Cisco ENCOR Exam: Network Fundamentals

Implementing Cisco Enterprise Network Core Technologies (ENCOR)

• The exam consists of 35 questions and lasts 120 minutes.
• The exam code is 350-401.

Type 1 Hypervisors

• Benefit: allows creation of virtual networks to interconnect virtual machines in Layer 2 topologies.

Wireless Received Signal Strength Indicator (RSSI)

• Measures how well a device can hear a signal from an access point or router.
• Measured in decibels (dBm) from 0 to -120.
• Closer to 0, the stronger the signal is, which is better for wireless connections.

Cisco SD-Access Data Plane

• Uses Virtual Network Identifier (VNI) to identify a specific virtual network.
• Based on VXLAN technology.

YANG (Yet Another Next Generation) Data Model

• Used to describe data models.

Cisco DNA Center

• Allows management of non-Cisco devices through the use of a Software Development Kit (SDK) that creates Device Packages for third-party devices.
• Application responsible for group-based access control permissions is Policy.

Flexible NetFlow

• Two flow exporters are needed per network device in the flexible NetFlow configuration.

SSO (Stateful Switchover) and NSF (Nonstop Forwarding)

• Ensure redundancy and uninterrupted Layer 3 traffic.
• Must be combined with NSF to support uninterrupted Layer 2 and Layer 3 operations.

HSRP (Hot Standby Router Protocol)

• Ensures that traffic is not disrupted in the event of a hardware failure.
• Uses a virtual MAC address.

Control Plane Policing

• Implemented for SSH and Telnet using specific configuration sets.

QoS (Quality of Service)

• Classification, marking, and policing of traffic are components of QoS.

EEM (Embedded Event Manager)

• Enables OSPF debugging in the event of an OSPF neighborship going down.

Syslog

• Used to send logging messages to a syslog server.
• Requires a specific configuration using a reliable protocol and a specific IP address.

NETCONF

• Used to configure a router.
• Requires a specific configuration to complete the configuration.

Wireless Network Configuration

• A specific configuration is required to provide a splash page for authentication.

EtherChannel

• A channel-misconfig error can be resolved by configuring the same protocol on the EtherChannel on both switches.

LISP (Locator/ID Separation Protocol)

• Map resolver (MR) receives MAP requests, de-encapsulates them, and forwards them to the Mapping Server (MS).
• Used to separate location and identity of network nodes.

Cisco Trustsec

• Enables more access controls for dynamic networking environments and data centers.
• Classifies traffic based on the contextual identity of the endpoint rather than its IP address.

GRE Tunnel

• The output of the show interface tunnel command confirms the configuration of the GRE tunnel.

HTTP/1.1 204 Content

• Returned when the curl -I -X delete command is issued, indicating that the object was successfully deleted.

Intent-Based Networking

• A company can migrate from a traditional campus design to a programmer fabric designer using Cisco DNA Center.### Wireless Networking
• When a wireless client roams between two different wireless controllers, a network connectivity outage is experienced for a period of time. This is caused by a configuration issue where not all controllers in the mobility group are using the same virtual interface IP address.

IP SLA and EEM Applet

• IP SLA can be configured to ping an IP address every 3 seconds to ensure the connection is still up.
• An EEM applet can be configured to shut down an interface and bring it back up when there is a problem with the IP SLA.

JSON Syntax

• A valid JSON syntax example: {'switch': {'name': 'dist1', 'interfaces': ['gig1', 'gig2', 'gig3']}}

Access Control

• To deny Telnet traffic from the loopback interface of one router to the loopback interface of another router, a time-range and access-list can be configured.

TCAM and CAM

• TCAM (Ternary Content Addressable Memory) is used for faster address lookups, enabling fast routing in routers.
• CAM (Content Addressable Memory) is used for building and looking up the MAC address table, enabling L2 forwarding decisions in switches.

Virtualization

• A Type 2 hypervisor runs on top of an operating system and not on the physical hardware directly.
• Examples of Type 2 hypervisors include VMware Workstation and Microsoft Virtual PC.

Cisco Trustsec

• Cisco Trustsec enables more flexible access controls for dynamic networking environments and data centers by classifying traffic based on the contextual identity of the endpoint rather than its IP address.

Mobility

• When a client device roams between wireless LAN controllers that are mobility peers, both controllers have a dynamic interface on the same client VLAN, which is an example of inter-controller roam.

Secondary WLC

• The responsibility of a secondary WLC is to register the LAPs if the primary controller fails.

Intent API

• The Intent API is a Northbound REST API that exposes specific capabilities of the Cisco DNA Center platform.
• It provides policy-based abstraction of business intent, allowing focus on an outcome rather than struggling with individual mechanisms steps.

DHCP Option

• DHCP option 43 provides the CAPWAP APs with the address of the wireless controller(s).
• DHCP option 150 provides the CAPWAP APs with the address of the wireless controller(s).

MED Attribute

• The MED (Multi-Exit Discriminator) attribute is used to influence the route selection process in BGP.
• It is a non-transitive attribute that is sent through ASes to external BGP neighbors.
• A lower MED value is preferred.

AP Coverage Area

• To reduce the AP coverage area, the AP transmit power can be reduced or the minimum mandatory data rate can be increased.

Security Policy

• To terminate all idle-exec sessions in 600 seconds, the absolute-timeout command can be used in the line vty configuration.

AMP4E

• AMP4E (Advanced Malware Protection for Endpoints) has the ability to block ransomware and Microsoft Word macro attacks.

Cisco DNA Center

• The Intent API is a Northbound REST API that exposes specific capabilities of the Cisco DNA Center platform.
• Cisco DNA Center is a solution that provides a single, unified way to manage network devices.

SPAN and RSPAN

• SPAN (Switched Port Analyzer) is a feature that allows monitoring of traffic on a specific VLAN or port.
• RSPAN (Remote SPAN) is a feature that allows monitoring of traffic on a remote VLAN or port.

NAT and PAT

• NAT (Network Address Translation) is a technique that allows multiple devices to share a single public IP address.
• PAT (Port Address Translation) is a technique that allows multiple devices to share a single public IP address and port.

DNS and DHCP

• DNS (Domain Name System) is a system that translates hostnames to IP addresses.
• DHCP (Dynamic Host Configuration Protocol) is a protocol that assigns IP addresses to devices on a network.

Access Point Join Process

• The AP join process can be configured using DNS.
• The AP can obtain the IP address of the WLC using DNS.

Ansible and Chef

• Ansible and Chef are both automation tools used for configuration management.
• Ansible uses YAML to manage configurations and pushes the configuration to the client.
• Chef uses Ruby to manage configurations and the client pulls the configuration from the server.

SD-Access Solution

• In an SD-Access solution, the fabric edge node connects wired endpoints to the SD-Access fabric.

Virtual Machine

• A virtual machine can run multiple virtual servers on the same physical server without having to buy additional hardware.

TLS for Syslog

• TLS (Transport Layer Security) can be used to securely transport syslog messages.
• The default port for syslog over TLS is 6514.

Cisco DNA Center

• Cisco DNA Center supports REST controls at the Northbound API layer.
• YAML output from responses to API calls can be used to configure devices.Here are the study notes:

TTL Exceeded Message

• When the TTL (Time To Live) of a packet expires, the router discards the packet and sends an ICMP Time Exceeded message.
• Routers check the TTL first before processing a packet further.
• If the TTL is zero, the router discards the packet and sends an ICMP Time Exceeded message.

MACsec Technology

• MACsec (IEEE 802.1AE) provides MAC-layer encryption over wired networks.
• It uses out-of-band methods for encryption keying.
• The MACsec Key Agreement (MKA) Protocol provides the required session keys and manages the required encryption keys.

VXLAN Environment

• In a VXLAN environment, the VNID (VXLAN Network Identifier) is used to identify Layer 2 segments.
• The VNID is a 24-bit field that is used to maintain Layer 2 isolation between segments.

OSPF Neighborship

• For an OSPF neighborship to form, the correct network command must be applied to the router.
• The network command specifies the network address and area ID.

RESTCONF Operations

• RESTCONF is a protocol for managing network devices.
• Valid RESTCONF operations include OPTIONS, HEAD, GET, POST, PATCH, and DELETE.

Fabric Border Node

• In a Cisco SD-Access environment, a fabric border node connects the SD-Access fabric to another fabric or external Layer 3 networks.
• It is responsible for routed access and provides connectivity to external networks.

EIGRP vs OSPF

• EIGRP and OSPF are both routing protocols, but they have different characteristics.
• EIGRP supports equal or unequal path cost, while OSPF only supports equal path cost.

SD-WAN Deployment

• In an SD-WAN deployment, the vSmart controller is responsible for distributing policies that govern data forwarding.
• The vSmart controller is a critical component of the SD-WAN architecture.

NTP Security

• Two mechanisms are available to secure NTP: IP access list-based and encrypted authentication.
• NTP security is critical to prevent NTP attacks.

CEF and Process Switching

• CEF (Cisco Express Forwarding) and process switching are two different packet forwarding mechanisms.
• CEF uses the FIB (Forwarding Information Base) and adjacency table to make forwarding decisions, whereas process switching punts each packet to the CPU for processing.