[ENet-discuss] Long Distance Packet Loss (maybe)?

[Alex Milstead]

Thanks a bunch, Lee! That did it. Still doesn't quite explain the 
"malformed packet" information I was receiving from wireshark, although 
since I'm actually getting the packets this time, I suppose that doesn't 
really matter much.

Cheers,
Alex

On 1/15/2010 12:25 PM, Lee Salzman wrote:
> enet_host_flush just sends the packet only once. If the packet gets 
> lost, enet_host_service ensures it gets resent until it is delivered.
>
> Lee
>
> Alex Milstead wrote:
>> On 1/15/2010 11:28 AM, Lee Salzman wrote:
>>> Are you regularly calling enet_host_service on the client?
>>>
>>> Lee
>>>
>>> Alex Milstead wrote:
>>>> Hey all,
>>>>
>>>> Just a heads up, (I don't know how reliable this is, exactly, but) 
>>>> I've been using a network packet monitoring tool call "wireshark" 
>>>> to monitor packets coming back and forth between client and server 
>>>> apps using an ENet wrapper I wrote.
>>>>
>>>> I'm using ENet to send a struct back and forth between machines. 
>>>> The struct itself isn't very big (only about 10 fields inside), and 
>>>> for the longest time sending it to and fro was no big problem. 
>>>> Recently, though, I've been testing out the server piece of the 
>>>> app(s) I'm writing, and according to wireshark, I'm receiving 
>>>> "Malformed Packets". I see this happening pretty frequently between 
>>>> machines when the client and server are in the same general 
>>>> (geographical) locale, however I've got a team member that is 
>>>> testing the client from Oregon (I'm in Georgia), and some seriously 
>>>> screwed up is happening. Every time he sends data, wireshark picks 
>>>> up that a packet is coming in, but ENet -never- hits the 
>>>> "ENET_EVENT_TYPE_RECEIVE" event on the server host that is 
>>>> servicing the connection.
>>>>
>>>> The basic break down of the apps ENet protocols are as follows 
>>>> (sans the client connecting to the server for the first time):
>>>>
>>>> Client code:
>>>> ...
>>>>
>>>> SendData(void *data)
>>>> {
>>>>    if (connected) // flag set to true when enet_host_connect and 
>>>> subsequent (enet_host_service && event.type == 
>>>> ENET_EVENT_TYPE_CONNECT) events are true
>>>>       ENetPacket *packet = enet_packet_create(struct_ref, 
>>>> sizeof(structReferenced), ENET_PACKET_FLAG_RELIABLE);
>>>>       enet_peer_send(server, channel, packet);
>>>>       enet_host_flush(connection);
>>>> }
>>>> ...
>>>>
>>>> Server Code:
>>>> ...
>>>> while (enet_host_service(connection, &event, connection_lifetime) 
>>>> >= 0 && !quit) {
>>>>        switch (event.type) {
>>>>            case ENET_EVENT_TYPE_CONNECT:
>>>>                cout << "A new client connected!";
>>>>
>>>>                break;
>>>>            case ENET_EVENT_TYPE_RECEIVE:
>>>>                ProcessPacket(event);
>>>>                break;
>>>>       }
>>>> }
>>>> ...
>>>>
>>>> The problem appears to be when packets are sent from the client 
>>>> machine in Oregon. Like I mentioned, wireshark is telling me that 
>>>> the packet actually made it, but the ENET_EVENT_TYPE_RECEIVE 
>>>> -never- occurs. Again, I'm not sure how reliable "wireshark" is, 
>>>> but it's telling me that the UDP packet being sent is "malformed". 
>>>> This doesn't seem to happen when I'm sending from a client machine 
>>>> that is geographically closer to the server (e.g. in my home, but 
>>>> sending requests to the frontal IP instead of a local IP), although 
>>>> wireshark still seems to report that the datagram sent from the 
>>>> closer machine is also sometimes "malformed".
>>>>
>>>>
>>>> Any ideas on what's happening/going wrong?
>>>>
>>>> Thanks for any help in advance.
>>>>
>>>> Cheers,
>>>> Alex
>>>>
>>> _______________________________________________
>>> ENet-discuss mailing list
>>> ENet-discuss at cubik.org
>>> http://lists.cubik.org/mailman/listinfo/enet-discuss
>> Yes. The method which calls "SendData", immediately calls 
>> enet_host_service afterward to listen for response packets from the 
>> server.
>>
>> Should I be using "enet_host_service(conn, &event, lifetime) && 
>> event.type == ENET_EVENT_TYPE_CONNECT" before sending a packet? I 
>> thought the purpose of enet_flush_host was to send off packets 
>> without having to service the host.
>> _______________________________________________
>> ENet-discuss mailing list
>> ENet-discuss at cubik.org
>> http://lists.cubik.org/mailman/listinfo/enet-discuss
>>
>
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