The followings are NOX debug information when a host joins in. (its IP address
is set to 192.168.1.16 and MAC address is c8:60:00:b9:c1:50 ).
00090|openflow-event|DBG:received packet-in event from 001bcd03006c (len:82)
00091|authenticator|DBG:Automatically authing c8:60:00:b9:c1:50 192.168.1.16.
00092|authenticator|DBG:Binding for host doesnt exist, using default.
00093|authenticator|DBG:Host auth event received.
00094|authenticator|DBG:authenticated added location authenticated to
c8:60:00:b9:c1:50.
00095|authenticator|DBG:Added c8:60:00:b9:c1:50 192.168.1.16 to host
authenticated.
00096|sp_routing|DBG:Broadcasting 1bcd03006c port0002:vlanffff:pcp:0
macc8:60:00:b9:c1:50->ff:ff:ff:ff:ff:ff proto0800
ip192.168.1.16->255.255.255.255 port3601->3600
.....
I think the host must report its information to NOX in some way. Then the
topology or host table(maintain in NOX) will update, and if there is no route
calculated by routing component according to topology information, it means no
path existed. So no need to flood.
Well, maybe i make a misunderstanding in some places, please help me.
Wang JIan
2012-7-24
At 2012-07-24 13:49:12,"Murphy McCauley" <[email protected]> wrote:
(Hah, looks like maybe my mobile had a misfire there.)
I'm not sure what information you think the host is sending when it joins,
but... a host is not required to send anything. It may send stuff. Hosts
often do. But there's no host-joining-a-network protocol or anything.
NOX learns about a host's presence whenever that host sends *anything*. But if
a host is quiet, NOX will never learn about it. Thus, it can easily be the
case that a host is on the network and NOX has no idea. Thus, if someone wants
to send to that host... NOX has no idea where it should be sending it. The two
main options at this point would be: A) Drop (because you don't know where the
destination is, or even if it exists at all), or B) Flood (which, if the
destination exists, will definitely get the packet there).
-- Murphy
On Jul 23, 2012, at 7:37 PM, 王健 wrote:
But a host reports its own information when joins in the network, which I
observe according to NOX debug information. Does the topology will be updated?
If not, how does it update? Thank you very much.
在 2012-07-24 10:23:39，"Murphy McCauley" <[email protected]> 写道：
On Jul 23, 2012, at 7:19 PM, 王健 wrote:
Thank Murphy and Kyriakos for your patient reply, i am sorry that maybe i don't
express my meaning clearly. When a host joins in the network, it receives the
peridictly LLPP packet and reply its own information such as IP, MAC, access
point to the NOX. Then the NOX update the topology immediately when it receives
the host join in event, isn't it? If the toology is update immediately, then
there is a quetion I can't think clealy. If host A sends an ICMP request to
host B, the path_calculation_module says there is no route, it means there is
no path between A and B, isn't it? If so, I think there is no need to
broadcast. This confuses me a lot. I think maybe I was wrong somewhere, can you
help me?
I think you're saying that you expect the hosts to be receiving the LLDP from
the switch and then responding. This isn't the case. The hosts are not
expected to participate in the LLDP conversation -- it is strictly between
switches.
-- Murphy
