HP 6208M-SX - Manual (Page 5)

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When multiple-instance STP is enabled, if VLAN 100 uses STP and VLAN 101 does not, the configuration file generated
by
show config shows the following:
For more information on STP, see "Default Spanning Tree Protocol (STP) Settings" on page 3.
Implementing Spanning Tree Protocol (STP) in a Tagged VLAN Environment
Condition. The HP ProCurve 9304M, 9308M, and 6308M-SX routing switches and the 6208M-SX switch offer both
multiple-instance and single-instance spanning tree. The HP ProCurve 1600M, 2400M, 2424M, 4000M, and 8000M
switches use single-instance spanning tree only. In a network where multiple-instance STP is configured on a 9304M,
9308M, 6308M-SX, or 6208M-SX, STP will fail on a connection between any of these devices and a single-instance STP
device if the STP Priority parameter settings are left at their defaults. (In most cases, the 6308M-SX and 6208M-SX
would be used in the core network, and would not be configured for multiple-instance STP.) That is, if one or more
of the single-instance STP-enabled switches in the network uses the default STP
Priority parameter setting (32768),
then one of these switches will become the root bridge (due the MAC addresses in these switches being lower than
the MAC addresses in the multiple-instance STP devices). When this occurs, STP fails on any links between the (root
bridge) switch and any multiple-instance STP device (9304M, 9308M, 6308M-SX, or 6208M-SX) to which the switch
is connected.
Solution. Interoperability testing indicates that the STP configuration allows for proper interoperation between a
9304M, 9308M, 6308M-SX, or 6208M-SX (configured for multiple-instance STP) and a 1600M, 2400M, 2424M, 4000M,
or 8000M switch in a tagged VLAN environment.
1. On the 9304M, 9308M, 6308M-SX, or 6208M-SX, ensure that software release 05.2.14 or later is installed.(This
release is included with devices shipped after 10/01/99, and is also available in the Support area of HP’s ProCurve
website at
http://www.hp.com/go/procurve).
2. Disconnect the 9304M, 9308M, 6308M-SX, or 6208M-SX from all 1600M, 2400M, 2424M, 4000M, and 8000M
switches.
3. Configure the 9304M, 9308M, 6308M-SX, or 6208M-SX to be the root bridge. Do this by changing the STP Priority
parameter to a value that is lower than the default setting of 32768. (This assumes that the STP Priority parameter
in the 1600M, 2400M, 2424M, 4000M, and 8000M switch(es) is either set at the default or is set to a higher value
than the
Priority setting you are using in the 9304M, 9308M, 6308M-SX, or 6208M-SX.)
ver 05.2.1x
!
global-stp
!
vlan 100 by port
tagged ethe 3/1 to 3/2
span
!
vlan 101 by port
tagged ethe 3/1 to 3/2 Shows the software version for the device.
Indicats that multiple-instance STP is enabled on the device.
In the case of multiple-instance STP, the VLAN(s) on which STP is running are
indicated by the presence of span.
9308M
Routing Switch
STP enabled
(multiple instance)
Switch 8000M
STP enabled
(single instance)
For STP to operate properly in this example, the
9308M STP Priority parameter must be lower
than the Priority parameter setting in the Switch
8000Ms. (See "Solution", below.)
Switch 8000M
STP enabled
(single instance)