> > ---------------------------------------------------------------------- > > Message: 1 > Date: Mon, 9 Nov 2009 10:25:46 +0800 (CST) > From: galaxy-huang <[email protected]> > Subject: [ns] Is it necessary to remove the unused packet headers? > To: ns <[email protected]> > Message-ID: > <25185197.124361257733546417.javamail.corem...@bj163app121.163.com> > Content-Type: text/plain; charset=gbk > > hi, everyone, > In chapter 12 of THE NS MANUAL, the author wrote that "By > default, ns includes ALL packet headers of ALL protocols in EVERY > packet in your simulation. This is a LOT of overhead ..." > But i find that many ns tutorials, experiments never mentioned > this problem. my question is, Is it necessary to remove the > unnecessary headers when we are doing simulations, especially when > need to calculate delays and throughputs? Is the BIG unnecessary > headers affect the packet transmit time(when calculate the timeout > of the event, are the length of all headers taken into account )? > Thank you in advance! >
No it is not necessary to remove the unnecessary headers. But it does reduce the memory consumption and improve the speed doing so. Just make sure that you don't cancel packet headers that you need. If you do, the simulation won't run anyways. The Common headers is always needed. The BIG unnecessary headers have no impact on the packet txtime. The size of the simulated packet (not the ns-2 Packet object, but the simulated protocol data unit) is written in the Common header. The transmission time is written in Common header as well. You seem to be confusing the ns-2 Packet class instantiations with simulated protocol data units. Guray
