Summer 2017, Corboy 205, TTh 5:30-8:45 pm
Class 7: July 25
Midterm study guide (solutions are on
There are two broad approaches to eliminating loops in a network:
- discover the topology, and then build a spanning tree
- take advantage of what is known of the topology to set up loopless
We already saw the second approach in switchring.py
Interconnection fabric: intronetworks.cs.luc.edu/current/html/ethernet.html#openflow-switches.
3. Continuation with trunkNK.py and multitrunkpox.py
TCP connections take trunk 1, 2, or 3, in sequence.
trunkNK.py: setting link bandwidths
multitrunkpox.py: assign new TCP connections to one of the trunks, in
round-robin fashion via picktrunk().
Note that this requires matching on the IP
addresses and TCP ports, as well as the Ethernet addresses.
- ConnectionUp events
- PacketIn events
- TCP connections: finding a path, creating OpenFlow rule
Continuation with SNMP
Other ways of polling devices:
ssh: limitations: lack of "universal" account
for most hubs/switches/non-hosts