3Com 3226, 3250 manual Spanning Tree, Roving Analysis Port

12SUPERSTACK® 3 SWITCH 3226 AND SWITCH 3250 SOFTWARE VERSION 1.02 RELEASE NOTES

default gateway setting to be lost. You should always check the IP address and route configuration when restoring the configuration on another unit.

IGMP

Disabling IGMP when there are hosts subscribing to multicast IP streams may prevent clients from subscribing to multicast IP groups. Hosts may be unable to re-subscribe to the same multicast IP group, for more than 5 minutes, or until the unit is re-booted.

Spanning Tree

■When connecting switches together, 3Com recommends that spanning tree fast start should be disabled on the interconnecting ports (it is enabled by default on all 10/100 ports and disabled by default on 10/100/1000 and SFP ports). This can be done using the Physical Interface > Ethernet > Setup command on the Web interface.

■When connecting switches together, if spanning tree fast start is not disabled on the interconnecting ports, any previously learned addresses on links that become blocked will not correctly age out until the aging time has passed. If the switch is power cycled then the device will learn the addresses correctly.

■You must enable spanning tree before making changes to spanning tree settings. If you try to change spanning tree settings while the protocol is

disabled the following error messages will be generated:

Failed to set forward-time

Failed to set hello-time

■When you enable spanning tree, all spanning tree settings are reset to their default values. If you want to use custom settings for spanning tree, you must configure spanning tree after enabling it.

Roving Analysis Port

■When the roving analysis port feature is activated the analyzer should see a copy of all packets sent and received by the mirror port. The switch does not currently mirror frames sent by the management CPU of the switch itself. The analyzer port will therefore be unable to show management traffic from the unit or protocol control packets such as RIP which are being sent out of the mirror port.

■While the analyzer port is active it still operates as a normal network port, allowing traffic to be switched to and from other network ports. You must be careful to differentiate traffic seen by the analyzer which is from the mirror port and other network traffic which may be being sent through the analyzer port.

■The traffic sent out of the analyzer port follows the VLAN membership setup for the analyzer port and not the mirror port. You must manually reconfigure the VLAN membership of the analyzer port to match the mirror port or you will not see the correct tagged / untagged packets on the analyzer.