Hi all!
I need to calculate the bandwidth and latency between two switches. To
achieve this, I plan to:
C
___|___
/ \
/ \
h1------p1:s1:p2-----p1:s2:p2--------h2
-bandwidth:
1. stat0 = number of packets that went through s1_p1 and s2_port1 at
time t1
2. generate traffic from s1 to s2
3. stat1 = number of packets that went through s1_p1 and s2_port1 at
time t2
4. bandwidth = (stat1-stat0)*size_of_packet/(t2-t1)
-latency:
1. latency = send a packet from s1 to s2, check the timestamp at s1,
s2, subtract them
However, I am having trouble as to generating traffic. I checked the stats *
variable* passed to the datapath_join events, and i get the following:
{'ports': [
>
> {'hw_addr': 'b\x9e\x04\xb9h,', 'curr': 192, 'name': 's1-eth2', 'speed':
>> 10000, 'supported': 0, 'enabled': True, 'flood': True, 'state': 0, 'link':
>> True, 'advertised': 0, 'peer': 0, 'config': 0, 'port_no': 2}, {'hw_addr':
>> '\x00# \xba\xc0\x97', 'curr': 0, 'name': 'dp0', 'speed': 0, 'supported':
>> 0, 'enabled': False, 'flood': True, 'state': 1, 'link': False,
>> 'advertised': 0, 'peer': 0, 'config': 1, 'port_no': 65534}, {'hw_addr':
>> '\x9e\xe7\xf1\xcb\xdd\x17', 'curr': 192, 'name': 's1-eth1', 'speed':
>> 10000, 'supported': 0, 'enabled': True, 'flood': True, 'state': 0, 'link':
>> True, 'advertised': 0, 'peer': 0, 'config': 0, 'port_no': 1}], 'n_tables':
>> 2, 'n_bufs': 256L, 'actions': 4095L, 'caps': 135L}
>
>
I've been looking into these stats (and switchstats as well) for a while,
because I believe they can help me retrieve the information I need.
However, I am unsure as to what '*speed*' here means. Also, I can't see
where the number of packets that traverse a port is.
Openflow does maintain counters for each flow table, and these counters
have the number of received packets per port, etc... How can I retrieve
these?
Thank you in advance!
Best regards
Meilleures Salutations,
Walid van Boetzelaer
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