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Re: [lwip-devel] How to understand TCP_SND_BUF
From: |
narke |
Subject: |
Re: [lwip-devel] How to understand TCP_SND_BUF |
Date: |
Wed, 28 Dec 2011 08:31:53 +0800 |
On 28 December 2011 02:04, Simon Goldschmidt <address@hidden> wrote:
> narke <address@hidden> wrote:
>
>> I found the value of TCP_SND_BUF was assigned directly to snd_buf
>> attribute when a new pcb was allocated. Then I lost understanding
>> why this variable should be used.
>>
>> It's different with snd_wnd, which is dynamically changed after a new
>> value is advertised from the peer end.
>> It's also has nothing to do with memory space of sending pbufs, which
>> is determined by MEM_SIZE constant.
>
> You got the point without noticing it: snd_buf does limit the memory space of
> sending pbufs, not for the whole stack but for single connections. It is used
> to prevent one connection from using up all memory.
>
> Simon
>
Got it! Very clear.
--
Life is the only flaw in an otherwise perfect nonexistence
-- Schopenhauer
narke
public key at http://subkeys.pgp.net:11371 (address@hidden)