Netdemo and ARP protocol

Ian Caddy ianc at microsol.iinet.net.au
Fri Sep 13 02:18:18 UTC 2002


Hi Mario,

I am not quite sure what processor, or Ethernet chip you are using so it 
is hard to give detailed information but I have a couple of pointers for 
you.

1. Your physical address that you are using is a multi-cast address and 
shouldn't be used for your normal Ethernet address.  The 6 byte physical 
address should NOT set the lowest bit of the first byte, i.e. your first 
byte is 0x31.  The 1 indicates a multicast address.  This will cause all 
sorts of problems.  I recommend that you set this byte to 0.  Also, if 
you want to talk to real pieces of equipment you will have to get a 
proper Ethernet address at some stage.

2.  Are you writing your own Ethernet driver or just trying to get one 
of the existing drivers running?

regards,

Ian Caddy


Mario Vieira wrote:

>
> Hi, I am a newbie with RTEMS and I need help.
>
>
> I am porting RTEMS to a board from quicklogic. I'm testing the network 
> with the netdemos-4.5.0/netdemo and I find out (printing the mbuffer) 
> that the initial ARP packet that is sent is incorrect.
> Below I send the capture packet that is exactly like the mbuffer:
>
>
> Frame 1 (60 on wire, 60 captured)
>     Packet Length: 60 bytes
>     Capture Length: 60 bytes
> Ethernet II
>     Destination: ff:ff:ff:ff:ff:ff (ff:ff:ff:ff:ff:ff)
>     Source: 31:32:33:34:35:36 (31:32:33:34:35:36)
>     Type: ARP (0x0806)
>     Trailer: 0000C1888F010000000004D200090328...
> Address Resolution Protocol (opcode 0x0604)
>     Hardware type:  (0x0000)                                 <- HERE short
>     Protocol type: Unknown (0x0001)
>     Hardware size: 8
>     Protocol size: 0
>     Opcode: Unknown (0x0604)
>     Sender hardware address: 0001313233343536
>     Target hardware address: C1888F0100000000  
>
>
> The "HERE short" isn't supposed to be there. From there the codes are 
> correct but moved 2 bytes.
>
> I look at the procedure to send out ARP Requests but I could see what 
> is wrong.
> Please help me.
>
> Thanks in advance,
> Mário Vieira


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