[ns] Help Scheduler: Event UID not valid!

[Zhou Ya Jin]

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Question 1: 

Scheduler:: Event UID not valid! 

Answer: 

Each event in NS2 has a unique UID. The scheduler toggles the UID twice, 
once during dispatching and once during scheduling. Thus, the event has a 
positive UID after being scheduled and a negative one before being scheduled. 
If the event has been scheduled but not dispatched, then it will have a 
positive UID and cannot be scheduled again. 

In implementing a new protocol, this error can happen in two cases:

1. You are using timers. When a timer is scheduled again without the 
previous schedule expiring - Trace which timer is scheduled and when it 
will expire.

2. You are dealing with packets. A packet is also a kind of event to be 
scheduled and a UID is associated with it. When you create a 
copy or alloc again before freeing it, due to the same packet with a positive 
UID, it cannot be scheduled again. 
----- Original Message ----- 
From: "Cristina Marisol Ortiz De La Roche" <cristina-marisol.ortiz-de-la-roche at polymtl.ca>
To: <ns-users at ISI.EDU>
Sent: Friday, May 19, 2006 6:45 AM
Subject: [ns] Help Scheduler: Event UID not valid!


> 
> 
> 
> Hi!!!!
> I'm working on a wireless topology and NS-2.29 (configure in linux) for my
> research work. When I try to simulate a bidirectionnal communication between a
> wireless endpoint and a wireline endpoint with 11 Mbps and smalls packets (size
> 200 bytes), I'm getting this error:
> 
> Scheduler: Event UID not valid!
> 
> This error doesn't exist if the communication is only in one way.
> 
> My configuration is without the use of RTS/CTS mechanism. Can someone help me
> with this problem??? Any bug that can help???
> 
> Thanks!!!
> 
> rgds,
> Cristina
>