can you explain the application layer of a tcp/ip and its functions?
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The application layer of TCP/IP is the layer where applications gain access. There are many standards TCP/IP utilities and services at the Applications layer such as FTP, Telnet, SNMP and DNS. \nMicrosoft TCP/IP provides two interfaces for network applications. Windows sockets-standard application programming interface (API) under Microsoft Windows for transport protocols such as TCP/IP and IPX.
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This is a feature that is mostly used in corporate environment to implement proxy functionality.  One port is connected to the outside world and the other is connected to the internal network, the computer can also be plugged into two independent sub-network
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Its a set of rules.Like u hav the IP protocol that specifies the format in the internet layer
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Any IP sender can blast data faster than the recipient or the network can handle.  This can lead to an endless cycle of retransmissions.  TCP uses congestion control to dynamically adjust the sliding window of the sender to adapt to the perceived available bandwidth between the sender and receiver. \n\nMore detail: http://www.borella.net/mike/MITP432/09%20tcp.pdf
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Networking Tools\n\n    * Ping.exe : The BIG one. This is probably one of the most used tools for TCP/IP. Ping sends ICMP Echo Requests to verify that TCP/IP is configured correctly and that a remote TCP/IP system is available. Ping is very customizable through switches. This should be your first stop during times of networking problems. Using it to test network response time is but one of it's many functions.\n    * Arp.exe : allows you to view and modify the ARP (Address Resolution Protocol) cache on the interface of the local computer to detect invalid entries.\n    * Nslookup.exe : Check records, domain host aliases, domain host services, and operating system information by querying Internet domain name servers. When you start Nslookup, it shows the host name and IP address of the DNS server that is configured for the local system, and then display a command prompt for further queries. If you type a question mark (?), Nslookup shows all available commands. You can exit the program by typing exit. To look up a host's IP address using DNS, type the host name and press Enter. Nslookup defaults to using the DNS server configured for the computer on which it is running, but you can focus it on a different DNS server by typing server (where is the host name of the server you want to use for future lookups). Once another server is specified, anything entered after that point is interpreted as a host name.\n    * Hostname.exe : Displays the hostname of the computer.\n    * Ipconfig.exe : Displays current TCP/IP network configuration values. You can update or release DHCP (Dynamic Host Configuration Protocol) allocated leases, and display register, or flush DNS (Domain Name System) names. Output can be redirected to a file if desired.\n    * Nbtstat.exe : Check the state of current Netbios over TCP/IP connections, update the NETBIOS name cache, and determine the registered names and scope ID. Nbtstat is designed to help troubleshoot NetBIOS name resolution problems. When a network is working ok, NetBIOS over TCP/IP (NetBT) resolves NetBIOS names to IP addresses. It does this through several options for NetBIOS name resolution, including local cache lookup, WINS server query, broadcast, LMHOSTS lookup, Hosts lookup, and DNS server query.\n    * Netstat.exe : Displays protocol statistics and current TCP/IP connections. Very cool utility. Try running it while connected to the net.\n    * Pathping.exe : Trace a path to a remote system and report packet losses at each router along the way. Pathping combines features of Tracert and ping.\n    * Route.exe : Display the IP routing table, and add or delete IP routes.\n    * Tracert: Trace a path to a remote system. This tool gives you the number of hops a packet must make to get there, and the IP address of each hop. It does this for a maximum of 30 hops. This tool is very useful for seeing where a problem with a slow response time may lie.\n    * NetDiag.exe : a diagnostic tool that helps isolate networking and connectivity problems by performing a series of tests to determine the state your network client and whether it is functional. Using the /l switch will output results to netdiag.log as the results can be lengthy. This tool will likely not be installed on your system by default. What you must do is go into your Windows 2000 CD in the support/tools directory. Run the setup file there for full access to the Windows 2000 Support Tools. I had problems with getting this program running due to fatal errors from it, but see how you make out. I'll keeps troubleshooting it to see what I can do. \n\nNon Networking Tools\n\n            /? switch displays options on these utilities as well.\n\n    * Sfc.exe : System File Checker. This utility scans protected system files and replaces files overwritten with the correct system files provided by Microsoft. This could prove to be an invaluable tool for repairing your system after some of those search and replace programs that we all know
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Hmmm.  Not really understanding your question, but I'll take a stab at it...  Yahoo mail works via a web browser, which is an application.  The Application Layer is Layer 7 in the OSI Model.  The OSI, or Open System Interconnection, model defines a networking framework for implementing protocols in seven layers. Control is passed down from one layer to the next, starting at the application layer in one station, proceeding to the bottom layer, over the channel to the next station and back up the hierarchy to layer 7 on the destination computer. \n\nLayer 7 supports application and end-user processes. Communication partners are identified, quality of service is identified, user authentication and privacy are considered, and any constraints on data syntax are identified. Everything at this layer is application-specific. This layer provides application services for file transfers, e-mail, and other network software services. Telnet and FTP are applications that exist entirely in the application level. Tiered application architectures are part of this layer.
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Well, the classic Internet reference book is, of course, "Internetworking With TCP/IP" by Douglas Comer. Unless you're doing low-level programming, i.e. writing the code that shoves data packets around, it isn't the book for you.\n\nThere are plenty of Firefox books around if you want a user-level guide:\n\nhttp://www.oreilly.com/catalog/bluee/index.html\nhttp://www.oreilly.com/catalog/0975240242/index.html\nhttp://www.oreilly.com/catalog/firefoxhks/index.html
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The same way you transfer any kind of UDP packets; dial-up makes no difference.  Usually users are not concerned with the underlying transport mechanisms, TCP or UDP.  UDP packets may be transferred programatically using standard methods.\n\nWhat are you trying to accomplish?
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The 'traceroute' program/utility uses the IP header  field called 'TTL' (or Time To Live) to illustrate the route a packet takes across a network en route to a given destination. As a packets traverses each hop along a route, the TTL value is decrimented until the packet reaches its destination. The traceroute program also measures latency to each hop along that route.\n\nThe program typically sends 3 UDP (in some versions it's ICMP) packets with an initial TTL value of 0 to a destination. However, when the packets hit the gateway node, that machine notes the TTL value is '0' and knows to return the packet back to the source. The program notes where the packet then came from and the elapsed time (latency). Again, the program sends another set of packets, this time with a TTL of 1. The gateway node receives the packet, decriments the TTL and forwards it to the next hop along the route. At hop #2, the packet now has a TTL of 0. The traceroute program increments the TTL value each iterration until the packet reaches the destination noce. Once reached, the output shows all the nodes along the route and the latency to each.\n\nIt's important to note that most Internet connections traverse asymmetric routes. That's to say that the route the packet took from the source to the destination is not necessarilly the route the packet will take on the way back. Tracroute only shows you the route in one direction. The only true way to get an idea of the path a packet takes between nodes A and B on the Internet is to view traceroute output from A to B as well as from B to A.
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One can only functionally position the internet model to the ISO OSI model because basic differences exist such as: \n\nIn the internet protocol suite, a layer represents a reasonable packaging of function. \nThe ISO view, on the other hand, treats layers as rather narrow functional groups, attempting to force modularity by requiring additional layers for additional functions. \n\nIn the TCP/IP protocols, a given protocol can be used by other protocols within the same layer, whereas in the OSI model two separate layers would be defined in such circumstances. Examples of such "horizontal dependencies" are FTP, which uses the same common representation as TELNET on the "application layer," and ICMP, which uses IP for sending its datagrams on the "internetwork" layer. \n\nIn practice, what we are discussing here is the difference between a de jure standard, OSI, and a de facto standard, TCP/IP. The focus in the TCP/IP world is on agreeing on a protocol standard which can be made to work in diverse heterogeneous networks. The focus in the OSI world has always been more on the standard than the implementation of the standard. \n\nEfficiency and feasibility. The OSI norms tend to be prescriptive (for instance the "layer N" must go through "all layers below it"), whereas the TCP/IP protocols are descriptive, and leave a maximum of freedom for the implementers. One of the advantages of the TCP/IP approach is that each particular implementation can use operating system-dependent features, generally resulting in a greater efficiency (fewer CPU cycles, more throughput for similar functions), while still ensuring "interoperability" with other implementations. \nAnother way to see this is that most of the internet protocols have first been developed (coded and tested), before being "described" in an RFC (usually by the implementer) which clearly shows the feasibility of the protocols. \n\n2.14.2 The Internet World and OSI \nThe Department of Defense (DoD), funder of the original ARPANET research, made a statement on OSI in January '88, based on the Government OSI Profile (GOSIP) of April 22, 1987. \n\nThe following is an excerpt from the statement, which is published in RFC 1039 - A DoD Statement on OSI: "... It is intended to adopt the OSI protocols as a full co-standard with the DoD protocols when GOSIP is formally approved as a Federal Information Processing Standard. Two years thereafter, the OSI protocols would become the sole mandatory interoperable protocol suite; however, a capability for interoperation with DoD protocols would be provided for the expected life of systems supporting the DoD protocols. ..." \n\nA lot of study has already been done by the internet world on possible transitions and coexistence of the protocols. The following list is a series of RFCs already issued for that purpose: \n\nRFC 983 - ISO Transport Services on Top of the TCP. \nRFC 1006 - ISO Transport Services on Top of the TCP - Version 3. \nRFC 1039 - A DoD Statement on Open Systems Interconnection Protocols. \nRFC 1069 - Guidelines for the Use of Internet IP Addresses in the ISO Connectionless-Mode Network Protocol. \nRFC 1085 - ISO Presentation Services on Top of the TCP/IP-based Internets. \nRFC 1086 - ISO-TP0 Bridge between TCP and X.25. \nRFC 1090 - SMTP on X.25. \nRFC 1161 - SNMP over OSI. \nRFC 1195 - Use of OSI IS-IS for Routing in TCP/IP and Dual Environments. \nRFC 1238 - CLNS MIB for Use with Connectionless Network Protocol (ISO 8473) and End System to Intermediate System (ISO 9542). \nRFC 1240 - OSI Connectionless Transport Services on top of UDP: Version 1. \nRFC 1308 - Executive Introduction to Directory Services using the X.500 Protocol. \nRFC 1309 - Technical Overview of Directory Services using the X.500 Protocol. \nRFC 1327 - Mapping between X.400 (1988)/ISO 10021 and RFC 822. \nRFC 1328 - X.400 1988 to 1984 Downgrading. \nRFC 1330 - ESCC X.500/X.400 Tas
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Socket PORT...... IP of the destination.......
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Different protocols divide the network stack differently ( network stack - from where an application or program "hooks" in to the network at the software level down to the media connection { e.g. wires } and signaling) . Some protocols only use parts of the stack.\n\nDifferent layers of the stack do different processing depending on the protocol. For instance TCP/IP partitions the stack into 5 layers. NetBeui essentially only uses the upper half of the stack. WAN protocols rarely go above the global addressing area that is located about half way up the stack from the media ( IP area ). Usually WAN protocols stay around the bottom of the stack.\n\nIn essence data is divided into pieces at various layers to make it small enough to send and it is also "encapsulated" in different ways. Encapsulated can mean adding extra information in front of the data and/or behind the data. This information is used for different things for example making sure the data gets sent to the right place ( IP, AppleTalk, IPX ) or another example making sure the data that is sent has not been changed when it gets received ( Ethernet CRC check in the trailer ). This processing happens as the data passes from upper program to lower media at different levels depending on what the protocol's purpose is. The encapsulation is also "read" when the receiving machine receives, and the encapsulation essentially can contain instructions or necessary data for the receiving machine so that the receiving machine can send the original data properly up to the receiving program in the receiving machine. \n\nThere are also devices in between the two machines that read the different encapsulations around the data ( and possibly change it )so in between machines can do things like send the information along to another receiving device and making sure they are sending it to the right device.\n\nThis said, the TCP IP stack is a very common way of viewing the network. Another common way is the ISO's ( International Standards Organization's ) 7 layer OSI model.\n\nYou can find information all over the internet about the layers. For a good general overview go to http://en.wikipedia.org/wiki/TCP/IP\n\nRFCs( Request For Comments) give general to specific information about various protocols. You can find them at http://www.rfc-editor.org/ . Search for STD0001.\n\nThe ISO can be located at http://www.iso.org/iso/en/ISOOnline.frontpage\n\nThere are a lot of other standards bodies to search for but it might be wise to try to understand the TCP/IP model and the OSI model first.
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Kindly go through Tennanbaum Networking book, they ask most questions from it.\n\nSome of the ques i know are:\n1.7 layers of the network\n2.TCPIP protocol\n3.cables,fibres,etc\n4.encryption and cryptography\nand other topics in the above book
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Normally, when a TCP/IP application wants to send information, that information travels down the protocol layers to IP where it is encapsulated in an IP datagram. That datagram then passes down to the data link layer of the device's physical network for transmission to the next hop, on the way to the IP destination.\n\nHowever, one special range of addresses is set aside for loopback functionality. This is the range 127.0.0.0 to 127.255.255.255. IP datagrams sent by a host to a 127.x.x.x loopback address are not passed down to the data link layer for transmission. Instead, they “loop back” to the source device at the IP level. In essence, this represents a “short-circuiting” of the normal protocol stack; data is sent by a device's layer three IP implementation and then immediately received by it.\n\nThe purpose of the loopback range is testing of the TCP/IP protocol implementation on a host. Since the lower layers are short-circuited, sending to a loopback address allows the higher layers (IP and above) to be effectively tested without the chance of problems at the lower layers manifesting themselves. 127.0.0.1 is the address most commonly used for testing purposes.
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while connected to your isp...\n\nstart>run>type "command" for win9X or "cmd" for others and hit enter. at dos prompt type "ipconfig /all" and hit enter. all the info will be listed.
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All Internet traffic is TCP/IP (Transmission Control Protocol/Internet Protocol).  Everything you send to Hotmail, and everything they send back, is transported over TCP/IP.\n\nThe same is true for any web site, Instant Messaging application, music download, etc.\n\nThe rare exception is Voice over IP (like Vonage) which uses UDP/IP.  It's less reliable than TCP, but it's a simpler protocol and works well for the zillions of tiny packets that make up a phone call.
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Transmission Control Protocol - Internet Protocol