Subject: Re: Timers associated with Fragmentation and reassembly.
To: Gurubaran T- CTD, Chennai. <>
From: Perry E. Metzger <>
List: netbsd-users
Date: 11/05/2002 10:47:50
"Gurubaran T- CTD, Chennai." <> writes:
>          I am a newbie. I need to know the various timers associated with
> fragment reassembly. Also if possible timers assocaited with IP input. I am
> using a OS warppers for timers developed in c++ for the stack ( NetBSD stack
> with some of the OS stuff freed from the OS ). The stack is up and when i
> ping with packets ( larger than MTU )that require fragmentation and
> reassembly, one out of every five requests gets timed out. whereas this is
> not the case with packets whose size is less than the MTU.  

It sounds like you are using a NetBSD stack without the rest of
NetBSD, presumably in some sort of embedded context. Anything we could
thus tell you might not apply to the C++ based NetBSD derived stack
you are running. You have to make a lot of changes to rip a stack free
of its operating system.

In any case, though, the best kind of documentation is the source
code. You can easily search for instances of timer setup with grep and
other tools and determine what timers may be used where in your code
base. I would also recommend Stevens, "TCP/IP Illustrated", Volume 2
as a good general introduction to BSD network stacks.