Free and Premium Ericsson ECP-206 Dumps Questions Answers

The router function that advertises external routes in OSPF is ASBR, which stands for Autonomous System Boundary Router. An ASBR is a router that connects an OSPF domain to another routing domain, such as another OSPF domain or a different routing protocol domain. An ASBR can redistribute routes from other routing domains into OSPF as external routes, which are carried in type 5 or type 7 LSAs. External routes have two types: E1 and E2. E1 routes include the cost from the ASBR to the destination, while E2 routes only include the cost advertised by the ASBR34.

References: OSPF External Routes ⋆ IpCisco, OSPF External Route selection algorithm - Cisco Community

Referring to the exhibit, the service provider should implement L3VPN using the MP-BGP protocol to connect the sites for two customers (indicated in red and green in theexhibit). L3VPN is a type of VPN that uses MPLS to provide IP connectivity between customer sites across a service provider network. L3VPN allows customers to use overlapping or identical IP addresses without causing conflicts or requiring NAT. L3VPN uses MP-BGP to exchange VPN routes between PE routers, which are routers that connect customer networks to the service provider network. MP-BGP is an extension of BGP that can carry multiple address families, such as VPNv4 or VPNv6, along with additional attributes, such as route distinguisher (RD) and route target (RT). RD is used to make customer routes unique within the service provider network, while RT is used to control which routes are imported or exported between different VPNs3 .

References: L3VPN - Layer 3 Virtual Private Networks - Mpirical, [Use of MP-BGP Extensions for IPv6 Interdomain Routing]

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 purpose of the RT attribute is to identify the destination VPN on the egress PE. RT stands for route target, which is a BGP extended community attribute that is used in MPLS VPNs. RT is attached to VPN routes by the ingress PE router and is used to control the import and export of routes between different VPNs. The egress PE router uses the RT value to determine which VPN routes belong to which VPN customers and installs them in the appropriate VRF table56.

References: IP Routing: BGP Configuration Guide - BGP-RT and VPN … - Cisco, : The Ruby Text element - MDN Web Docs

Penultimate hop popping (PHP) is a function performed by certain routers in an MPLS enabled network. It refers to the process whereby the outermost label of an MPLS tagged packet is removed by a label switch router (LSR) before the packet is passed to an adjacent label edge router (LER). The purpose of PHP is to reduce the load on the LER, as it saves one cycle of label lookup. The LER can forward the packet based on its IP header or another label in the stack, without having to process the outer label. PHPfunctionality is achieved by the LER advertising a label with a value of 3 to its neighbors. This label is defined as "implicit-null" and informs the neighboring LSRs to perform PHP12.

References: Penultimate hop popping - Wikipedia, MPLS Penultimate hop popping - NetworkLessons.com

In an Ethernet frame carrying a VLAN tag, the VLAN tag appears before the type field. A VLAN tag is a 4-byte field that is inserted into an Ethernet frame to indicate the VLAN membership and priority of the frame. The VLAN tag consists of two subfields: the tag protocol identifier (TPID) and the tag control information (TCI). The TPID subfield is a 16-bit field that identifies the frame as an IEEE 802.1Q-tagged frame, with a value of 0x8100. The TCI subfield is a 16-bit field that contains the priority code point (PCP), the drop eligible indicator (DEI), and the VLAN identifier (VID). The VLAN tag appears between the source MAC address and the type fields of the original frame, shifting the type field by four bytes. The type field indicates the type of the payload, such as IP or ARP .

References: [IEEE 802.1Q - Wikipedia], [VLAN Tagging Explained with DTP Protocol - GeeksforGeeks]

The function of LSR from an LDP perspective is to distribute labels of FEC to its LDP peers. LSR stands for Label Switching Router, which is a router that forwards packets based on labels rather than IP addresses in an MPLS network. LDP stands for Label Distribution Protocol, which is a protocol that distributes labels for MPLS forwarding along the shortest path calculated by an IGP. FEC stands for Forwarding Equivalence Class, which is a group of packets that are forwarded in the same manner by an LSR. An LSR uses LDP to advertise the label mappings for each FEC to its LDP peers, which are other LSRs that have established an LDP session with it12.

References: Ldp | Microsoft Learn, Label Distribution Protocol - Wikipedia

The maximum number of unique VLAN IDs available is 4096. A VLAN ID is a 12-bit identifier that can range from 0 to 4095. However, VLAN ID 0 is reserved for tagging the priority of frames and VLAN ID 4095 is reserved for implementation use, so only VLAN IDs from 1 to 4094 are available for user configuration78. VLAN IDs are used to identify different broadcast domains or subnets on a Layer 2 network. VLAN IDs are carried in the IEEE 802.1Q tag in the Ethernet frame header.

References: What is a virtual LAN (VLAN) and how does it work with my managed switch? - NETGEAR Support, Virtual LANs (VLANs) - Cisco

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

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

Two protocols that apply to both IPv4 and IPv6 are:

• SNMP: This stands for Simple Network Management Protocol, which is a protocol that allows network administrators to monitor and manage network devices such as routers, switches, servers, printers, etc. SNMP uses a client-server model, where an SNMP manager (client) can query or configure an SNMP agent (server) on a network device using SNMP messages. SNMP can operate over both IPv4 and IPv6 networks56.
• DNS: This stands for Domain Name System, which is a protocol that translates human-readable domain names (such as www.example.com) into numerical IPaddresses (such as 192.0.2.1 or 2001:db8::1) that identify network devices. DNS uses a hierarchical distributed database of name servers that store and resolve domain names and IP addresses. DNS can support both IPv4 and IPv6 addresses78.

References: Simple Network Management Protocol - Wikipedia, SNMP over IPv6 - Cisco, Domain Name System - Wikipedia, DNS for IPv6 - Cisco

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

In the exhibit, router R4 is performing a swap action. This means that router R4 is replacing the incoming label with a new label and forwarding the packet to the next hop along the LSP. In this case, router R4 receives a packet with label 20 from router R3 and swaps it with label 30 before sending it to router R5.

The exhibit shows an example of an MPLS network with four routers: R1, R2, R3, and R4. Router R1 is the ingress PE router and router R4 is the egress PE router. Router R2 and R3 are P routers. Router R1 assigns label 10 to the packet and sends it to router R2. Router R2 swaps label 10 with label 20 and sends it to router R3. Router R3 swaps label 20 with label 30 and sends it to router R4. Router R4 removes label 30 from the packet and forwards it based on its IP header or another label in the stack.

Therefore, the answer is D.

References: MPLS Label Switching | MPLS Operation | Push, Swap,Push ⋆ IPCisco, A Complete Guide to Multiprotocol Label Switching (MPLS) - G2, Multiprotocol Label Switching - Wikipedia

MTU mismatch would cause an IS-IS adjacency between two routers to fail. MTU stands for maximum transmission unit, which is the maximum size of a packet that can be transmitted on a link. IS-IS hellos are padded to the full MTU size, partly to allow a router to implicitly communicate its MTU to its neighbors. If two routers have different MTUs on their interfaces, they will not be able to exchange hellos properly, and their adjacency will not form or will be dropped34. To solve this problem, the MTUs on both interfaces must be configured to match.

SEL, context, and SysID are not fields that would cause an IS-IS adjacency failure. SEL stands for selector, which is a one-octet field that identifies the network layer service to which a packet should be sent. For IS-IS routers, the SEL must always be 005. Context is not a field in IS-IS packets, but rather a term used to describe the scope of routing information in different levels or areas6. SysID stands for system identifier, which is a six-octet field that uniquely identifies a router within an area. SysID does not have to match between two routers for them to form an adjacency7.

References: MTU Mismatch Problem in IS-IS - Cisco, IS-IS adjacency is not formed due to MTU mismatch - Cisco Community, IS-IS NSAP address - Cisco Community, Understanding IS-IS Routing Contexts - Juniper Networks, IS-IS - Nokia

The route type that is restricted in an OSPF stub area is type 5. Type 5 LSAs are external LSAs that are generated by ASBRs to advertise routes from other routing domains or protocols into OSPF. Type 5 LSAs are flooded throughout the OSPF domain by default, except in stub areas. Stub areas are special OSPF areas that block type 5 LSAs from entering the area in order to reduce the size of the LSDB and the routing table. Stub areas only receive information about intra-area routes (type 1 and 2 LSAs), inter-area routes (type 3 LSAs), and a default route (type 3 LSA with destination 0.0.0.0/0) from the ABRs910.

References: Introduction to OSPF Stub Areas - NetworkLessons.com, What Are OSPF Areas and Virtual Links? - Cisco

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

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

The subnet address for 10.57.126.156/29 is 10.57.126.152. To find the subnet address, we need to perform a bitwise AND operation between the IP address and the subnet mask. The subnet mask for /29 is 255.255.255.248, which in binary is 11111111.11111111.11111111.11111000. The IP address in binary is 00001010.00111001.01111110.10011100. The result of the AND operation is 00001010.00111001.01111110.10011000, which in decimal is10.57.126.152. References: Ericsson IP Networking - IP Addressing, Software Installation and Upgrade Overview (Junos OS)