Valid ECP-206 Test Answers & Ericsson ECP-206 Exam PDF [Q32-Q48]

Explanation
P routers forward packets based on the LSP label. The LSP label is the label that corresponds to the label-switched path (LSP) that is established between two PE routers in an MPLS network. The LSP label is also called the outer label or the transport label, because it is used to transport packets across the MPLS core network. P routers are also called LSRs (label switch routers) or transit routers, because they switch packets based on their labels or remove the labels. P routers do not need to look at the IP header or any other information in the packet, except for the top label in the label stack. P routers perform one of three possible operations on labels: swap, pop, or PHP (penultimate hop popping). In a swap operation, the label is swapped with a new label, and the packet is forwarded along the path associated with the new label. In a pop operation, the label is removed from the packet, and the packet is forwarded based on its IP header or another label in the stack. In a PHP operation, the label is removed from the packet at the last P router before reaching the egress PE router, and the packet is forwarded without any label to the egress PE router.
The LSP label is different from other types of labels that may be used in MPLS networks, such as VPN labels or service labels. These labels are used to identify different VPNs or services that run over MPLS networks, such as Layer 2 VPNs, Layer 3 VPNs, traffic engineering, or QoS. These labels are also called inner labels or payload labels, because they are related to the payload of the packet. These labels are not used by P routers for forwarding decisions, but only by PE routers for delivering packets to their destinations.
Therefore, the answer is C.
References: Ericsson IP Networking – Routing Protocols, MPLS Fundamentals: Forwarding Labeled Packets – Cisco Press, MPLS Labels and Devices – NetworkLessons.com, Multiprotocol Label Switching – Wikipedia, VPN Packet Forwarding > MPLS/VPN Architecture Overview | Cisco Press, Basic concepts – Hewlett Packard Enterprise

Explanation
For IP destinations not found in the IS-IS Level 1 database, the Level 1 router must forward packets to the nearest Level 1-Level 2 router with the attach bit set. The attach bit is a flag in the IS-IS Level 1 LSP that indicates that the router is also a Level 2 router and can reach destinations outside the Level 1 area. The Level
1 router will install a default route pointing to the nearest Level 1-Level 2 router with the attach bit set. This way, the Level 1 router can forward packets to other areas without having to maintain a full Level 2 database. References: Ericsson IP Networking – Routing Protocols, Configure Attach Bit Set – Cisco

Explanation
The correct abbreviation for the IP address BFEA:DACA:0000:0000:9390:0000:0000:D91 is BFEA:DACA::9390:0:D91. IPv6 addresses are represented in hexadecimal notation, with eight 16-bit segments separated by colons. To simplify the address representation, IPv6 supports two types of abbreviations. The first abbreviation allows us to skip leading zeros within a segment, while the second abbreviation allows us to drop one or more consecutive segments that contain only zeros, using a double colon (::) instead. However, the double colon can be used only once in an address, to avoid ambiguity34.
References: IPv6 Address Types, Notation, and Structure Explained, IPv6 address – Wikipedia

Explanation
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

Explanation
The CLI command to obtain the software version in Ericsson Router 6000 products is show version. This command displays information about the software release, the hardware model, the serial number, the uptime, and the boot image of the router. References: [ERICSSON SMARTEDGE 600 HARDWARE MANUAL Pdf Download | ManualsLib], Ericsson Router 6000 Series – Ericsson

Explanation
LDP relies on IGP for all routing-related decisions. LDP is a protocol that distributes labels in an MPLS environment, but it does not perform any routing functions. LDP uses the underlying routing information provided by an IGP, such as OSPF or IS-IS, to forward label packets. LDP and IGP do not exchange their databases at regular intervals, but rather use hello messages to maintain adjacencies and sessions. References: Ericsson IP Networking – Routing Protocols, Label Distribution Protocol – Wikipedia

Explanation
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

Explanation
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

Explanation
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

Explanation
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

Explanation
A BGP session is established between two routers by sending a unicast OPEN message. BGP uses TCP as its transport protocol, which means that before exchanging any BGP information, a TCP connection must be established between the routers. The TCP connection uses port 179 as both source and destination port. After establishing a TCP connection, each router sends an OPEN message to its neighbor, containing parameters such as BGP version number, AS number, hold time, BGP identifier, and optional capabilities. The OPEN message also serves as a keepalive message for BGP. If both routers agree on these parameters, they proceed to exchange UPDATE messages containing routing information and establish a BGP session.
A BGP router does not send a NOTIFICATION message to establish a session, but rather to terminate a session due to an error or a manual shutdown. A BGP router does not send a CONNECT message, as this is a TCP state, not a BGP message. A BGP router does not send a multicast HELLO packet, as this is an OSPF message, not a BGP message. References: BGP Neighbor States > BGP Fundamentals | Cisco Press, Demystifying BGP Session Establishments – Packet Pushers, The TCP/IP Guide – BGP Connection Establishment: Open Messages

Explanation
The action that will influence BGP route selection within your AS is changing the default value of the local preference attribute. The local preference attribute is used to indicate the preference of a path among multiple paths learned from different external BGP neighbors or autonomous systems (ASes). The higher the local preference value, the more preferred the path is within your AS, and vice versa. The default value of local preference is 100, but you can change it using route maps or other configuration methods on your BGP routers. References: Ericsson IP Networking – Routing Protocols, BGP Attributes and Path Selection, BGP Local Preference Attribute: Controlling Traffic Like a Pro

Explanation
Two statements that are correct for LDP are:
LSRs send UDP hello messages for neighbor discovery. LDP is a protocol that distributes labels for MPLS forwarding along the shortest path calculated by an IGP. LDP uses two types of messages:
discovery messages and session messages. Discovery messages are used to discover and maintain adjacency with other LSRs that support LDP. Discovery messages are sent as UDP datagrams to the well-known multicast address 224.0.0.2 (all routers on this subnet) on port 64634.
LSRs use TCP to negotiate LDP session parameters. Session messages are used to establish, maintain, and terminate LDP sessions between LSRs. Session messages are also used to exchange label mappings, notification messages, and keepalive messages. Session messages are sent as TCP segments to port
64634.
References: Ldp | Microsoft Learn, Label Distribution Protocol – Wikipedia

Explanation
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

Explanation
Two statements that are true about router node hardening are:
Any unnecessary services should be disabled within each context. Router node hardening is a process of securing a router from unauthorized access and attacks by applying various configurations and policies.
One of these configurations is to disable any services that are not needed for the router’s functionality or purpose, such as telnet, ftp, http, etc. This reduces the attack surface of the router and prevents potential exploits of these services91.
Enabling syslog ensures system events are logged to a remote server. Syslog is a protocol that allows a router to send system messages and events to a remote server for logging and analysis. By enabling syslog on a router, network administrators can monitor the router’s activity and performance, troubleshoot problems, detect anomalies, and audit security events101.
References: Cisco Router Hardening Step-by-Step | SANS Institute, Security Hardening Checklist Guide for Cisco Routers/Switches in 10 Steps, CCNA SEC: Router Hardening – Cisco Press

Explanation
The statement that accurately defines an Autonomous System (AS) is that an AS is a set of routers under a single administration, using an interior gateway protocol and common metrics to route packets within the AS.
An AS is a logical grouping of networks that share a common routing policy and operate under a single administrative authority. An AS can be a single network or a collection of networks that are interconnected by routers. An AS uses an interior gateway protocol (IGP), such as OSPF or IS-IS, to exchange routing information within the AS. An IGP uses common metrics, such as hop count or bandwidth, to determine the best path to each destination within the AS. An AS also has a unique number assigned by IANA, called an AS number (ASN), which identifies the AS in interdomain routing .
References: [Autonomous system (Internet) – Wikipedia], [What Is an Autonomous System? – Cisco]

Explanation
The device that will fragment IPv6 packets is the source host. Fragmentation is a process of dividing a large packet into smaller pieces that can fit the maximum transmission unit (MTU) of the network link. In IPv4, fragmentation can be performed by either the source host or any intermediate router along the path. However, in IPv6, fragmentation is only allowed at the source host, and routers are not allowed to fragment packets. This reduces the processing overhead and complexity at routers and avoids potential fragmentation attacks. If a router receives an IPv6 packet that is too large for the next-hop link, it will drop the packet and send an ICMPv6 Packet Too Big message back to the source host56.
References: IPv6 address – Wikipedia, IPv6 Fragmentation – Cisco