At IU, is my Ethernet switch compatible with the campus network?
On this page:
- Requirements for end-user switches
- Testing end-user switches
Ethernet hubs, repeaters, and switches are a cost-effective way to provide network connectivity to multiple devices via a single data jack. However, improperly implemented switches can result in network problems for an entire building or even, in some rare cases, an entire campus. To prevent network problems, end-user Ethernet switches on the Indiana University network must meet the basic requirements published by UITS.
For the purposes of this document, an end-user switch is any Ethernet switch, hub, or repeater connected to a UITS data jack.
Requirements for end-user switches
UITS has established the following set of requirements for end-user switches. For a list of end-user switches that have been found to meet these requirements, see At IU, what switches are recommended for use on the campus network?
- End-user switches must support one of the following:
- A functional IEEE standard spanning tree implementation (802.1d, 802.1w, or 802.1s)
- Flooding of all IEEE standard spanning tree BPDU frames to all ports on the switch
- End-user switches must not implement Cisco's proprietary PVST
spanning tree protocols.
- End-user switches must not implement IGMP snooping.
- End-user switches must not allow the user to alter the
configuration or behavior of the switch in any way; only unmanaged
switches are allowed.
- End-user switches must support the same functionality on all ports. No dedicated uplink ports are allowed.
Testing end-user switches
Use the following set of testing procedures to confirm that switches comply with the UITS end-user switch requirements:
Testing for spanning tree compatibility
- Power on the switch and connect a single PC to the switch. Do not
connect the switch to the data jack, other switches, or other PCs.
- Start a packet capture on the PC and look for
spanning tree packets. Run the packet capture for at least 30
- IEEE spanning tree packets are sent to the MAC
spanning tree packets are sent to the MAC address
- IEEE spanning tree packets are sent to the MAC address
- If you detect IEEE spanning tree packets, the switch
runs spanning tree and passes the test. If you detect Cisco
spanning tree packets, the switch fails the test. If you do not
detect any kind of spanning tree packets, proceed to step 4.
- Connect the PC directly to a data jack and repeat the packet
capture from step 2. If you do not detect IEEE spanning tree
packets, you cannot use this data jack for testing an end-user
switch. If you do detect IEEE spanning tree packets, continue to
- Connect the PC to the end-user switch, and then connect the switch to the data jack. Repeat the test from step 2. If you detect IEEE spanning tree packets, the switch floods spanning tree packets and passes the test. If you do not detect spanning tree packets, this switch fails the test and cannot be used.
Testing for IGMP snooping compatibility
For this test, you will need an application to test multicast streams, such as VLC media player. VLC player is a free application for Windows, Mac OS X, and Linux operating systems, and is available for download at the Videolan web site. To open a multicast stream with VLC player:
File, and then click
Open Network Stream...(Windows) or
Open Network...(Mac OS X).
- In the
Open Source(Mac OS X) window, select
- Enter the address and port of the multicast stream in the
appropriate fields, and then click
OKto open the stream. There may be a slight delay before the stream begins to play.
To test for IGMP snooping compatibility:
- Connect a PC to the data jack you plan to use for testing. Run a
multicast application on the PC. Open a multicast stream, and
verify that it works. Note the multicast group address of the
Note: From the IU network, you can use a sample multicast stream for this test; this sample stream address is
- Connect the PC to the switch being tested, connect the switch to
the data jack tested in step 1, and connect a second PC with
packet-sniffing software installed to the switch.
- Restart the multicast stream tested in step 1, and verify it is
- Start a packet capture on the second PC, and run for at least 15
- Check the packet capture for UDP packets with a destination of the multicast group address noted in step 1. There should be a lot of them! If you do not detect multicast packets, the switch implements IGMP snooping and therefore fails the test. If you do detect these multicast packets, the switch passes.
Last modified on October 17, 2013.