[ECOS] BOOTP/DHCP delay question

Ilko Iliev iliev@caretec.at
Tue Feb 1 16:15:00 GMT 2005


Hi,

The problem is that the switch needs 1.5-1.7 seconds to check for 
network loop.
The init_all_network_interfaces() with DHCP resets on the network device 
many times:
- in static constructors
- in do_dhcp()
- in cyg_net_int()

The result ist that the init_all_network_interfaces() needs 5 seconds to 
initialize with DHCP and first network access needs other 5 seconds.
That mean: the board ist working after more than 10 seconds.

Any suggestions on how to make it faster?

regards
ilko


John Newlin wrote:

>Another possiblity, is some switches do checks for network loops when
>a port comes active, and this can take a couple of seconds.
>
>
>
>On Mon, 31 Jan 2005 23:26:18 +0100, Andrew Lunn <andrew@lunn.ch> wrote:
>  
>
>>On Mon, Jan 31, 2005 at 06:07:10PM +0100, Ilko Iliev wrote:
>>    
>>
>>>Hi,
>>>I use BOOTP and DHCP to configure my target IP, in both cases this
>>>process takes about 5 secs.
>>>So the questions are:
>>>1. What is the purpose of this delay?
>>>2. Can this be made immediately, i.e. not waiting for a timeout?
>>>      
>>>
>>Look at the packets being transfered. I've seen a few different things
>>happen:
>>
>>1) The dhcp server allocates an IP address and then sends out an ARP
>>for that address to see if anybody else is already using it. It then
>>waits a couple of seconds to see if anybody replies to the ARP before
>>giving the IP address to the dhcp client.
>>
>>2) The dhcp client code passes the first packet to the ethernet device
>>before it is fully initialised. The ethernet device then drops the
>>packet. Some time later the dhcp client does a retry which does make
>>it out onto the wire.
>>
>>It could be one of these is happening.
>>
>>        Andrew
>>
>>--
>>Before posting, please read the FAQ: http://ecos.sourceware.org/fom/ecos
>>and search the list archive: http://ecos.sourceware.org/ml/ecos-discuss
>>
>>
>>    
>>
>
>  
>


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