Free Practice Questions for Ericsson ECP-206 Exam

An Ethernet switch will forward the frame to all ports when the destination address is FF:FF:FF:FF:FF:FF. This is because this address is the broadcast MAC address, which means that the frame is intended for all devices on the same LAN segment. The switch does not need to look up its MAC address table to find a matching entry for this address, but simply floods the frame out of all ports except the one where it received the frame. This way, the frame reaches every device on the LAN segment, regardless of their MAC addresses. References: Ethernet - Wireshark, Broadcast MAC Address - omnisecu.com

Referring to the exhibit, the correct statement is that the service provider’s P routers are not aware of the customers’ routes. This is because P routers only need to forward MPLS packets based on their labels, without looking into their IP headers or VPN information. The P routers do not have any VRFs configured for the customers, nor do they participate in MP-BGP sessions with other PE routers. The PE routers are responsible for maintaining VRFs for each customer and for exchanging VPN routes with other PE routers using MP-BGP910.

References: Layer 3 VPNs (L3VPN) - Cisco, MPLS VPN - Wikipedia

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 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

Peers recognize each other’s ability to use MP-BGP extensions by advertising the ability using the capabilities field during the session establishment. MP-BGP is an extension to BGP that allows BGP to carry routing information for multiple network layer protocols, such as IPv6, VPNv4, multicast, etc. To support MP-BGP, peers need to exchange their capabilities during the session establishment phase, which consists of three steps: open, keepalive, and update. In the open message, peers can include an optional parameter called capabilities, which indicates what kind of address families and subsequent address families they can support. If both peers agree on a common set of capabilities, they can proceed to exchange routing information for those address families using update messages56.

References: Use of MP-BGP Extensions for IPv6 Interdomain Routing, MP-EBGP Configuration Example - Cisco

In OSPFv2, the route characteristic that is used to determine the best path is the cost. The cost is a metric that represents the link bandwidth, delay, reliability, or other factors. The cost is inversely proportional to the bandwidth, meaning that a higher bandwidth link has a lower cost. The cost of a route is calculated by adding the costs of all links along the path. OSPFv2 uses the following formula to calculate the cost of an interface:

Cost = Reference bandwidth / Interface bandwidth in bps

The reference bandwidth is a constant value that can be configured by the network administrator. By default, it is 100 Mbps. The interface bandwidth is the actual bandwidth of the interface in bits per second. For example, if an interface has a bandwidth of 10 Mbps, its cost would be 100 Mbps / 10 Mbps = 101415.

OSPFv2 does not use jitter, packet loss, or delay as route characteristics to determine the best path. Jitter is the variation in latency or delay between packets. Packet loss is the percentage of packets that are dropped or corrupted during transmission. Delay is the time it takes for a packet to travel from source to destination. These characteristics are not part of the OSPFv2 protocol and are not advertised in OSPFv2 LSAs1617.

References: OSPF Metric cost Calculation Formula Explained - ComputerNetworkingNotes, OSPF Cost – OSPF Routing Protocol Metric Explained - Study-CCNA, Open Shortest Path First - Wikipedia, OSPF Metric = Cost - Cisco

The command that is used to begin making changes to the router settings in an Ericsson Router 6000 is configure. This command enters the configuration mode, where various commands can be used to modify the router parameters, such as interfaces, protocols, services, security, etc. To exit the configuration mode, the command end can be used. To save the changes made in the configuration mode, the command commit can be used56.

References: Router 6000 Series - Ericsson, Ericsson Router 6000 series (6471/6672/6675) Commands for 2G/3G/4G/5G technologies… - YouTube

In the exhibit, the action performed by router R3 for traffic arriving from router R2 towards router R4 is PHP, which stands for penultimate hop popping. PHP is a process in which the penultimate hop router (the router before the egress router) removes the top label from an MPLS packet before forwarding it to the egress router. This reduces the label stack depth of the packet and relieves the egress router from performing a label lookup operation. In the exhibit, router R3 is the penultimate hop for traffic arriving from router R2 towards router R4. Router R3 will perform a PHP operation, removing the top label from the incoming packet before forwarding it to router R478.

References: PHP Tutorial - W3Schools, PHP: Downloads

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