[ns] Changing the IP header

Hello, I'm working on a project where i need to add a new field to the existing IP header and bind it so that i can pass some value from tcl script.Can any one give me a detailed procedure on how to do it as I'm relatively new to NS2. I am currently using ns-2.33 . I tried to do the same

[ns] Fixing the TTL value

Hello, I need to set the ttl value to constant value of choice for all the packets transmitted.I need to know where should i do it?Please can anyone tell me how to do it.

[ns] how to implement a buffer

Hello, I'm working on a project where i need to store (I even need to sort them according to seq no in the buffer) all the packets received by a node and manipulate them before forwarding .I need to know how a buffer is implemented at a node.Please anyone help me. Thanks, Saikrishna

[ns] how to call multiple targets to receive a packet.

Hello, I need to simulate a scenario where a node on receiving a packet will send it out on all the out going links.I do not want to use multicast protocols due to some other issue.Can any one help me with implementing it?. Thank you, Regards -Saikrishna