Hello Ke Meng.
One important thing with IBR-DTN is, that the node must have discovered each other. The discovery mechanism uses broadcast/multicast UDP beacons to detect another node. If this is not working, a bundle never gets forwarded. To check if the nodes has discovered each other check the log output. There have to be NodeEvent saying node xyz is available. You can force this by define a static node like in the example configuration. But be aware that this defines a static node and will not work disruption tolerant.
To solve your issue, you should check if broadcast/multicast is working in your setup. You could use tcpdump to listen on UDP packets addressed to port 4551 and check if they arrive at the other host. That is the default discovery port in IBR-DTN.
Lets say something to the "localhost dtnping"-thing. An alias like localhost do not exist in IBR-DTN. To use dtnping locally, you have to call dtnping with the correct local hostname AND the application to send the bundles to. In your case this would be "dtnping dtn://OpenWrt/echo".
Best regards, Johannes Morgenroth
Am 17.02.2011 20:22, schrieb Meng, Ke:
Hi Johannes,
I'm trying to use ibr_dtn under openwrt, however failed to get through by dtnping. There are few guide about how to use ibr_dtn in the internet. Could you help me with that.
I compiled the openwrt with ibr_dtn and used it in the virtualbox. Two virtual machines were created with bridge to connect each other. The ping command is successful. However, the dtnping always failed. Here is one of the ibr_dtn configuraton:
local_uri = dtn://openwrt1.dtn routing = default blob_path = /tmp/ibrdtn/blobs storage_path = /tmp/ibrdtn/bundles statistic_type = stdout statistic_interval = 2 statistic_file = /tmp/ibrdtn.stats net_lan0_type = tcp net_lan0_interface = eth0 net_lan0_port = 4556 net_interfaces = lan0
By the way, the dtnping also failed to the localhost(127.0.0.1). Do you think there are other things I need to consider?
When I use debug mode, one side shows: Thu Feb 17 18:43:14 2011 NOTICE: BundleReceivedEvent: Bundle received [351283394.7] dtn://OpenWrt/echo-client -> dtn://openwrt1.dtn Thu Feb 17 18:43:14 2011 NOTICE: QueueBundleEvent: New bundle queued [351283394.7] dtn://OpenWrt/echo-client Thu Feb 17 18:43:14 2011 NOTICE: BundleEvent: bundle [351283394.7] dtn://OpenWrt/echo-client received Thu Feb 17 18:43:45 2011 NOTICE: BundleEvent: bundle [351283394.7] dtn://OpenWrt/echo-client deleted Thu Feb 17 18:43:45 2011 NOTICE: BundleExpiredEvent: Bundle has been expired [351283394.7] dtn://OpenWrt/echo-client
The other side shows nothing.
Thanks a lot.
Ke Meng