Re: [dtn-interest] problem of using discovery of ad-hoc mode

["Long, Darren" <[e-mail]>]

Hi Zhan,
 
My own experience with IP discovery is that it is ok when the associated network interface is always up, but can have issues when the interface goes down and IP discovery doesn't recover.  I suspect that the use of ad-hoc wireless connections causes this problem for you.  If you use external ethernet attached wifi devices rather than internal ones, this probably won't happen, but I've not tried that so I'm not sure.  With an internal adapter, you could try restarting the dtnd after the ad-hoc connection is made or use bonjour instead.
 
For bonjour on Linux (I assume that's what you are using), I've used avahi instead of the apple code and that works fine, although a tweak is needed in the avahi.conf file to disable the additional service cookie, i.e. set add-service-cookie=no
 
As far as I can tell, the main difference (apart from the fact that bonjour is resilient to intermittent network connectivity) is that (as I understand it) bonjour works only on the local subnet, but IP discovery can be used for unicast discovery through routers.
 
Hope this helps.  You should probably post this kind of question to dtn-users rather than dtn-interest though.
 
Cheers,
 
Darren

-----Original Message-----
From: [e-mail] [mailto:[e-mail]]On Behalf Of Zhan Jie
Sent: 23 November 2007 06:02
To: [e-mail]
Subject: Re: [dtn-interest] problem of using discovery of ad-hoc mode


Hi, 

i had set up 2 nodes as ad-hoc network as according to the previous email. 

Situation 1 

Node 1(IP:192.168.10.1) --------- Node 2( Ip: 192.168.10.2) 

i am able to ping each other in the network. 

The configuration file for each node is as follows: 

Node 1 
route set type dtlsr 
route local_eid "dtn://one.dtn" 
interface add tcp0 tcp 
interface add udp0 udp 
discovery add ipdisc0 ip port=2000 addr=192.168.10.1 
discovery announce tcp0 ipdisc0 tcp interval=5 interval=5 

Node 2 
route set type dtlsr 
route local_eid "dtn://two.dtn" 
interface add tcp0 tcp 
interface add udp0 udp 
discovery add ipdisc0 ip port=2000 addr=192.168.10.2 
discovery announce tcp0 ipdisc0 tcp interval=5 interval=5 

There will not be error message. However, the DTN node still not able to detect each other. 

Situation 2 

when i connect both laptop to a router as follows: 

Node 1(Ip:192.168.5.100) ---LAN Connection-- [ROUTER] --LAN Connection-- Node 2 (Ip: 192.168.5.101) 

The configuration file is as follows: 

Node 1 
route set type dtlsr 
route local_eid "dtn://one.dtn" 
interface add tcp0 tcp 
interface add udp0 udp 
discovery add ipdisc0 ip port=2000 
discovery announce tcp0 ipdisc0 tcp interval=5 interval=5 

Node 2 
route set type dtlsr 
route local_eid "dtn://two.dtn" 
interface add tcp0 tcp 
interface add udp0 udp 
discovery add ipdisc0 ip port=2000 
discovery announce tcp0 ipdisc0 tcp interval=5 interval=5 

In Situation 2, the node 1 DTN is able to locate Node 2 DTN. Thus i can able to send file or message to Node 2. However i am not able to do that in Situation 1 as Node 1 cannot locate Node 2. is that any mistake in the configuration file?

another question is that what is the difference between discovery_bonjour and ipdisc0? 
And discovery only used for neighbor protocol?