Question

1. Which of the following in connectionless – Ethernet, IP, TCP? Explain why.
2. Which of the following is unreliable – Ethernet, IP, TCP, UDP? Explain why.
3. Why is it a good idea to have reliability at the transport layer?
4. How many layers of the hybrid TCP-IP stack does a typical
5. 1. Router implement?
   2. Switch implement?
   3. Destination host implement?

Answer 1

A) IP is a connectionless
Description:

• Internet protocol is connectionless in this all packets in science network area unit routed severally, they will not essentially bear a similar route, whereas during a virtual circuit network that is connection-oriented, all packets bear a similar route. This single route is what 'virtual circuit' suggests that.
• With affiliation, as a result of there is only one route, all information packets can arrive within the same order as they're sent out.
• Without affiliation, it's not secure all information packets can arrive within the same order as they're sent out.

B) UDP could be a connectionless, unreliable protocol that has no carry algorithms in it.

C) The transport layer is additionally chargeable for managing the dependability necessities of speech communication. different|completely different} applications have different transport dependability necessities.

IP cares solely with the structure, addressing, and routing of packets. information processing doesn't specify however the delivery or transportation of the packets takes place. Transport protocols specify the way to transfer messages between hosts. TCP/IP provides two transport layer protocols, Transmission Management Protocol (TCP) and User Datagram Protocol (UDP), as shown within the figure. information processing uses these transport protocols to change hosts to speak and transfer knowledge.

TCP is thought-about a reliable, full-featured transport layer protocol, that ensures that every one of the info arrives at the destination. In distinction, UDP is an awfully straightforward transport layer protocol that doesn't offer any dependability.

d)Hybrid model:
In the universe, we have a tendency to use a mixture of each OSI model and also the TCP/IP model, referred to as the Hybrid model. within the Hybrid model, the applying layer could be a combination of layer seven, layer 6 and layer five of the OSI model (similar to the TCP/IP model). The remaining layers (layer 1, 2, 3 and 4) area unit a similar because of the OSI model.

1)Application

2)Transport

3)Network

4)Datalink

5)Physical



a) ROUTER IMPLEMENTATION:

Routers perform the traffic directive functions on the Internet. knowledge sent through the web, like a web page or email, is within the kind of knowledge packets. A packet is typically forwarded from one router to a different router through the networks that represent an internetwork (e.g. the Internet) till it reaches its destination node.

A router has 2 kinds of network part parts organized onto separate processing planes:

Control plane: A router maintains a routing table that lists that route ought to be accustomed forward a knowledge packet, and through that physical interface association. It will this victimization internal pre-configured directives, called static routes, or by learning routes dynamically using a routing protocol. Static and dynamic routes area unit keep within the routing table.
Forwarding plane: The router forwards knowledge packets between incoming and outgoing interface connections. It forwards them to the right network sort victimization info that the packet header contains matched to entries within the FIB equipped by the management plane.

b) SWITCH IMPLEMENTATION:

A switch, within the context of networking, could be a high-speed device that receives incoming knowledge packets and redirects them to their destination on space|a neighborhood} area network (LAN). A local area network switch operates at the info link layer (Layer 2) or the network layer of the OSI Model and, as such, it will support every kind of packet protocols. basically, switches area unit the traffic cops of a straightforward native space network.

Implementation:
Software Switch:
software switch designed employing an all-purpose processor with four network interface cards (NICs). the trail for a typical packet that arrives on, say, NIC one and is forwarded out on NIC a pair of is easy. Once the packet is in memory, the central processor examines its header to see that interface the packet ought to be sent out on, and instructs NIC a pair of to transmit the packet, once more directly out of main memory victimization DMA.

Hardware Switch:
Hardware switch style is that a given white-box will be programmed to be associate L2 switch, and L3 router, or a mix of each, simply by a matter of programming. the precise same management plane computer code stack utilized in a computer code switch still runs on the management central processor, however additionally, knowledge plane "programs" area unit loaded onto the NPU to mirror the forwarding selections created by the management plane computer code. specifically however one "programs" the NPU depends on the chip merchandiser, of that there area unit presently many.

C) IMPLEMENTATION OF HOST SERVICE:

Almost all application-level protocols use unicast for communication. Some examples are as follows: File Transfer Protocol (FTP), Hyper-Text Transfer Protocol (HTTP), and Simple Mail Transfer Protocol (SMTP). as an example, once an e-mail server sends mail to a different server, the steps performed ar almost like these:

1.A Domain Name System (DNS) server is queried, to inform UN agency is chargeable for mail (MX—mail exchanger) for the domain somewhere.com is.

2. The information processing address for the hostname obtained on step one is obtained from the DNS server.

3. A unicast affiliation is established with the magnetic flux unit host at somewhere.com.

4. The causation server identifies the domain from that the message originates.

5. The causation server identifies the e-mail of the message sender.

6. The causation server identifies the e-mail of the message recipient.

7. The e-mail knowledge is shipped.

These are the steps to follow to implement the host service.

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