Network layer is the third layer (from bottom) in the OSI Model.<\/p>\n
Responsibilities of Network Layer:<\/strong><\/p>\n There are two types of network transmission techniques, circuit switched network and packet switched network.<\/p>\n[ad type=”banner”]\n Circuit Switch vs Packet Switch<\/strong> In a circuit switched network, the data packets are received in order whereas in a packet switched network, the data packets may be received out of order.<\/p>\n IPv4:<\/strong> IPv4 Datagram Header<\/strong> Network Layer | Introduction and IPv4 Datagram Header – Network Layer – Network layer is the third layer (from bottom) in the OSI Model<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[82277,71771],"tags":[82878,82871,82877,82874,82875,82872,82873,82876],"class_list":["post-28384","post","type-post","status-publish","format-standard","hentry","category-computer-networks","category-cs-subjects","tag-ethernet-header","tag-ipv4-header-format-explanation","tag-ipv4-header-format-pdf","tag-ipv4-pdf","tag-ipv6-datagram-format","tag-ipv6-header","tag-tcp-header-format","tag-udp-header-format"],"_links":{"self":[{"href":"https:\/\/www.wikitechy.com\/technology\/wp-json\/wp\/v2\/posts\/28384","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.wikitechy.com\/technology\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.wikitechy.com\/technology\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.wikitechy.com\/technology\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.wikitechy.com\/technology\/wp-json\/wp\/v2\/comments?post=28384"}],"version-history":[{"count":0,"href":"https:\/\/www.wikitechy.com\/technology\/wp-json\/wp\/v2\/posts\/28384\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.wikitechy.com\/technology\/wp-json\/wp\/v2\/media?parent=28384"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.wikitechy.com\/technology\/wp-json\/wp\/v2\/categories?post=28384"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.wikitechy.com\/technology\/wp-json\/wp\/v2\/tags?post=28384"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}Packet forwarding\/Routing of packets:<\/strong> Relaying of data packets from one network segment\r\n to another by nodes in a computer network\r\n\r\nConnectionless communication(IP):<\/strong> A data transmission method used in packet switched \r\n networks in which each data unit is separately \r\n addressed and routed based on information carried \r\n by it\r\n\r\nFragmentation of data packets:<\/strong> Splitting of data packets that are too large to be\r\n transmitted on the network<\/pre>\n
\nIn circuit switched network, a single path is designated for transmission of all the data packets. Whereas, in case of a packet switched network, each packet may be sent through a different path to reach the destination.<\/p>\n
\nIPv4 is a connectionless protocol used for packet switched networks. It operates on best effort delivery model, in which neither delivery is guaranteed, nor proper sequencing or avoidance of duplicate delivery is assured.
\nIPv4 uses 32-bit (4 byte) addressing, which gives 232<\/sup> addresses. IPv4 addresses are written in the dot decimal notation, which comprises of four octets of the address expressed individually in decimal and separated by periods, for instance, 192.168.1.5.<\/p>\n[ad type=”banner”]\n
\nSize of the header is 20 to 60 bytes.<\/p>\nVER:<\/strong><\/em> Version of the IP protocol (4 bits), which is 4 for IPv4\r\n\r\nHLEN:<\/strong><\/em> IP header length (4 bits), which is the number of 32 bit \r\n words in the header. Minimum value for this field is 5\r\n and the maximum is 15\r\n\r\nType of service:<\/strong> <\/em>Low Delay, High Throughput, Reliability (8 bits)\r\n\r\nTotal Length:<\/strong> <\/em> Length of header + Data (16 bits), which has a \r\n minimum value 20 bytes and maximum is 65,535 bytes\r\n\r\nIdentification:<\/strong><\/em> Unique Packet Id for identifying the group of \r\n fragments of a single IP datagram (16 bits)\r\n\r\nFlags:<\/strong><\/em> 3 flags of 1 bit each : reserved bit (must be zero),\r\n do not fragment flag, more fragments flag (same order)\r\n\r\nFragment Offset:<\/strong><\/em> Specified in terms of number of 8 bytes, which has \r\n the maximum value of 65,528 bytes\r\n\r\nTime to live:<\/strong><\/em> Datagram\u2019s lifetime (8 bits), It prevents the datagram \r\n to loop in the network\r\n\r\nProtocol:<\/strong> <\/em> Name of the protocol to which the data is to be passed \r\n (8 bits)\r\n\r\nHeader Checksum:<\/strong><\/em> 16 bits header checksum for checking errors in the \r\n datagram header\r\n\r\nSource IP address:<\/strong><\/em> 32 bits IP address of the sender\r\n\r\nDestination IP address:<\/strong><\/em> 32 bits IP address of the receiver\r\n\r\nOption:<\/strong><\/em> Optional information such as source route<\/pre>\n[ad type=”banner”]\n","protected":false},"excerpt":{"rendered":"