Error Handling Network Layer
one or more networks, while preserving the class of service and error handling tasks. The Network Layer is accountable for source to destination packet deliverance and routing through intermediate networks. On the other hand, the Data Link Layer is in charge of node-to-node frame deliverance on a similar channel. The Network Layer executes network routing tasks and may also carry out fragmentation and reassembly, and report deliverance errors. Routers work at the Network Layer, distributing information throughout the entire network. Network Layer Functions Path Determination/Routing: The Network Layer manages arriving packets from different sources, decides their finishing destination, and then makes a decision regarding where to send the packets to make them reach the final destination. Logical Addressing: Each and every component participating in a network communication has a logical address commonly known as the layer-3 address. Addressing is also carried out at the data link layer, but it refers to local physical components. Logical addresses are not dependent on specific hardware and must be distinct across a complete network. Forwarding: In the process of routing the packets to their final destination, the Network Layer needs to keep forwarding the packets to concerned intermediate nodes. Datagram Encapsulation: The Network Layer encapsulates the various messages received from upper layer into Packets (also known as Datagram) attached with a header. Fragmentation and Reassembly: The Network Layer usually breaks up the packets into smaller messages to be transferred to the Data Link Layer and reconnects them to reform the packet. Error Handling and Diagnostics: The Network Layer also handles various communication errors, routing flaws, and status exchanges. Network Layer Standards Stand
a list of references, but its sources remain unclear because it has insufficient inline citations. Please help to improve this article by introducing more precise citations. (October 2009) (Learn how and when to remove this template message) OSI model by layer 7. Application layer NNTP SIP SSI DNS FTP Gopher HTTP NFS NTP SMPP SMTP SNMP Telnet DHCP Netconf more.... 6. Presentation layer MIME XDR 5. Session layer Named pipe NetBIOS SAP PPTP RTP SOCKS http://www.tech-faq.com/network-layer.html SPDY 4. Transport layer TCP UDP SCTP DCCP SPX 3. Network layer IP IPv4 IPv6 ICMP IPsec IGMP IPX AppleTalk X.25 PLP 2. Data link layer ATM ARP IS-IS SDLC HDLC CSLIP SLIP GFP PLIP IEEE 802.2 LLC MAC L2TP IEEE 802.3 Frame Relay ITU-T G.hn DLL PPP X.25LAPB Q.921 LAPD Q.922 LAPF 1. Physical layer https://en.wikipedia.org/wiki/Network_layer EIA/TIA-232 EIA/TIA-449 ITU-T V-Series I.430 I.431 PDH SONET/SDH PON OTN DSL IEEE 802.3 IEEE 802.11 IEEE 802.15 IEEE 802.16 IEEE 1394 ITU-T G.hn PHY USB Bluetooth RS-232 RS-449 v t e In the seven-layer OSI model of computer networking, the network layer is layer 3. The network layer is responsible for packet forwarding including routing through intermediate routers, since it knows the address of neighboring network nodes, and it also manages quality of service (QoS), and recognizes and forwards local host domain messages to the Transport layer (layer 4).[1] The data link layer (layer 2) is responsible for media access control, flow control and error checking. Contents 1 Functions 2 Protocols 3 Relation to TCP/IP model 4 See also 5 References 6 External links Functions[edit] The network layer provides the functional and procedural means of transferring variable-length data sequences from a source to a destination host via one or more networks, while maintaining the quality of service functions. Functions of the network layer
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to this Thread… Solcism Junior Member Registered Member Join Date Sep 2010 Posts 1 04-03-201206:58 PM #1 Error Checking OSI Model. Question, so layer 2 handles error detection and error correction. But so does layer 4 correct? Can someone elaborate? Quote Login/register to remove this advertisement. SharkDiver Senior Member Join Date Aug 2011 Location N. Carolina Posts 837 Certifications CCNP, CCNA Security, CCNA Voice, CCNA, CCENT, Project+, Security+, Network+, A+, Avaya AIPS and ACSS, ITIL Foundation (2011) 04-03-201210:16 PM #2 I think this is what you are looking for. From Wikipedia: EthernetSince bit errors are very rare in wired networks, Ethernet does not provide flow control or automatic repeat request (ARQ), meaning that incorrect packets are detected but only cancelled, not retransmitted (except in case of collisions detected by the CSMA/CD MAC layer protocol). Instead, retransmissions rely on higher layer protocols. So, Layer 2 will detect the error and cancel it, but Layer 4 TCP will request retransmission when it notices a segment is missing (using sequencing). Quote quinnyfly Senior Member Join Date Mar 2008 Location Brisbane, Australia Posts 235 Certifications A+, Network+, Security+ ce, Server+, CIW - Network Technology Associate, CIW - Web Security Professional 04-04-201212:54 AM #3 Layer 4 is the one that guarantees the reliable delivery of data, error detection and correction take place here. TCP and UDP operate at layer 4, TCP request a packet be resent if it is corrupt (checksum different) or has parts missing. (error detection). It then has the transmittting device resend packets (error correction). Layer 2 on the otherhand is the part that prepares the packets for transmission over the media before it is handed down to the physical l