Ipt - Ispit 2. Deo

The correct answer is ECN. ECN stands for Explicit Congestion Notification. It is a flag that is set in the header of a TCP segment to indicate that congestion has occurred in the network. When a router detects congestion, it can set the ECN flag in the TCP header to notify the receiving end. This allows the receiving end to adjust its transmission rate and reduce congestion in the network.

The correct answer is "Servera". The question is asking about the transition from one state to another in a TCP connection. Since the question does not provide any specific context or details, we can assume that the transition being referred to is on the server side. Therefore, the correct answer is "Servera".

Protokoli rutiranja sa stanjem veze grade kompletnu topološku mapu. This means that they create a detailed map of the entire network, including all the routers and their connections. By having this complete map, the routing protocol can make more informed decisions about the best path for routing packets. This allows for more efficient and accurate routing in the network.

Dijkstra algorithm is used for OSPF (Open Shortest Path First). This algorithm is used to find the shortest path between nodes in a graph. In the context of OSPF, it is used to calculate the shortest path between routers in a network, based on the cost associated with each link. The algorithm iteratively selects the node with the lowest cost and updates the cost of its neighboring nodes until the shortest path to all nodes is determined. Therefore, Dijkstra algorithm is the correct answer for the given question.

not-available-via-ai

When the TTL (Time to Live) field of a packet reaches 0, the IP packet is discarded and an ICMP (Internet Control Message Protocol) message is sent to the source. This is done to inform the source that the packet has expired and was not delivered successfully.

not-available-via-ai

The correct answer is A because it accurately describes the three-way handshake procedure for establishing a TCP connection. In this procedure, host A sends a TCP segment with the SYN bit set to initiate the connection. Host B then responds with a TCP segment that has both the SYN and ACK bits set to acknowledge the request and establish a connection. Finally, host A sends a TCP segment with the ACK bit set to confirm the connection establishment. This three-step process ensures that both hosts agree to establish a reliable connection before transmitting data.

Routing using distance vector reacts slowly to bad news. This means that when there is a change in the network, such as a link failure or congestion, distance vector routing algorithms take longer to update their routing tables and adapt to the new conditions. This can result in suboptimal routing decisions and slower convergence compared to other routing algorithms.

An autonomous system is a collection of networks and routers that are under a single administration. This means that the networks and routers within the autonomous system are managed and controlled by the same entity. This allows for efficient management and coordination of the network infrastructure within the autonomous system.

The correct answer is "Identifikator je jednog interfejsa" which translates to "Identifier is one of the interfaces" in English. This answer suggests that a unicast address is used to identify a single interface in a network.

Protokoli za rutiranje služe ruterima da međusobno dele informacije o dostupnim mrežama. Ovi protokoli omogućavaju ruterima da razmenjuju informacije o najboljim putanjama za slanje podataka između različitih mreža. Na taj način, ruteri mogu efikasno usmeravati podatke kroz mrežu i osigurati da stignu na odredište. Protokoli za rutiranje omogućavaju ruterima da održavaju ažurirane tabele rutiranja koje sadrže informacije o dostupnim mrežama i njihovim putanjama.

The given correct answer is "Ad-Hoc routing". Ad-Hoc routing refers to a type of routing protocol where nodes in a network dynamically form a temporary network without the need for any pre-existing infrastructure or centralized administration. In this scenario, node X is missing a path to node Y, so it sends a ROUTE REQUEST packet to its directly connected neighbors. These neighbors can either reply with a ROUTE REPLY or increment the hop count and forward the ROUTE REQUEST to their own neighbors. This process is an example of how ad-hoc routing works.

Dividing routers into regions is a solution to handle the growth of the network. This approach helps in reducing the size of the routing tables by dividing the network into smaller regions, with each region having its own routing table. This way, the routers only need to maintain information about the routes within their respective regions, which helps in improving the efficiency and scalability of the network.

TTL stands for Time to Live. It represents the maximum amount of time or number of hops that a packet can take before it is discarded. Each time the packet passes through a router, the TTL value is decremented by 1. This ensures that if a packet gets stuck in a loop or takes too long to reach its destination, it will eventually be discarded to prevent network congestion. Therefore, the correct answer is "Vreme trajanja paketa, i vrednost se pri svakom prolazu kroz ruter dekrementira za 1" which means "Packet lifetime, and the value is decremented by 1 at each router passage."

The correct answer is "Ni adresa mreže ni adresa stanice ne mogu imati nultu vrednost" which means "Neither the network address nor the host address can have a zero value." This means that in a RIP packet, both the network address and the host address must have a non-zero value.

The correct answer suggests that the growth of the network can be solved by dividing routers into regions. This means that instead of having a single large routing table for the entire network, the routers are divided into smaller regions, each with its own routing table. This helps to reduce the size and complexity of the routing tables, making the network more efficient and scalable. By dividing the routers into regions, the routing process can be simplified and optimized, leading to better network performance.

The correct answer is "Izvorišni host" (Source host). When entering a token, it is the source host that provides the token.

The correct answer is "Parom transportne i mrežne adrese." This means that the address of the application user is uniquely determined by the pair of transport and network addresses. In networking, the transport address refers to the specific port number used by the application, while the network address refers to the IP address of the device. Together, these two addresses uniquely identify the application user.

The correct answer is "Polje koje ukazuje na kraj hitnih podataka" which translates to "Field that indicates the end of emergency data." This suggests that there is a field in a system or data structure that is specifically designated to indicate the end of emergency data.

The given answer, 2001:E:DB8:101:0:1:0:20, could be used as a compressed representation of the IPv6 address 2001:000E:0DB8:0101:0000:0001:0000:0020. The zeros in each segment of the address have been compressed, resulting in a shorter representation.

The correct answer is "Softverski deo mrežnog sloja" which translates to "Software part of the network layer". This is the correct answer because routing algorithms are implemented in software to determine the best path for data packets to travel through a network. The hardware part of the network layer deals with the physical transmission of data, while the application layer and network access layer are not directly involved in routing.

The correct answer is "Mehanizam kontrole toka predajnika" which translates to "Transmitter flow control mechanism" in English. This means that the transmitter has a mechanism to control the flow of data being transmitted.

The correct answer is SYN SENT. In a transport connection, the SYN SENT state refers to the state where a connection request has been sent to the remote host, but a response has not yet been received. Once the response is received and acknowledged, the connection transitions to the ESTABLISHED state. The other states mentioned (FIN WAIT, IDLE, CLOSE) do not directly lead to the ESTABLISHED state.

The correct answer is 536 bajtova because it is stated in the question that the default segment size is 536 bytes.

The simplest way to increase the space for sequence numbers is by increasing the field for sequence numbers in the segment header. This allows for a larger range of sequence numbers to be used, providing more space for tracking and managing the order of packets. Increasing the memory space of the transmitter or receiver or increasing the packet's lifetime does not directly address the issue of expanding the space for sequence numbers.

The correct answer is "Na zaglavlje, podatke i pseudozaglavlje" which means "On the header, data, and pseudoheader" in English. In TCP, the checksum is calculated over the header, data, and a pseudoheader. The pseudoheader includes the source and destination IP addresses, protocol field, and TCP length. By including the pseudoheader in the checksum calculation, TCP can verify the integrity of the entire TCP segment, including the IP addresses and protocol information.

In this scenario, the correct answer is that there is only one pointer for emergency data at the receiver, and when new emergency data arrives, it is overwritten on the previous data. This suggests that the receiver can only handle one set of emergency data at a time, and any new data will replace the previous data. This explanation implies that there is a limited capacity for emergency data handling at the receiver.

When the connection is interrupted, the virtual circuit is also interrupted.

The correct answer is "Uvođenjem TTL". The Time to Live (TTL) field is used in network packets to limit the lifespan or lifetime of the packet. It is decremented by each router the packet passes through, and if it reaches zero, the packet is discarded. This helps prevent packets from circulating indefinitely in the network and avoids congestion. By introducing the TTL field, the problem of incorrect and duplicated numbers in LSP packets can be resolved.

The reason to avoid using link-state protocols is that they require more memory and consume more memory for data processing compared to distance vector protocols.

The correct answer is "Oznake toka, izvorišne i odredišne adrese." This is because the sentence "Tok IPv6 protokola jedinstveno definiše" suggests that the IPv6 protocol uniquely defines something. Among the given options, only "Oznake toka, izvorišne i odredišne adrese" includes all three elements mentioned in the sentence, which are "Oznake toka" (flow labels), "izvorišne adrese" (source addresses), and "odredišne adrese" (destination addresses). Therefore, this option is the correct answer.

The value of the identifier for the "step by step" option in the IPv6 protocol is 0.

For the establishment of a TCP connection, a three-way handshake is required. This involves the exchange of three control segments between the client and the server. The first segment is sent by the client to the server to initiate the connection. The second segment is sent by the server to acknowledge the request and confirm its readiness to establish the connection. Finally, the third segment is sent by the client to acknowledge the server's response and complete the connection setup. This three-step process ensures that both parties are synchronized and ready to communicate.

The given MAC address (08:00:27:a7:9c:eb) is a 48-bit address that uniquely identifies the network interface card (NIC) of the Linux workstation. The IPv6 address (fe80::a00:27ff:fea7:9ceb/64) includes the EUI-64 interface identifier, which is derived from the MAC address. This means that the interface identifier portion of the IPv6 address is generated based on the EUI-64 process, which involves inserting the hexadecimal value "ff:fe" in the middle of the MAC address. Therefore, the correct answer is "Identifikator interfejsa je generisan na osnovu EUI – 64 procesa."

When the connection is in the CLOSE state and receives the ACTIVE OPEN primitive, it sends a SYN segment and transitions to the SYN SENT state.

When creating a subnet, the relevant bits are the ones with the highest weight in the portion assigned to the network address. These bits determine the network ID and are used to identify the subnet. Therefore, the correct answer is that the appropriate number of bits with the highest weight is reserved for the portion assigned to the station's address.

When we talk about protocols, the term "connectionless" means that establishing a connection before data transmission is not mandatory. In connectionless protocols, data packets are sent without the need for a prior connection setup or teardown. This allows for faster and more efficient transmission as there is no need for the overhead of establishing and maintaining a connection.

The correct answer is "Starost zapisa". This suggests that the routing table needs to have a record of the age of the entries. This information is important in determining the freshness or validity of the routing information. By knowing the age of the entries, the router can prioritize the most recent information and make more efficient routing decisions.

The correct answer is "48-bitna eternet MAC adresa i predefinisanih 16 bita". This is because when generating an EUI-64, two parameters are required: a 48-bit Ethernet MAC address and 16 pre-defined bits.

The correct answer is ESTABLISHED because data can only be exchanged when the TCP connection is in the established state. In this state, both the client and the server have successfully completed the three-way handshake process and are ready to transmit data. The active open and passive open states refer to the initial steps of establishing the connection, while the idle state indicates a lack of activity on the connection.

The correct answer is "For a group of interfaces belonging to different nodes." This is because a multicast address is used to identify a group of interfaces that belong to different nodes. Multicast allows for the efficient transmission of data to multiple recipients simultaneously, and the multicast address is used to specify the group of recipients.

The relationship between the transport entity and the user is observed through the primitives and parameters that are exchanged. This means that the transport entity and the user communicate with each other by exchanging specific commands (primitives) and associated information (parameters). These primitives and parameters allow the transport entity to understand the user's requirements and perform the necessary actions to fulfill them.

Each router must have a table with routes to destinations. This table is essential for the router to determine the best path for forwarding packets to their intended destinations. Without this table, the router would not be able to efficiently route network traffic.

The correct answer is "Prvi sledeći bajt koji se očekuje." This means that the confirmation number indicates the first next byte that is expected to be received.

The address field of the IPv6 protocol is 16 bytes long. IPv6 addresses are represented as eight groups of four hexadecimal digits, separated by colons. Each group represents 16 bits, which equals 2 bytes. Therefore, the total length of the address field is 16 bytes.

When the ACK segment is lost, a duplicate can appear on the receiving end. This is because the sender does not receive the acknowledgment of the previously sent packet and assumes that it was lost. As a result, it resends the packet, leading to a duplicate on the receiving end.

The correct answer is "Izračunava se jednostavnim sabiranjem skokova" because the RIP protocol uses a distance-vector algorithm where each router calculates the distance to a destination network by simply adding up the number of hops (or "skokovi") it takes to reach that network. This method is straightforward and does not involve complex calculations or measurements.

This answer is correct because counting to infinity is a characteristic of distance vector routing protocols. In distance vector routing, routers exchange information about the distance and direction to reach different networks. However, these protocols can encounter a problem known as "counting to infinity," where routers keep incrementing the distance to a network indefinitely, leading to routing loops. To solve this problem, distance vector protocols introduce a maximum limit for the path length, which is considered the "largest possible path."

The correct answer is 255.255.255.240. This subnet mask allows for 14 usable addresses per subnet, which is the maximum number of addresses needed for the 10 subnets required. The other subnet masks listed do not provide enough addresses for the required number of subnets.

The correct answer is "Transportna celina servera pasivno čeka na dolazeću vezu." This means that the server's transport unit passively waits for an incoming connection. In a passive open, the server does not actively initiate the connection but waits for a client to establish the connection.

When a segment is too large for the network, the router will split it into smaller segments. In this case, the router will add a new header of 40 bytes to the segment. This new header will provide additional information and instructions for the network to properly handle the segmented data.

The correct answer is "Četvorostruka razmena upravljačkih segmenata" which means "Four-way handshake is required for breaking the TCP connection." In TCP, a four-way handshake is used to terminate a connection. This involves a series of control segments exchanged between the client and server to ensure a reliable closure of the connection. The four steps include the client sending a FIN segment to the server, the server acknowledging the FIN, the server sending its own FIN segment, and the client acknowledging the server's FIN. This ensures that both ends of the connection are properly closed.

When the selective acknowledgment option is used, the sender will resend only the segments that were not successfully received. This means that instead of resending all the segments, the sender will only focus on the ones that were not successfully received by the recipient. This approach helps to optimize the transmission process by reducing unnecessary retransmissions of already received segments.

The correct answer is "Mrežnu adresu odredišne stanice" (Network address of the destination station). The routing table is used by routers to determine the next hop for forwarding packets. In order to correctly route packets, the router needs to know the network address of the destination station. The MAC addresses are used at the data link layer for communication within a local network, but the routing table is concerned with network addresses. Therefore, the network address of the destination station is the relevant entry for the routing table.

The correct answer is "Protokol koji se koristi u manjim mrežama." This is because the term "Rip protokol" refers to the Routing Information Protocol, which is commonly used in smaller networks. RIP is a distance-vector routing protocol that uses hop count as a metric to determine the best path for data packets in a network. It is typically used in smaller networks where simplicity and ease of configuration are more important than scalability and efficiency.

The correct answer suggests that the routing protocol based on metrics determines the best path to a network. Routing protocols use various metrics, such as hop count, bandwidth, delay, or cost, to calculate the optimal path for data packets to reach their destination. By analyzing these metrics, the routing protocol can determine the most efficient and reliable path for data transmission.

The correct answer is "Protokoli za rutiranje između dva velika posrednika Internet usluga." This answer suggests that the example of an external routing protocol would be protocols used between two large Internet service providers. These protocols would help in routing traffic between these providers and ensuring efficient communication between their networks.

The given answer is "FIN WAIT". This is because the FIN WAIT state is one of the possible states from which a transport unit can transition to the CLOSED state. The other states listed (ESTABLISHED, SYN SENT, and ACTIVE OPEN) are not mentioned as possible transitions to the CLOSED state.

The correct answer is 58. In IPv6, the next header field is used to identify the protocol of the next header that follows the IPv6 header. The value 58 indicates that the next header is the ICMPv6 protocol.

The number 45 in the "sledeće zaglavlje" field indicates that the next header is a subdomain routing protocol.

By increasing the space for sequence numbers, the chances of duplicate packets occurring will be reduced. This is because each packet is assigned a unique sequence number, and by increasing the space available for these numbers, the likelihood of two packets having the same number decreases. Therefore, increasing the space for sequence numbers is the simplest method to protect against duplicate packets.

The state "TIME - WAIT" is marked as the 2MLS (Two-MSL) wait state. This state occurs when a connection is closed and the system is waiting for a period of time equal to twice the Maximum Segment Lifetime (MSL) before fully closing the connection. During this time, any delayed or out-of-order packets can still be received and processed.

The correct answer suggests that the routing device will package the received frame into a new frame without changing the network layer addresses. This means that the routing device will maintain all the data from the incoming frame's header but will not modify the network layer addresses.

The correct answer is "U zaglavlju SYN segmenta" because the ISN (Initial Sequence Number) is a value used in TCP (Transmission Control Protocol) to initiate a connection between two devices. It is a randomly generated number that is included in the SYN (synchronize) segment header. The ISN helps to ensure the reliability and security of the TCP connection by preventing certain types of attacks, such as sequence number prediction attacks. Therefore, the ISN is found in the header of the SYN segment.

The correct answer is "Jedan kraj veze zatvorio (normalno ili naglo) vezu bez obaveštenja druge strane o tome." This means that one end of the connection closed the connection without informing the other end. This can happen when one end abruptly terminates the connection without sending a proper closing signal to the other end.

The correct answer is "Odnosi na protokole sa vektorom udaljenosti. Ruter ne zna da li se nalazi na putanji koju sused ima ka destinaciji. Rešava se podešavanjem najveće moguće metrike." This explanation states that counting to infinity refers to distance vector protocols, where a router is unaware if it is on the path that its neighbor has towards the destination. This issue is resolved by setting the maximum metric possible.

TCP protokol obezbeđuje kontrolu toka sa primenom mehanizma klizajućeg prozora, što znači da dozvoljava pošiljaocu da pošalje grupu segmenata i da očekuje potvrdu za poslatu grupu segmenata. Ovaj mehanizam omogućava efikasniju komunikaciju između pošiljaoca i primaoca tako što omogućava slanje više segmenata pre nego što se primi potvrda za prethodno poslate segmente. Na taj način se povećava propusnost mreže i smanjuje latencija u komunikaciji.

The correct answer is "To provide a minimum time between closing one connection and opening another connection with the same destination address." This means that the time between closing a connection and opening a new one with the same destination address should be kept to a minimum. This is important to ensure efficient and timely communication between devices.

The correct answer is "Časovnik za retransmisiju" which translates to "Timer for retransmission" in English. This timer is used when the transmitter does not receive a confirmation of successful data segment reception within a certain time. It is responsible for triggering the retransmission of the data segment to ensure reliable communication.

The problem is that host B does not have a default gateway configured. Without a default gateway, host B does not know where to send the packets when trying to communicate with host A.

The correct answer is that each interface of the router has two IPv6 addresses, a local and a global one. This means that for each interface, there are two directly connected networks, resulting in a total of four additional directly connected networks for the router.

Based on the given information, the network prefix is 2001:DB8:1:1::/64 and the hardware address of the Ethernet interface is FC:99:47:75:CE:E0. Since SLAAC (Stateless Address Autoconfiguration) is being used, the host will use the EUI-64 process to configure its global address. The EUI-64 process involves inserting the hexadecimal value "FF:FE" in the middle of the MAC address. Therefore, the host will use the global address 2001:DB8:1:1:FE99:47FF:FE75:CEE0/64.

The correct answer suggests that the rule of divided horizons is based on not sending information learned from one source back to that source. This means that information obtained from a particular source is not shared or communicated back to that same source. This approach ensures that the information remains independent and unbiased, allowing for a more comprehensive and diverse understanding of the subject matter.

The correct answer states that the Ethernet network will be represented as 1 new artificial node. This means that instead of treating each router (X, Y, and Z) as independent nodes, they will be combined into a single node. This representation simplifies the network topology and allows for more efficient routing decisions.

This answer is correct because it states that the description of the routing protocol includes sending updates only when the topology changes, periodic updates occurring less frequently, the ability to classify networks into hierarchical areas, support for classless addressing, and support for summarization. These characteristics are all associated with routing protocols that use link-state information, such as OSPF (Open Shortest Path First) or IS-IS (Intermediate System to Intermediate System).

In the protocol for distance vector routing, routers exchange routing information only with their neighbors. This means that routers share information about the routes they know with the routers that are directly connected to them. By exchanging information with their neighbors, routers can update their routing tables and make better decisions on how to forward packets. This approach helps in reducing the amount of information that needs to be exchanged and processed, making the routing process more efficient.

Multiplexing at the transport layer is used when multiple transport connections use a single virtual network connection. This means that multiple transport connections can share the same virtual network connection, allowing for more efficient use of network resources.

The TCP segment has a header of 20 bytes. The header of a TCP segment contains important information such as source and destination port numbers, sequence and acknowledgment numbers, and various control flags. This header is necessary for the proper functioning of the TCP protocol, as it allows the receiving end to correctly interpret and process the data being transmitted. Having a header size of 20 bytes ensures that this essential information is included while keeping the overall size of the segment manageable.

The given correct answer states that IPv6 packets with the same flow label represent a series of packets that have the same attributes and need to be processed in the same way. This means that these packets share common characteristics, such as the source and destination IP addresses, transport protocol, and other header fields, and should be treated uniformly during processing. The flow label in IPv6 is used to identify packets belonging to the same flow and can be used by network devices to apply specific processing or forwarding rules.

The correct answer is 32 bita because the question is asking about the size of the field for the serial number (SN). In computer systems, a bit is the basic unit of information, and a 32-bit field can store 2^32 different values. Therefore, the serial number field is capable of accommodating a large number of unique values, making it suitable for various applications that require unique identification.

The given IPv6 address (fe80::225:22ff:fe7c:e729) is a link-local address, which is automatically generated for communication within the local network segment. This type of address is assigned to the interface based on the hardware address (adapter's MAC address) and is used for communication with other devices on the same network segment. It is not a globally routable address and is only valid within the local network.

The correct answer is "Statički algoritam." A static algorithm refers to an algorithm that does not change or adapt its behavior based on the input or any other factors. It follows a predetermined set of instructions and does not consider any dynamic changes in the system. In the context of the given options, the static algorithm is the only one mentioned, making it the correct answer.

The correct answer is "Ruter zna detalje o rutiranju paketa unutar lokalne regije, dok su druge regije predstavljene samo jednim zapisom." This means that the router has knowledge about routing packets within its local region, but it only has a single record or representation of other regions. It suggests that the router is aware of the details of routing packets within its own region, but it may not have as much detailed information about other regions.

The correct answer is "PASSIVE OPEN". In the given context, the server is executing a primitive operation at the beginning. Among the options provided, "PASSIVE OPEN" is the most suitable explanation for this operation. This term refers to the process where a server waits for a connection request from a client. It indicates that the server is in a passive state and is ready to accept incoming connections.

The correct answer is that the domestic agent of station X intercepts the packet, finds the location of station X, and tunnels the packet to it. This means that when station Y sends a packet to station X, the domestic agent of station X intercepts the packet and redirects it to the correct location of station X.

The correct answer is "Ponovo se šalju samo neispravni paketi" and "Ponovo se šalju svi paketi od neispravnog pa do onih koji su poslati do prijema negativne potvrde". This means that only the faulty packets are resent and all packets from the faulty one until the receipt of the negative acknowledgment are resent.

Multiplexing down at the transport layer is used when one transport connection uses multiple connections at the network layer. This means that a single transport connection can utilize multiple network connections to transmit data.

The correct answer states that all segments with sequence numbers within the receiving window are accepted. This means that only segments that fall within the range of acceptable sequence numbers will be accepted for further processing.

IPv6 addresses are represented by 128 bits, which is four times the length of IPv4 addresses. Each hexadecimal digit represents 4 bits, so to represent 128 bits, we need 32 hexadecimal digits. Therefore, an IPv6 address consists of 32 hexadecimal digits.

The opening of a window is a field of size 16 bits.

The correct answer is "Vreme koje protekne od trenutka započinjanja slanja segmenta do prijema potvrde za taj segment". This is the definition of Round Trip Time (RTT), which measures the time it takes for a packet to be sent from the source to the destination and for the acknowledgement to be received back at the source. It represents the total time taken for a round trip communication between the sender and receiver.

TCP protokol dozvoljava istovremeno zatvaranje veze. Ovo znači da oba krajnja čvora mogu istovremeno poslati zahtev za zatvaranje veze i prekinuti komunikaciju. TCP će osigurati da se svi preostali podaci prenesu pre nego što se veza potpuno zatvori. Ovo omogućava efikasan i brz prekid veze između dve tačke.

The explanation for the given correct answer is that in a subnet without network establishment, the routing decision is made for each incoming packet individually. This means that each packet is evaluated and routed based on its own characteristics and destination, without considering any previous or future packets. This approach allows for more flexibility and adaptability in routing decisions, as each packet can be treated independently.

The IPv6 address "2001:1234:5678::1" belongs to the global unicast address range. This range is used for unique addresses that are globally routable on the internet. The other options, "FEC0:0DB8::10", "FE80::1", and "FC00:1234:FE", do not fall within the global unicast address range and are used for other purposes such as link-local addresses or unique local addresses.