[pox-dev] Defining Dictionary in POX controller

[Sayed Qaiser Ali Shah]

Hello Murphy actually I am working on Traffic Engineering. I am now
learning that how to forward traffic when we have dictionary on controller.
I want to forward some entries of dictionary via queue-1 and some entries
via queue-2. For this I have created dictionary and it created successfully
with you help. Those entries of dictionary contain Source Mac Address and
Destination Mac address. I created 2 queues on Interface 1 of switch. I
then Pinged host 2 from host 1 and host 1 from host 3. It inserted four
entries in dictionary created on controller. Entries in Dictionary are
{1: (EthAddr('00:00:00:00:00:02'), EthAddr('00:00:00:00:00:01')),
 2: (EthAddr('00:00:00:00:00:01'), EthAddr('00:00:00:00:00:02')),
 3: (EthAddr('00:00:00:00:00:01'), EthAddr('00:00:00:00:00:03')),
 4: (EthAddr('00:00:00:00:00:03'), EthAddr('00:00:00:00:00:01')) }
Dear Murphy you asked earlier that you didn't get what I wanted to do. I
think that I am just explaining it in easy way that I just want to forward
two entries of dictionary via queue-1 and other 2 entries of dictionary via
queue-2. I am just doing practice on different techniques of Traffic
Engineering.  I used the following code for forwarding traffic via queues:

if self.macaddrtable=='':      //When we have no entry in macaddrtable
dictionary
        queue=1
        msg.actions.append(of.ofp_action_enqueue(port = port, queue_id =
queue))
else:
    for a in self.macaddrtable:
         if a<=2:
            queue=1
            msg.actions.append(of.ofp_action_enqueue(port = port, queue_id
= queue))
         elif a>2:
            queue=2
            msg.actions.append(of.ofp_action_enqueue(port = port, queue_id
= queue))

The code worked fine and forwarded traffic via desired queues but after
about 10 seconds of pinging, duplicate packets were detected. I don't know
why duplicate packets were detected. Can you please tell the reason?


On Tue, Nov 12, 2013 at 2:00 AM, Murphy McCauley
<murphy.mccauley at gmail.com>wrote:

> It's still hard for me to answer questions since I still don't know what
> you're really trying to accomplish here.
>
> If you want entries to time out on the switch, set timeouts when
> installing the table entry (sending the flow_mod).  If you want
> notifications when flows are removed on the switch, that's also an option
> you can set when installing the entry; then listen to the FlowRemoved event
> to tell when it has actually happened.
>
> I'm not sure what you mean by "exact mac".  Your code records the address
> the packets were sent to.  If they were sent to the broadcast address,
> then... that's the destination.
>
> -- Murphy
>
> On Nov 11, 2013, at 9:42 AM, Sayed Qaiser Ali Shah <
> 11msitqshah at seecs.edu.pk> wrote:
>
> Thank you so much Murphy for your help. I did it the way you explained.
> But how can I refresh entries in the table. i.e. how to set idle timeout
> and hard timeout for this so that the table can be refreshed or how the
> entries can be updated when a flow is removed from flow table on Switch.
> Another Problem is:
> The code is as below.
>
> if (packet.src,packet.dst) not in self.macaddrs and
> (packet.dst,packet.src) not in self.macaddrs:
>         self.macaddrs.add((packet.src,packet.dst))
>         self.macaddrtable[f_id]=(packet.src,packet.dst)
>         f_id=f_id+1
> print "Mac Table is "
> print self.macaddrtable
>
> When I created a topology with 3 hosts the following result was shown
>
> Mac Table is
> {1: (EthAddr('00:00:00:00:00:01'), EthAddr('ff:ff:ff:ff:ff:ff')), 2:
> (EthAddr('00:00:00:00:00:02'), EthAddr('00:00:00:00:00:01')), 3:
> (EthAddr('00:00:00:00:00:03'), EthAddr('00:00:00:00:00:01')), 4:
> (EthAddr('00:00:00:00:00:02'), EthAddr('ff:ff:ff:ff:ff:ff')), 5:
> (EthAddr('00:00:00:00:00:03'), EthAddr('00:00:00:00:00:02'))}
>
> The result I expected is little bit different in terms of broadcast
> address. Like in 1 destination mac is ff:ff:ff:ff:ff:ff but I was expecting
> 00:00:00:00:00:02 and similar is the case with some other entries as well.
> Is there any way so that I can get desired exact mac, not broadcast?
>
>
>
> On Sun, Nov 10, 2013 at 5:00 AM, Murphy McCauley <
> murphy.mccauley at gmail.com> wrote:
>
>> It sounds like you need to record them as a pair to get what you want, so
>> ... put them in as a pair.
>>
>> It looks like I may have been responsible for the problem you were seeing
>> -- a little typo inserted an errant right square bracket.  Try:
>> self.macaddrs.add((packet.src,packet.dst))
>>
>> It's still not clear from context whether ordering matters to you (is A
>> sending to B the same as B sending to A?).  If it isn't, you might want to
>> sort the two addresses or just check for both...
>>
>> if (packet.src,packet.dst) not in self.macaddrs and
>> (packet.dst,packet.src) not in self.macaddrs:
>>
>> -- Murphy
>>
>> On Nov 9, 2013, at 3:32 PM, Sayed Qaiser Ali Shah <
>> 11msitqshah at seecs.edu.pk> wrote:
>>
>> Thank you so much Murphy. I tried it but got little problem in add
>> function i.e. when I used
>> self.macaddrs.add((packet.src,packet.dst])) it generated error in this
>> function then I tried
>> self.macaddrs.add(packet.src,packet.dst)
>> It also generated an error that add must have 1 argument where as 2
>> given. Then I tried
>>
>> if (packet.src,packet.dst) not in self.macaddrs:
>>   self.macaddrs.add(packet.src)
>>   self.macaddrs.add(packet.dst)
>>   self.macaddrtable[f_id]=(packet.src,packet.dst)
>>   f_id=f_id+1
>>
>> It didn't generate an error and I didn't get any repeated result but
>> there was some problem in the code I got results as below.
>> When I ping host1 from host 2 it added record in dictionary. Then I ping
>> host 3 from h1 record was inserted again but the problem was, as record of
>> host 1, host 2 and host 3 was saved in macaddrs and two records were there
>> but when I pinged the hosts present in macaddrs i.e. 1, 2, 3 like I ping
>> host 2 from h3 as record was not present in macaddrtable still record was
>> not added to dictionary. It is because addresses are saving in macaddrs one
>> by one individually i.e. first source and then destination address. When
>> packet arrives controller it checks for source and destination address in
>> macaddrs as when there are individual record of each host it then doesn't
>> execute IF body because source and destination addresses are already there
>> as individual address. What to do with this???? Kindly help.
>>
>>
>> On Sun, Nov 10, 2013 at 3:26 AM, Murphy McCauley <
>> murphy.mccauley at gmail.com> wrote:
>>
>>> One possible answer is that you should keep a set of the ones you've
>>> added so far...
>>> self.macaddrtable = {}
>>> self.macaddrs = set()
>>>
>>> ...
>>>
>>> if (packet.src,packet.dst) not in self.macaddrs:
>>>   self.macaddrs.add((packet.src,packet.dst]))
>>>   self.macaddrtable[f_id]=(packet.src,packet.dst)
>>>   f_id=f_id+1
>>>
>>>
>>> There might be better things to be done, but it's impossible to say
>>> without knowing more (e.g., what you're trying to accomplish, what f_id is
>>> used for, etc.).
>>>
>>> -- Murphy
>>>
>>> On Nov 9, 2013, at 10:35 AM, Sayed Qaiser Ali Shah <
>>> 11msitqshah at seecs.edu.pk> wrote:
>>>
>>> > Hello everybody,
>>> >
>>> > I have defined dictionary in POX controller and I by the name
>>> addrtable and I am saving two things in this dictionary i.e. Source mac and
>>> destination mac. What I have done is
>>> >
>>> >     self.macaddrtable = {}
>>> > ...
>>> >     f_id=1
>>> >     self.macaddrtable[f_id]={packet.src, packet.dst}
>>> >     print self.macaddrtable
>>> >     f_id=f_id+1
>>> >
>>> > It is saving source mac and destination mac in the dictionary but the
>>> problem is when f_id increases it then save same source and destination mac
>>> again and again.
>>> > What I want is to save mac address only if its not in dictionary.
>>>
>>>
>>
>>
>> --
>>
>>
>>
>>
>> *Regards Sayed Qaiser Ali ShahMSIT-12 NUST (SEECS)*
>>
>>
>>
>
>
> --
>
>
>
>
> *Regards Sayed Qaiser Ali ShahMSIT-12 NUST (SEECS)*
>
>
>


-- 




*RegardsSayed Qaiser Ali ShahMSIT-12NUST (SEECS)*
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