ECP-206 Exam Dumps - Ericsson Certified Associate Questions and Answers

A network operator who wants to make sure voice data is prioritized should assign it to Ethernet traffic class 6. Ethernet traffic class is a term used to refer to the priority code point (PCP) field in the VLAN header of an Ethernet frame. The PCP field is a 3-bit field that can encode up to eight different priority levels, ranging from 0 (lowest) to 7 (highest). The PCP values can be mapped to different types of traffic according to their QoS requirements. The recommended mapping is as follows :

• PCP 0: Best effort (default)
• PCP 1: Background
• PCP 2: Spare
• PCP 3: Excellent effort
• PCP 4: Controlled load
• PCP 5: Video
• PCP 6: Voice
• PCP 7: Network control

Voice data is a type of real-time traffic that requires the highest priority and lowest delay in the network. Therefore, it should be assigned to PCP 6, which corresponds to Ethernet traffic class 6 .

References: [IEEE 802.1Q - Wikipedia], [What is “link aggregation” and how does it benefit your network? | PC Gamer]

The conceptual table created by routing protocols that is used when processing an IP packet is the forwarding information base (FIB). The FIB is a table that contains the bestroutes to reach each destination network prefix, along with the outgoing interface and the next-hop address for each route. The FIB is derived from the routing information base (RIB), which is a table that contains all the routes learned from different routing protocols and sources. The FIB is used by the router to make fast forwarding decisions for each incoming packet, based on its destination address12.

References: Security Hardening Checklist Guide for Cisco Routers/Switches in 10 Steps, VLAN - Wikipedia

The code that is commonly used to assign higher priority to VoIP traffic is EF, which stands for Expedited Forwarding. EF is a per-hop behavior (PHB) defined by the Differentiated Services (DiffServ) model for QoS. EF provides low delay, low jitter, and low loss for real-time applications such as VoIP. EF is marked by setting the DSCP value to 101110, which corresponds to decimal 4678. AF31, which stands for Assured Forwarding class 3 low drop probability, is another PHB defined by DiffServ, but it provides lower priority than EF. AF31 is marked by setting the DSCP value to 011010, which corresponds to decimal 2678. DF, which stands for Default Forwarding, is a PHB defined by DiffServ that provides best-effort service for unmarked traffic. DF is marked by setting the DSCP value to 000000, which corresponds to decimal 078. AF11, which stands for Assured Forwarding class 1 low drop probability, is another PHB defined by DiffServ, but it provides lower priority than EF and AF31. AF11 is marked by setting the DSCP value to 001010, which corresponds to decimal 1078.

References: Differentiated services - Wikipedia, Solved: Cisco VoIP Phone traffic marking - Cisco Community

The protocol that would be used to bundle multiple Ethernet ports into a virtual link with an aggregated bandwidth is LACP, which stands for Link Aggregation Control Protocol. LACP is a protocol that allows two or more devices to negotiate the formation of a link aggregation group (LAG), also known as an EtherChannel or a port channel. A LAG combines multiple physical links into one logical link that provides increased bandwidth, load balancing, and redundancy. LACP is defined in IEEE 802.3ad and 802.1AX standards12.

References: Link Aggregation Control Protocol - Wikipedia, What is “link aggregation” and how does it benefit your network? | PC Gamer

 A reason for using VLANs in an IP network is to isolate hosts within the same IP subnet. VLANs (Virtual LANs) are logical grouping of devices in the same broadcast domain. VLANs are usually configured on switches by placing some interfaces into one broadcast domain and some interfaces into another. Each VLAN acts as a subgroup of the switch ports in an Ethernet LAN. VLANs allow network administrators to group hosts together even if the hosts are not directly connected to the same network switch. By using VLANs, hosts within the same IP subnet can be separated into different broadcast domains, which enhances security, reduces network congestion, and simplifies network management78.

References: 8 Different Types of VLANs in TCP/IP Networks, What is a VLAN? - Study-CCNA

Two roles of the DHCP protocol in a network are:

• It is used by hosts to obtain the IP address and other parameters from the DHCP server. DHCP stands for Dynamic Host Configuration Protocol, which is a protocol that provides automatic and centralized management of IP addresses and other network configuration parameters for devices connected to a network. A host that needs an IP address can send a request to a DHCP server, which will assign an available IP address from a pool and lease it to the host for a certain period of time34.
• It is used to inform hosts about the default gateway. The default gateway is the IP address of the router that connects the host to other networks. The default gateway is one of the parameters that can be delivered by the DHCP server to the host, along with other parameters such as subnet mask, DNS server, domain name, etc. The host can use the default gateway to send packets to destinations outside of its local network34.

References: What Is DHCP? (Dynamic Host Configuration Protocol) - Lifewire, Dynamic Host Configuration Protocol - Wikipedia

There are 8 different priorities available to use in a VLAN header. A VLAN header is a 4-byte field that is inserted into an Ethernet frame to indicate the VLAN membership and priority of the frame. The VLAN header consists of two subfields: the tag protocol identifier (TPID) and the tag control information (TCI). The TCI subfield contains three subfields: the priority code point (PCP), the drop eligible indicator (DEI), and the VLAN identifier (VID). The PCP subfield is a 3-bit field that specifies the priority level of the frame, ranging from 0 (lowest) to 7 (highest). The PCP values can be used to implement quality of service (QoS) mechanisms on bridges and switches12.

References: HTML rt Tag - W3Schools, VLAN 0 Priority Tagging Support - Cisco

Referring to the exhibit, the two Ericsson routers that support the 100GE interface are Router 6675 and Router 6672. The 100GE interface is a high-speed Ethernet interface that operates at 100 gigabits per second. The Ericsson Router 6000 series is a family ofrouters that provide IP transport for mobile and fixed networks. The Router 6675 is a 5G combined access and E-RAN switch with 100GE interfaces and 320Gb forwarding capacity. The Router 6672 is a high-capacity metro aggregation router with 100GE interfaces and 1.6Tb forwarding capacity12.

References: Router 6000 Series - Ericsson, New Ericsson Router 6000 series couples radio and IP transport for 5G future - Global Brands Magazine

The correct ordering (outer to inner) of packet headers in an IP/MPLS packet is Ethernet, MPLS, IP. An IP/MPLS packet is a packet that is encapsulated with an MPLS label stack between the Ethernet header and the IP header. The Ethernet header contains the source and destination MAC addresses and the EtherType field that indicates the type of the payload. The MPLS label stack contains one or more labels that are used for forwarding decisions by the MPLS routers. Each label consists of four fields: label value, experimental bits, bottom of stack, and time to live. The IP header contains the source and destination IP addresses and other information for routing and fragmentation. The order of the headers is important because it determines how the packet is processed by different devices in the network12.

References: MPLS Label Stack - Cisco, MPLS Fundamentals: 3 - MPLS Packet Forwarding

The correct order of DiffServ priority (highest to lowest) for the DiffServ classes: Default Forwarding (DF), Network Control (NC), Assured Forwarding (AF), and Expedited Forwarding (EF) is EF, NC, AF, DF. DiffServ is a QoS model that classifies and prioritizes traffic into different service classes based on the DSCP field in the IP header. The DSCP field is a 6-bit field that can encode up to 64 different per-hop behaviors (PHBs). The DiffServ classes are predefined groups of PHBs that have similar characteristics and requirements. The four main DiffServ classes are:

• EF: This class provides the highest priority and lowest delay for real-time applications such as voice and video. The DSCP value for EF is 101110 or 46 in decimal12.
• NC: This class provides the second highest priority and low delay for network control traffic such as routing protocols and network management. The DSCP value for NC is 110000 or 48 in decimal12.
• AF: This class provides four levels of assured forwarding with different drop probabilities for each level. AF is suitable for applications that require guaranteed bandwidth and delivery assurance, such as web browsing and email. The DSCP values for AF range from 001010 to 011110 or 10 to 46 in decimal12.
• DF: This class provides the lowest priority and best-effort service for applications that can tolerate packet loss and delay, such as file transfer and backup. The DSCP value for DF is 000000 or 0 in decimal12.

References: Differentiated Services - Wikipedia, DSCP - Differentiated Services Code Point - Mpirical