Cabletron Systems SmartSTACK ELS10-27TX Supplement Manual

Contents

1-6Introduction1.3.5 Switch ModeThe unit operates in either an 802.1D or 802.1Q mode. The mode must beselected by the user and applies to all ports. The unit will not operate in a mixedmode. The default is to operate in 802.1D mode.For further information, refer to Switch Command in Chapter 2, Enhancements toLCM Commands.1.3.6 Assigning Ports to a VLANA port becomes a member of a VLAN, by using the VLAN command.For further information, refer to the Port Command in Chapter 2, Enhancementsto LCM Commands.1.3.7 Default Port VLAN IDIf the unit is operating in 802.1Q mode, then each port will be configured with adefault port VLAN ID (PVID). The default value for each port will be the defaultVLAN ID of 0x001. You are allowed to modify this on a per port basis.When 802.1Q was developed, it was decided to configure a default VLAN ID fora port. If a packet is received on a port that does not have a VLAN ID or does nothave a VLAN ID of zero, the default VLAN ID will be inserted. Once this tag isin place the packet is sent to the forwarding engine. Once the forwarding enginereceives it, it will use this tag to determine which VLAN to restrict this packet to.The sub-command of the port command known as the VLAN sub-command isused to set the default VLAN ID for the port.For further information, refer to Port Command in Chapter 2, Enhancements toLCM Commands.NOTE There is a sub-command of the port command known as theVLAN sub-command. This is not used to make a port a memberof the VLAN, and is not directly used in the forwarding andfiltering decision.