October 2012 - Ibr-dtn - lists.ibr.cs.tu-bs.de

Queue Management and Forwarding Policy implementation
by Guilherme Rolim 02 Nov '12

02 Nov '12

Good day, I am interested in modifying the IBR-DTN code. In doing so, I plan to make changes on the DTN Queue Management and Forwarding Policy, however, I don't know which classes to modify our work with. Could someone point me at the right direction? Thanks in advance, Guilherme Rolim

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Re: [ibr-dtn] Send a message to multiple recipients at a time
by Sergey Sireskin 23 Oct '12

23 Oct '12

Hi Till, Thank you for the detailed answer, it is very helpful, and looks like a complete recipe! I think someone should collect all recipes and bits of knowledge from the mailing list in a single place like wiki or something. Yes, I have got a large network with routing and no multicast support - this is exactly my case. Are the numbers 7 and 30 hardcoded constants somewhere in IBR DTN sources, and is it possible to change, for example, 7 to 3 for testing purposes, in order to not set up extra nodes? I suppose that it is possible to block port 9999 from the Internet with the help of a firewall in case if there is one host, which is part of the DHT and connected to the Internet, am I wrong? Best regards, Sergey Sireskin Mon, 22 Oct 2012 18:31:23 +0200 от Till Lorentzen <lorentze(a)ibr.cs.tu-bs.de>: Hi Sergey, I'll try to answer your third question (like Sebastian has done already) > 3. Does Bittorrent DHT discovery and routing need (any) nodes to be connected to the Internet? > If yes, is it possible to setup a DHT server in the Intranet, which is isolated from the Internet, > and make IBR-DTN use it? The main idea of the DHT discovery is to find nodes across the internet. So, yes, if you want to use this feature, you should be in a large network. It doesn't have to be the internet, but the DHT only works with more than 7 nodes. And it tries to request for 30 nodes, until it will break up bootstrapping for more nodes. So if you have got a large network with multiple subnets and routing between the subnets, but no multicast support between the subnets, then you could use the DHT. If you would like to setup such a system, this should be the setting of the DHT nodes: dht_enabled = yes dht_bootstrapping = no dht_bootstrapping_ips = 10.0.0.1 9999; The "10.0.0.1 9999" should be replaced by the IP and DHT Port of one available node. You could give a list of probably available nodes as well: dht_bootstrapping_ips = 10.0.0.1 9999; 10.1.0.1 9999; 10.2.13.34 1234; This should be all you need to build your own "private" DHT in a network, which is completely disconnected from the internet. If it is not disconnected from the internet. There is no mechanism to block this nodes! Only if one node connects to any node in the internet, this contact will be propagated across the whole "private" DHT! If your nodes are all in the same LAN with IP broadcast/multicast support, then you don't need the DHT. So you can simply disable it and use the normal neighbour discovery instead. To disable the DHT, simply edit the line at ibrdtn.conf: dht_enabled = no If you have got one host, which is part of the DHT and connected to the internet and you would like to prevent this node to announce all of its neighbours to the internet, then you have got two possibilities: Deactivating neighbour announcements completely on the node with the active DHT: dht_allow_neighbour_announcement = no Or a "private" node can publish, that he shouldn't be announced by anyone in the neighbourhood by setting: dht_allow_neighbours_to_announce_me = false _BUT_: This doesn't prevent from beeing connected from "outside". Like Sebastian already said, if any DHT node has got connection to you, they will communicate with each other and will try to exchange their DHT neighbour nodes. I hope, this will help you with your setup! Best regards, Till Lorentzen -- !! This message is brought to you via the `ibr-dtn' mailing list. !! Please do not reply to this message to unsubscribe. To unsubscribe or adjust !! your settings, send a mail message to <ibr-dtn-request(a)ibr.cs.tu-bs.de> !! or look at https://www.ibr.cs.tu-bs.de/mailman/listinfo/ibr-dtn.

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Send a message to multiple recipients at a time
by Sergey Sireskin 23 Oct '12

23 Oct '12

Hello dear IBR-DTN authors, I was unable to find any man pages, documentation or HOW-TOs on IBR-DTN, so the only place for asking my stupid questions is this mailing list, sorry. Here are my questions. 1. Is it possible to send a message to multiple recipients at a time, I mean something like multicast or group messages, in order to save bandwidth? 2. Changelog states that both reactive and proactive fragmentation are supported. How does IBR-DTN choose which fragmentation type to be used? 3. Does Bittorrent DHT discovery and routing need (any) nodes to be connected to the Internet? If yes, is it possible to setup a DHT server in the Intranet, which is isolated from the Internet, and make IBR-DTN use it? Best regards, Sergey Sireskin

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Re: [ibr-dtn] IBR-DTN installation
by Johannes Morgenroth 17 Oct '12

17 Oct '12

Hello Dimitrios Giotas, the easiest way would be to use the pre-compiled repositories. Once you have done your first steps with IBR-DTN, you can try to compile it on your own if that is necessary. Kind regards, Johannes Morgenroth Am 17.10.2012 13:08, schrieb Dimitrios Giotas: > Dear Mr. Morgenroth, > > my name is Dimitris Giotas.I am a student in Democritus University of > Thrace,Greece. > My professor has assigned me a project concerning your DTN > implementation,and I was wondering if you could assist me in my first steps. > I am going through tour wiki/download section and I am trying to install > the daemon.After installing all the required libraries,including the > optional ones,I tried > to install the daemon from source,both manually and by calling the script.I > installed the binaries in /home/dimitris/IBR-DTN and the I opened the > terminal in that folder.I then ran the dtnd command to start the daemon > with the default configuration but I get the message : "dtnd: command not > found". Is there any way you could assist me? > > I am currently running xUbuntu 12.04.Should I try the xUbuntu 12.04 > repository as well? > > > Thank you for your time, > Dimitris Giotas > -- Johannes Morgenroth Institut fuer Betriebssysteme und Rechnerverbund Tel.: +49-531-391-3249 Muehlenpfordtstrasse 23 Fax.: +49-531-391-5936 TU Braunschweig D-38106 Braunschweig

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Excessive file copies in IBR-DTN?
by Sergey Sireskin 08 Oct '12

08 Oct '12

Hello, IBR-DTN developers and users! I suspect that IBR-DRN does excessive work on copying files while doing dtnrecv. Here is what I do. 1. On the node2 I start dtnrecv --file /var/tmp/1.iso --name file 2. On the node1 I start dtnsend dtn://node-2.dtn/file /media/1.iso Then in another console on node2 I look, what does IBR-DTN do. 1. It stores the data, received, from node1 to a blob file in /var/spool/dtnd/blobs/ 2. Than it copies that blob file to a bundle file in /var/spool/dtnd/bundles/ 3. Than it copies the bundle file to the destination file /var/tmp/1.iso Steps 1 and 2 look ok to me. But why use bit-by-bit copy on step 3 instead of just move (mv) the bundle file to the destination file without the expensive data transfer? This excessive data copying consumes memory to store the whole bundle and takes more time. My node2 has 2Gb RAM. The file that I send (1.iso) is 1.2Gb. RAM gets exhausted on the step 3, and dtnrecv fails with error message "Aborted". So I have two proposals. 1. Implement better error reporting, e.g. "Not enough memory to copy file." instead of "Aborted." 2. Move bundle file to the destination file instead of copying it. ------------------------------------------------------------------------------------------------------------------------------- My IBR-DTN config: local_uri = dtn://node-2.dtn logfile = /var/log/ibrdtn.log timezone = +4 limit_blocksize = 0 user = dtnd blob_path = /var/spool/dtnd/blobs storage_path = /var/spool/dtnd/bundles limit_storage = 5G discovery_announce = 0 net_interfaces = eth0 net_rebind = yes net_autoconnect = 60 net_eth0_type = tcp net_eth0_interface = eth0 net_eth0_port = 4556 net_eth0_discovery = yes routing_forwarding = yes static1_address = 192.168.150.38 static1_port = 4556 static1_uri = dtn://node-1.dtn static1_proto = tcp static1_immediately = yes dht_enabled = yes dht_bootstrapping = yes Best Regards, Sergey Syreskin

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Re: [ibr-dtn] Ibr-dtn Digest, Vol 26, Issue 8
by gjohnson＠ltsnet.net 03 Oct '12

03 Oct '12

Hello, I also got a segmentation fault when trying to run my statically built executable. I debugged the segmentation fault and there was a line in EID.cpp (in ibrdtn/data folder) that was causing it. I changed that line and things worked after that. I'm not sure if you are getting a segmentation fault for the same reason, but below is the change I made to the default constructor that fixed things for me EID::EID() //: _scheme(DEFAULT_SCHEME), _ssp("none") // { //cout << "about to assign to _scheme" << endl; //cout << " DEFAULT_SCHEME = " << DEFAULT_SCHEME << endl; _scheme = "dtn"; _ssp = "none"; } Regards, Gleneesha > Send Ibr-dtn mailing list submissions to > ibr-dtn(a)ibr.cs.tu-bs.de > > To subscribe or unsubscribe via the World Wide Web, visit > https://www.ibr.cs.tu-bs.de/mailman/listinfo/ibr-dtn > or, via email, send a message with subject or body 'help' to > ibr-dtn-request(a)ibr.cs.tu-bs.de > > You can reach the person managing the list at > ibr-dtn-owner(a)ibr.cs.tu-bs.de > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of Ibr-dtn digest..." > > > Today's Topics: > > 1. Re: How to build native dtnd binary for Android from source? > (Yoshimi Fujii) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Thu, 27 Sep 2012 20:30:11 +0900 > From: Yoshimi Fujii <yfujii(a)kke.co.jp> > Subject: Re: [ibr-dtn] How to build native dtnd binary for Android > from source? > To: ibr-dtn(a)ibr.cs.tu-bs.de > Message-ID: <506438C3.1020503(a)kke.co.jp> > Content-Type: text/plain; charset="iso-2022-jp" > > Hello, > > We are still trying to build dtnd for Android using buildroot. > Build seemed to be successful and 'file dtnd' shows: > > "ELF 32-bit LSB executable, ARM, version 1 (SYSV), statically > linked, not stripped". > > However, when we run the binary, cause "Segmentation fault". > What's wrong with us? > > We built very simple application like "hello world" using > buildroot and it runs on Android successfully. > > Attached is the config file which we used for building dtnd. > > Thanks, > Yoshimi Fujii > >

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