloud computing for users? | Local backups is identified as a service that is NOT a benefit of cloud computing for a cloud user. |
What is the PDU name at the Data Link layer and what is its main function? | At the Data Link layer, the PDU is called a frame. Its main function is to frame data packets received from the Network layer and provide physical addressing to place packets on the network medium. |
How does the Transport layer ensure reliable communication between hosts? | The Transport layer segments user data and uses virtual circuits to establish a reliable connection between two hosts. |
What is the correct order of PDUs as data moves from higher layers toward the Physical layer? | The correct sequence of PDUs is segments, packets, frames, and bits. |
What is the specified size and representation for a MAC address in the provided answers? | A MAC address is 48 bits, which is equivalent to 6 bytes, and is typically expressed as a hexadecimal number. |
How do hubs and switches differ in their handling of collision and broadcast domains? | A hub creates exactly one collision domain and one broadcast domain, whereas a switch divides the network into many smaller collision domains while maintaining a single large broadcast domain. |
Which OSI layer handles virtual circuit creation, flow control, sequencing, and acknowledgments? | The Transport layer is responsible for these functions, including establishing virtual circuits before data transmission between end stations. |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.