Ericsson ECP-206 Exam

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 .

Two statements that are true regarding the LSP are:

The LSP refers to a sequence of routers that forward the MPLS packet based on labels. An LSP is a Label Switched Path, which is a path through an MPLS network that is established by signaling protocols such as LDP or RSVP-TE. An LSP consists of a sequence of routers (called Label Switching Routers or LSRs) that forward packets based on labels rather than IP addresses. Labels are short fixed-length identifiers that are attached to packets at the ingress router and removed at the egress router.Labels can be swapped or popped at intermediate routers according to their label forwarding tables78.

The LSP refers to a sequence of routers that add, remove, or change label values along the path. As mentioned above, an LSP consists of a sequence of routers that forward packets based on labels. Along the path, different routers may perform different operations on the labels depending on their role and configuration. The ingress router adds one or more labels to the packet before sending it into the MPLS network. The egress router removes all labels from the packet before sending it out of the MPLS network. The intermediate routers may swap one label with another label according to their label forwarding tables.This process is called label switching78.

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.

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 .

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.