[pox-dev] no route to host - loop topology

[Murphy McCauley]

(Inline.)

On Dec 25, 2013, at 1:51 AM, Silvia Fichera <fichera.sil at gmail.com> wrote:

> I've tried with l2_learning and the result it's the same:
> 
> ERROR:openflow.of_01:[00-00-00-00-00-02 3] OpenFlow Error:
> [00-00-00-00-00-02 3] Error: header: 
> [00-00-00-00-00-02 3] Error:   version: 1
> [00-00-00-00-00-02 3] Error:   type:    1 (OFPT_ERROR)
> [00-00-00-00-00-02 3] Error:   length:  76
> [00-00-00-00-00-02 3] Error:   xid:     8997
> [00-00-00-00-00-02 3] Error: type: OFPET_BAD_REQUEST (1)
> [00-00-00-00-00-02 3] Error: code: OFPBRC_BUFFER_UNKNOWN (8)
> [00-00-00-00-00-02 3] Error: datalen: 64
> [00-00-00-00-00-02 3] Error: 0000: 01 0e 00 50 00 00 23 25  00 00 00 00 00 11 26 02   |...P..#%......&.|
> [00-00-00-00-00-02 3] Error: 0010: f7 19 00 cf 26 c6 2c c9  90 93 ff ff 00 00 08 00   |....&.,.........|
> [00-00-00-00-00-02 3] Error: 0020: 00 06 00 00 0a 54 37 f2  0a 00 00 65 b3 51 13 89   |.....T7....e.Q..|
> [00-00-00-00-00-02 3] Error: 0030: 00 00 00 00 00 00 00 00  00 00 00 0a 00 1e 80 00   |................|
> 
> 
> What do you exactly mean with manually down?

Mininet has commands to set a link up or down via its CLI.  You might manually take them down, start raising them in a non-loop way, testing that things work, and then see if things immediately break when upping one that loops.  Something like that.

> I've tried with no loop topology and it works fine except when, while mininet starts switches, it says this (None 2, in this case):
> 
> NFO:core:POX 0.2.0 (carp) is up.
> INFO:openflow.of_01:[8e-a0-3f-85-d5-41 1] connected
> INFO:packet:(dhcp parse) warning DHCP packet data too short to parse header: data len 86
> INFO:openflow.of_01:[None 2] disconnected
> INFO:openflow.of_01:[None 2] closed
> INFO:openflow.of_01:[00-00-00-00-00-01 3] connected
> INFO:openflow.of_01:[00-00-00-00-00-02 4] connected
> INFO:openflow.of_01:[00-00-00-00-00-03 5] connected
> INFO:openflow.of_01:[00-00-00-00-00-04 6] connected
> INFO:openflow.of_01:[00-00-00-00-00-05 7] connected
> INFO:openflow.of_01:[00-00-00-00-00-06 8] connected
> INFO:openflow.discovery:link detected: 8e-a0-3f-85-d5-41.1 -> 00-00-00-00-00-04.1
> INFO:openflow.of_01:[00-00-00-00-00-07 9] connected
> INFO:openflow.of_01:[00-00-00-00-00-08 10] connected
> INFO:openflow.of_01:[00-00-00-00-00-09 11] connected

You've got a packet very early on (the DHCP packet).  Do you know where it's coming from?

Can you check that all your switches are defaulting to fail-secure and not fail-standalone?

I am wondering if somehow you're still getting a loop.  Are you getting lots of the BUFFER_UNKNOWN errors?  Can you sniff traffic in the Mininet network and check if there's just a ton?

Can you describe your configuration?  Are you using FlowVisor?  Running software in the Mininet hosts?

-- Murphy

> Thanks!
> 
> 
> 
> 
> 2013/12/24 Murphy McCauley <murphy.mccauley at gmail.com>
> Hmm...  I wonder if you're getting a loop anyway.
> 
> As a first test, what happens if you try using l2_learning instead of l3_learning?
> 
> What if you manually down links to remove loops?
> 
> -- Murphy
> 
> On Dec 24, 2013, at 10:42 AM, Silvia Fichera <fichera.sil at gmail.com> wrote:
> 
> > Hi all,
> > I have a topology with loops, and my version of Pox is up-to-date.
> > I run pox in this way:
> >
> > ./pox.py forwarding.l3_learning openflow.discovery --eat-early-packets openflow.spanning_tree --no-flood --hold-down
> >
> > after running pox I start mininet and I try to build a tcp connection with iperf from 2 hosts to the same host.
> > But I can't reach it (no route to host) and I have this error:
> >
> > ERROR:openflow.of_01:[00-00-00-00-00-02 5] OpenFlow Error:
> > [00-00-00-00-00-02 5] Error: header:
> > [00-00-00-00-00-02 5] Error:   version: 1
> > [00-00-00-00-00-02 5] Error:   type:    1 (OFPT_ERROR)
> > [00-00-00-00-00-02 5] Error:   length:  76
> > [00-00-00-00-00-02 5] Error:   xid:     2046
> > [00-00-00-00-00-02 5] Error: type: OFPET_BAD_REQUEST (1)
> > [00-00-00-00-00-02 5] Error: code: OFPBRC_BUFFER_UNKNOWN (8)
> > [00-00-00-00-00-02 5] Error: datalen: 64
> > [00-00-00-00-00-02 5] Error: 0000: 01 0e 00 48 00 00 07 fe  00 00 20 40 00 18 d2 87   |...H...... @....|
> > [00-00-00-00-00-02 5] Error: 0010: 03 64 03 d1 00 00 00 00  00 06 ff ff 00 00 08 00   |.d..............|
> > [00-00-00-00-00-02 5] Error: 0020: 00 06 00 00 00 00 00 00  0a 00 00 65 00 00 13 89   |...........e....|
> > [00-00-00-00-00-02 5] Error: 0030: 00 00 00 00 00 00 00 00  00 00 00 00 00 00 80 00   |................|
> >
> > Sometimes it happens just for one of the sender, sometimes for both of them.
> > Do you know how can I solve it?
> >
> > Thank you and Happy Xmas
> >
> > --
> > Silvia Fichera
> 
> 
> 
> 
> -- 
> Silvia Fichera

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