ECP-206 Ericsson Certified Associate - IP Networking Questions and Answers

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 ambiguity 3 4 .

References :  IPv6 Address Types, Notation, and Structure Explained ,  IPv6 address - Wikipedia

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

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 ASBR 3 4 .

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

According to RFC1918, there are three network blocks reserved as private networks that are not allocated to any specific organization and are not routable on the public Internet. These are:

10.0.0.0/8 (10.0.0.0 - 10.255.255.255)

172.16.0.0/12 (172.16.0.0 - 172.31.255.255)

192.168.0.0/16 (192.168.0.0 - 192.168.255.255)

Out of these, only option B (10.254.1.0/24) falls within one of the private network blocks (10.0.0.0/8). Option A (172.16.1.0/9) is not valid because it exceeds the /12 prefix length of the private network block (172.16.0.0/12). Option C (193.168.1.0/24) is not valid because it does not belong to any of the private network blocks, and is actually assigned to RIPE NCC as a public network block . Option D (172.15.1.0/24) is also not valid because it does not belong to any of the private network blocks, and is actually assigned to ARIN as a public network block .  References :  RFC 1918: Address Allocation for Private Internets ,  Private network - Wikipedia , [RIPE NCC IPv4 Address Space Chart], [ARIN WHOIS Database Search]

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

Two statements that are true about the Ericsson Router 6000 series are:

The Router 6000 uses the same building practice and accessories as the Ericsson Radio System. The Ericsson Radio System is a modular and scalable radio access network solution that supports multiple standards, bands, and layers. The Router 6000 series is fully integrated into the Ericsson Radio System, using the same building practice and accessories such as mounting kits, cables, power supplies, etc.  This simplifies installation, operation, and maintenance of both radio and transport equipment 7 8 .

The Router 6000 products range from all-outdoor small site routers to large aggregation routers. The Router 6000 series consists of three main products: the Router 6672 for access, the Router 6675 for pre-aggregation, and the Router 6274 for metro aggregation. The Router 6672 is an all-outdoor small cell site router with high-capacity and low-power consumption. The Router 6675 is a combined access and E-RAN switch with hardware-accelerated IPSec and high-accuracy internal clock.  The Router 6274 is a high-capacity metro aggregation router with SDN functionality and flexible interface options 7 8 .

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

 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 management 7 8 .

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

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]

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 646 3 4 .

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 646 3 4 .

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

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 is 10.57.126.152.  References :  Ericsson IP Networking - IP Addressing ,  Software Installation and Upgrade Overview (Junos OS)

A label-edged router (LER) is a PE router. A PE router is a provider edge router, which is a router that connects an MPLS network to a customer network. A LER is a term used in MPLS to describe a router that resides at the ingress and egress points of an MPLS network, handling both labelled and unlabelled packets.  A LER performs label operations such as adding, removing, or swapping labels on packets entering or leaving the MPLS network 3 4 .

References :  What is Label Edge Router (LER)? - Definition from Techopedia ,  LER - Label Edge Router - Mpirical

 IPv6 link-local addresses are designed to be used in three situations: for neighbor discovery, for local IP communication on the IPv6 capable routers, and for addressing on a single link for purposes such as auto-address configuration. Neighbor discovery is a protocol that allows IPv6 nodes to discover each other and learn their link-layer addresses on a local network.  Neighbor discovery uses link-local addresses to send and receive messages such as router advertisements, router solicitations, neighbor advertisements, and neighbor solicitations 3 4 . Local IP communication on the IPv6 capable routers refers to the ability of routers to exchange routing information or management traffic using their link-local addresses as source and destination addresses.  This reduces the need for global unicast addresses on router interfaces that are not reachable from outside the local network 3 5 . Addressing on a single link for purposes such as auto-address configuration refers to the use of link-local addresses to enable IPv6 nodes to obtain an address without manual configuration or a DHCP server. Link-local addresses can be automatically derived from the interface identifier in the modified EUI-64 format or randomly generated.  Link-local addresses can also be used to test the connectivity of a link before obtaining a global unicast address 3 6 .

References :  Understand the IPv6 Link-Local Address - Cisco ,  Link Local Address - GeeksforGeeks ,  IPv6 Address Types | Link-Local, Global Unicast, etc.⋆ IPCisco ,  MPLS Label Distribution Protocol Commands - Cisco

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 best routes 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 address 1 2 .

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

OSPF runs directly on IP, while IS-IS runs directly on Ethernet. This means that OSPF uses IP addresses to identify routers and links, while IS-IS uses MAC addresses or other link-layer identifiers. OSPF also requires an IP header for each packet, while IS-IS does not. Both OSPF and IS-IS are link state protocols, which means that they flood information about the network topology to all routers in the same area or domain.  References :  Ericsson IP Networking - Routing Protocols ,  Ericsson Router 6000 Series - Ericsson

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 used 5 6 .

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