Re: [dtn-interest] What's the actual effect of using custody transfer?

[Martin Galvan <[e-mail]>]

Thanks a lot guys! So basically, the difference is that the sender has to
keep its copy of the bundle until it receives an acknowledgement from the
destination node, while in custody transfer it's the custodian node that
has to keep its copy? What if C receives the bundle, but there's no link
for it to send its acknowledgement back to A? Will A (or B, if it accepted
custody) have to keep its copy of the bundle indefinitely in storage?


2014-05-14 12:20 GMT-03:00 Martin Galvan <[e-mail]>:

> Hi everybody! I'm reading a bit on DTN and I have a doubt about what
> custody transfer actually does. From what I've read, a node that accepts
> custody of a bundle promises it won't delete the bundle until it can
> forward the bundle to either its destination or another node that accepts
> its custody. However, I don't see what would be the difference between
> doing that and not using custody transfer. Isn't the whole purpose of a
> store-and-forward mechanism to do just that?
>
> For example, let's assume we have three nodes, A, B and C. There's no
> end-to-end path from A to C, and A is directly connected to B.
>
> A----->B     C
>
> If I understood custody transfer right, if A wants to send C a bundle
> using custody transfer, it will request B to accept custody of the bundle;
> if B accepts it will store the bundle until a link to C can be established.
> Once that happens, B will then forward the bundle to C and delete it once
> it's reached its destination.
>
> What would happen if A didn't want to use custody transfer?
>
> Thanks a lot!
>