network-protocols

问题 import socket, sys if len(sys.argv) !=3 : print "Usage: ./supabot.py <host> <port>" sys.exit(1) irc = sys.argv[1] port = int(sys.argv[2]) sck = socket.socket(socket.AF_INET, socket.SOCK_STREAM) sck.connect((irc, port)) sck.send('NICK supaBOT\r\n') sck.send('USER supaBOT supaBOT supaBOT :supaBOT Script\r\n') sck.send('JOIN #darkunderground' + '\r\n') data = '' while True: data = sck.recv(1024) if data.find('PING') != -1: sck.send('PONG ' + data.split() [1] + '\r\n') print data elif data.find('

问题 I can see that stateful protocols lead to less botched together 'emulated state' like cookies. but testing becomes a lot harder to ensure that your implementation is correct and reconnects, and session continuations can be very hard to handle. Is it considered better practice to always use stateless protocols, or is it really domain specific? I think that authentication becomes easier when dealing with stateful protocols, but are there any other reasons you should use a stateful protocol? 回答1

问题 Does the HTTP protocol specify a max length for the ETag? 回答1: No. 14.19 ETag The ETag response-header field provides the current value of the entity tag for the requested variant. The headers used with entity tags are described in sections 14.24, 14.26 and 14.44. The entity tag MAY be used for comparison with other entities from the same resource (see section 13.3.3). ETag = "ETag" ":" entity-tag Examples: ETag: "xyzzy" ETag: W/"xyzzy" ETag: "" 回答2: No, an entity-tag is a quoted-string with

问题 I am currently trying to figure out how sms classes are correctly represented in SMPP. However I am by now completely confused by the standard and it's documentation. In normal sms we have Class0: Flash sms, which are shown on the display Class1: Normal Sms to be stored on the sim or internally in the device Looking at the SMPP spec, I first find the parameter data_coding in the submit_sm operation, which is used to set the DCS sent via MAP. As far as I understand this, if we want to

问题 SCTP has native multi-homing support which if I understand it correctly will automatically reroute your packets over a secondary NIC if the primary interface goes down. I duplicated this functionality with TCP by writing a custom routing deamon to modify the routing tables if my primary NIC goes down. I would like to try using SCTP instead. In Steven's Unix Network Programming V1 3rd Edition on page 288 it says: For this example, we use a one-to-many-style server. We make this choice for one

问题 I have a laptop that is connected to my organization's network using one or more network adapters. I'm not sure how to start this or where I should look for native python methods or other resources. I was wondering how can I discover all the network adapters or NICs I am connected to using python. I want to try to accomplish this without a 3rd party library but if I have to that is fine as well. I ultimately want to be able to write a tool that will continuously monitor the connectivity

问题 Currently I'm creating a server application to receive protocol-specific messages. I need to create tests to ensure that I've implemented the protocol correctly. Is this some kind of integration testing? If positive, can I make an integration testing with unit testing tools? And finally, what is the best way to create these kind of tests? 回答1: If you know what the correct responses are, then here's what I'd do: Separate the class responsible for the logic of handling the protocol from the

问题 Why does UDP have the field "UDP Length" twice in its packet? Isn't it redundant? If it is required for some kind of error checking, please provide an example. 回答1: From RFC 768: Length is the length in octets of this user datagram including this header and the data. (This means the minimum value of the length is eight.) The pseudo header conceptually prefixed to the UDP header contains the source address, the destination address, the protocol, and the UDP length. This information gives

问题 While transmiting data via localhost address or 127.0.0.1 which layers are used in the OSI model? I believe communication starts through application layer and goes down till some layer but no data goes through physical layer, or does any? 回答1: Traffic to 127.0.0.1 will be looped back by the internet layer of the TCP/IP model, which is matched in the OSI model by the Network layer. This is the layer where routing and address resolution take place. 回答2: I believe (although I'd be happy to be

问题 I am trying to set up a Multihop AdHoc 802.11g Network in ns-3. To get started I used the example 'wifi-simple-adhoc-grid.cc'. The example uses UDP, but I want to use TCP. Therefore I switched TypeId tid = ns3::UdpSocketFactory::GetTypeId(); Ptr<Socket> recvSink = Socket::CreateSocket (c.Get (sinkNode), tid); InetSocketAddress local = InetSocketAddress (Ipv4Address::GetAny (), 80); recvSink->Bind (local); recvSink->SetRecvCallback (MakeCallback (&ReceivePacket)); to TypeId tid = ns3: