Create new attribute!

[ns3.us...@gmail.com]

Hye!
I need help creating a new attribute of type std::set for a class created by me. How can I create an attribute like this?
What's the easiest way to transmit a std::set as a parameter?
Thank's in advance.

[Konstantinos]

Hi,

IMHO, the std::set is similar to the std::vector which has already been discussed in the list. 

std::vectors can not be 'set' as attributes (https://groups.google.com/d/msg/ns-3-users/yFri5ZbKDvU/jDAPJ1LqvzYJ) 

Now, when you refer to 'transmit' a set you mean in a packet? I do not know if this is the easiest, but this is the correct way: you need to iterate on each element of the set and write it onto the packet. You will also need one extra field in the packet to identify how many elements you need to read when you receive this packet.

[ns3.us...@gmail.com]

Thank you for your answer, Konstantinos.
Now I understand why it wasn't working..

I have pairs like: pair<Ipv4Adress, string> used to represent nodes (to associate the IP adress and a string name). With these pairs I create a set of pairs. I need to transmit the set in the helper constructor and therefor to install the helper on the created nodes so that they could process the set of pairs representing neighbour nodes.
I will also need to send the set of pairs in the payload of the packets, although I don't know exactly how to do this..

[Konstantinos]

As I said, this issue is very similar to the 'std::vector'

The next is some guidelines/pseudocode:

Create your 'set';

Create your helper;

Set your 'set' in your helper; e.g. using the pass by reference.

Use the 'set' in the helper;

[pdbarnes]

The only technical requirement to inventing a new Attribute type is that you can serialize/deserialize to/from a string. In principle a vector could be serialized as "value0|value1|..." assuming the elements themselves could be serialized. A set could be serialized the same way. The difficult bit will be the templates to serialize arbitrary elements.

> IMHO, the std::set is similar to the std::vector which has already been discussed

> in the list. Std::vectors can not be 'set' as attributes
> (https://groups.google.com/d/msg/ns-3-users/yFri5ZbKDvU/jDAPJ1LqvzYJ)

[pdbarnes]

Take a look at EpidemicRouting, which has nodes exchange packets containing a vector of packet ids.
Peter

[ns3.us...@gmail.com]

Thank's for replying!

I've tried to send std::set as a reference, but it gave me some errors when I tried processing the set.

I've also looked at the epidemic routing, but I still don't know how to solve my problem.