[nox-dev] The LLDP problem when using Extreme OpenFlow-enabled switch
Hi, Recently, we use the discovery and lavi applications in NOX. The experiment environment contains two different switches, one is PC w/ NetFPGA and the other is Extreme OpenFlow enabled-Switch. After starting the discovery app, we got the complaint messages on the console. The messages are showed below: 00103|pyrt|ERR:unable to invoke a Python event handler: Traceback (most recent call last): File ./nox/lib/util.py, line 116, in f event.total_len, buffer_id, packet) File ./nox/netapps/discovery/discovery.py, line 163, in lambda discovery.lldp_input_handler(self,dp,inport,reason,len,bid,packet), File ./nox/netapps/discovery/discovery.py, line 251, in lldp_input_handler assert (packet.type == ethernet.LLDP_TYPE) AssertionError After trying to debug these two days and check the ethernet frame, we print received packet and find some hints from discovery.py [(Extreme Networks):51:a9:8501:23:20:00:00:01:VLAN](vlanid=10: pcp=0)[LLDP]chassis ID:00:04:96:51:a9:85port ID:00:01ttl:120tlv end [(Nicira Network):a3:71:e301:23:20:00:00:01:LLDP]chassis ID:00:23:20:a3:71:e3port ID:00:02ttl:120tlv end The Extreme Switch will pack the VLAN info into the OFP packet, so we modify a little parts of ethernet.py. This code just skip the VLAN part (4 bytes) of ethernet frame. The attachment is our modified code. Although it works, we are not sure doing this is right or not. We are not the python expert and maybe you guys could provide better way for this. Thanks, Jen-Wei ethernet.patch Description: Binary data ___ nox-dev mailing list nox-dev@noxrepo.org http://noxrepo.org/mailman/listinfo/nox-dev
Re: [nox-dev] The LLDP problem when using Extreme OpenFlow-enabled switch
Hmm... I don't immediately know what the right thing to do in this situation is. But if it's to ignore the vlan (which doesn't immediately seem completely unreasonable), I think maybe the right approach is to replace that assert at the start of lldp_input_handler() with something like: if packet.type == ethernet.VLAN_TYPE: if not packet.next: lg.error(lldp_input_handler could not parse vlan frame) return packet = packet.next assert (packet.eth_type == ethernet.LLDP_TYPE) else: assert (packet.type == ethernet.LLDP_TYPE) That's 100% untested, so if you wanted to give it a try, please let me know how it turns out. :) Anyone want to comment on whether that's the right approach? -- Murphy On Thursday, May 26, 2011 01:47:00 AM Jen-Wei Hu wrote: Hi, Recently, we use the discovery and lavi applications in NOX. The experiment environment contains two different switches, one is PC w/ NetFPGA and the other is Extreme OpenFlow enabled-Switch. After starting the discovery app, we got the complaint messages on the console. The messages are showed below: 00103|pyrt|ERR:unable to invoke a Python event handler: Traceback (most recent call last): File ./nox/lib/util.py, line 116, in f event.total_len, buffer_id, packet) File ./nox/netapps/discovery/discovery.py, line 163, in lambda discovery.lldp_input_handler(self,dp,inport,reason,len,bid,packet), File ./nox/netapps/discovery/discovery.py, line 251, in lldp_input_handler assert (packet.type == ethernet.LLDP_TYPE) AssertionError After trying to debug these two days and check the ethernet frame, we print received packet and find some hints from discovery.py [(Extreme Networks):51:a9:8501:23:20:00:00:01:VLAN](vlanid=10: pcp=0)[LLDP]chassis ID:00:04:96:51:a9:85port ID:00:01ttl:120tlv end [(Nicira Network):a3:71:e301:23:20:00:00:01:LLDP]chassis ID:00:23:20:a3:71:e3port ID:00:02ttl:120tlv end The Extreme Switch will pack the VLAN info into the OFP packet, so we modify a little parts of ethernet.py. This code just skip the VLAN part (4 bytes) of ethernet frame. The attachment is our modified code. Although it works, we are not sure doing this is right or not. We are not the python expert and maybe you guys could provide better way for this. Thanks, Jen-Wei ___ nox-dev mailing list nox-dev@noxrepo.org http://noxrepo.org/mailman/listinfo/nox-dev
Re: [nox-dev] The LLDP problem when using Extreme OpenFlow-enabled switch
Hi, Thanks Murphy. It works and I also think your suggestion is a good way. And thank again for how to use of packet.next. I think this is useful when the packet also contains another ethernet type inside. Hope my thought is right. Jen-Wei On Thu, May 26, 2011 at 5:36 PM, Murphy McCauley jam...@nau.edu wrote: Hmm... I don't immediately know what the right thing to do in this situation is. But if it's to ignore the vlan (which doesn't immediately seem completely unreasonable), I think maybe the right approach is to replace that assert at the start of lldp_input_handler() with something like: if packet.type == ethernet.VLAN_TYPE: if not packet.next: lg.error(lldp_input_handler could not parse vlan frame) return packet = packet.next assert (packet.eth_type == ethernet.LLDP_TYPE) else: assert (packet.type == ethernet.LLDP_TYPE) That's 100% untested, so if you wanted to give it a try, please let me know how it turns out. :) Anyone want to comment on whether that's the right approach? -- Murphy On Thursday, May 26, 2011 01:47:00 AM Jen-Wei Hu wrote: Hi, Recently, we use the discovery and lavi applications in NOX. The experiment environment contains two different switches, one is PC w/ NetFPGA and the other is Extreme OpenFlow enabled-Switch. After starting the discovery app, we got the complaint messages on the console. The messages are showed below: 00103|pyrt|ERR:unable to invoke a Python event handler: Traceback (most recent call last): File ./nox/lib/util.py, line 116, in f event.total_len, buffer_id, packet) File ./nox/netapps/discovery/discovery.py, line 163, in lambda discovery.lldp_input_handler(self,dp,inport,reason,len,bid,packet), File ./nox/netapps/discovery/discovery.py, line 251, in lldp_input_handler assert (packet.type == ethernet.LLDP_TYPE) AssertionError After trying to debug these two days and check the ethernet frame, we print received packet and find some hints from discovery.py [(Extreme Networks):51:a9:8501:23:20:00:00:01:VLAN](vlanid=10: pcp=0)[LLDP]chassis ID:00:04:96:51:a9:85port ID:00:01ttl:120tlv end [(Nicira Network):a3:71:e301:23:20:00:00:01:LLDP]chassis ID:00:23:20:a3:71:e3port ID:00:02ttl:120tlv end The Extreme Switch will pack the VLAN info into the OFP packet, so we modify a little parts of ethernet.py. This code just skip the VLAN part (4 bytes) of ethernet frame. The attachment is our modified code. Although it works, we are not sure doing this is right or not. We are not the python expert and maybe you guys could provide better way for this. Thanks, Jen-Wei ___ nox-dev mailing list nox-dev@noxrepo.org http://noxrepo.org/mailman/listinfo/nox-dev
