Important Ericsson ECP-206 Exam Questions

Answer: A, C

Explanation:

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 IP addresses (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.

Answer: C

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.Reference:Ericsson IP Networking - Routing Protocols,Configure Attach Bit Set - Cisco

Answer: D

Explanation:

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.

Answer: C

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.

Answer: A, B

Explanation:

Route summarization is a technique that reduces the number of routes that a router advertises to its neighbors by creating a single summary route that covers multiple subnets or networks. Route summarization has several benefits, such as:

It reduces the size of a routing table, which saves memory and CPU resources on the router. A smaller routing table also improves the lookup efficiency and convergence time of the routing protocol.

It reduces signaling, which means that less bandwidth is consumed by routing updates and less processing is required by neighboring routers. This also enhances the stability and scalability of the network, as fewer routing changes are propagated.

It improves route aggregation, which means that more specific routes are replaced by a less specific route that can be advertised to other autonomous systems or routing domains. This simplifies the inter-domain routing and hides the internal topology details.

Route summarization does not necessarily summarize the routing table entries into a default route, although a default route can be considered a special case of route summarization where all destinations are covered by one route. Route summarization also does not improve the best route calculation, as it may introduce suboptimal routing or black holes if not done properly.Reference:Introduction to Route Summarization - NetworkLessons.com,Route Summarization > Example for Understanding Route Summarization - Cisco Press