Enterasys Networks ELS10-27TX manual Ieee 802.1Q Standard

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Introduction

1.2.1 IEEE 802.1Q Standard

IEEE 802.1Q is a standard for virtual bridged local area networks (VLANs). It provides an alternate method for forwarding packets through a switch. In an 802.1D (Spanning Tree) bridge, packets are forwarded in accordance with the spanning tree as dynamically created by the 802.1D protocol (Bridge Protocol Data Units [BPDUs]), and the spanning tree state of each port. In 802.1Q, in addition to spanning tree, packets are forwarded in accordance with a VLAN tag that is embedded in the packet, and the set of ports registered for that VLAN. A set of rules is used for ingress (receipt), forwarding, and egress (transmit).

The SmartSTACK Ethernet ELS10-27TX provides support for port based VLANs.

The ingress rules deal with the reception of tagged and untagged packets and the decision to either drop them, or forward them to the forwarding process.

The forwarding rules deal with forwarding packets using topology restrictions, the filtering database, queue frames (not supported), map priorities (not supported), and recalculation of the FCS. The forward/filtering database can contain three types of entries:

•Permanent entries

•Static entries

•Dynamic entries

Dynamic entries are created using the protocols supported by the switch (GVRP). There will be no learning of VLANs outside of this protocol.

NOTE

There is no support for GVRP with ELS10-27TX Version 1.01.00. GVRP will be supported in a subsequent release.

The egress rules deal with whether the destination port(s) are members of the VLAN, and whether the VLAN tag is to be stripped. There is also an issue of address translation on a packet that is having the VLAN tag stripped. This only applies to multi-protocol environments, such as a combination of Ethernet, FDDI, and Token Ring protocols and does not apply to the SmartSTACK Ethernet ELS10-27TX.

The 802.1Q standard does not replace 802.1D. It limits the relaying of packets on the spanning tree to a subset: the subset being the members of a particular VLAN. This is determined by comparing the VLAN ID, which is a field within the tag, to the ports which are members of that VLAN.

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Contents SmartSTACK Ethernet ELS10-27TX Supplement Page Page FCC Notice Cabletron SYSTEMS, INC Program License Agreement Page Page Page Cabletron Systems Limited Program License Agreement Viii Page Declaration of Conformity Contents Configuring Vlans Using Snmp Vlan MIB ObjectsXiii Workgroup MIB Objects Configuring Workgroups Using LCMConfiguring Workgroups Using Snmp Appendix a Virtual Lans Vlans IndexAbout this Supplement Getting Help Your email addressDocument Conventions Related Documentation Document Title Part NumberUsing Vlans on the ELS10-27TX Product OverviewIeee 802.1Q Standard Vlan Hybrid Ports 802.1Q Mode 802.1Q Mode on ELS10-27TXVlan Access Ports 802.1Q Mode 3 802.1Q Trunk Ports Preserving PriorityAccessing Network Management Using VLANs Non-Preserving PriorityDefault Port Vlan ID Switch ModeAssigning Ports to a Vlan Restricting VLANs 802.1Q Mode Enable GvrpVirtual Workgroups will only operate in 802.1D mode WorkgroupsDefault Gateway Installation and ManagementPage Overview LCM ConventionsLCM Command Summary Subset of LCM CommandsLCM Command Syntax Erase Basic LCM CommandsHelp Exit or LogoutLCM Commands Enable Command Address LimitRoute Command Port Command Port CommandEnhancements to LCM Commands Switch Command Trap Control Command Vlan Command ELS10-27vlan add 5-9 bluePage Configuring Vlans Using Snmp Overview Config TableStep Action Modifying, Creating and Deleting VLANsModifying a Vlan Creating a Vlan Deleting a VlanConfig Egress List Modifying a Config Egress List Entry Filter Gvrp Table Modifying, Creating or Deleting a Filter Gvrp Table EntryCreating a Filter Deleting a FilterCreating a Static MAC Entry Static MAC EntryDeleting a Static MAC Entry Bridge Configuration Vlan Version NumberOperating Mode VlanOperatingMode Reset VlanResetGvrp Enable VlanGVRPEnable Syntax Octet String SizeAccess List VlanAccessList Vlan VlanConfigVlanEntry VlanConfigEntry Configuration EntriesVlanConfigEntry Index VlanConfigIndex VID VlanConfigVIDPorts VlanConfigPorts IP VlanConfigIPIP Mask VlanConfigIPMask Name VlanConfigNameStatus VlanConfigStatus Establish VlanConfigEstablishDevice Entries Static Configured VlanNumConfiguredEntriesActive VlanNumActiveEntries Configuration Table VlanConfigTable Maximum Number VlanMaxNumEntriesEgress Table Egress Table VlanConfigEgressTable Egress Entry VlanConfigEgressEntryVlanConfigEgressEntry Index VlanEgressIndexVID VlanEgressVID List VlanEgressListStatus VlanEgressStatus Gvrp VlanFilterGVRPTable Filter GvrpEntry VlanFilterGVRPEntry VlanFilterGVRPIndex VlanFilterGVRPEntryVID VlanFilterGVRPVID List VlanFilterGVRPListStatus VlanFilterGVRPStatus EstablishVID VlanFilterGVRPEstablishVIDTable VlanStaticTable Static MAC Address EntriesEntry VlanStaticEntry VID VlanStaticVID VlanStaticEntryMAC VlanStaticMAC Port VlanStaticPortEstablish VlanStaticEstablish Page Chapter Configuring Workgroups Using LCM Overview Workgroup Configuration Examples Workgroup DefaultWorkgroup Superset LCM Workgroup Commands Workgroups are only valid in 802.1D modeELS10-27workgroup omega Page Chapter Configuring Workgroups Using Snmp Overview Workgroup Configuration Procedures Configuring Workgroups Using Snmp Page Chapter Workgroup MIB Objects Overview Workgroups Using SnmpNext Number WorkGroupNextNumber Current Count WorkGroupCurrentCount MAX Count WorkGroupMaxCountTable WorkGroupTable Entry WorkGroupEntry Number WorkGroupNumber Name WorkGroupNamePorts WorkGroupPorts Type WorkGroupTypeAppendix a Virtual Lans Vlans Vlans and Frame Tagging Vlan Vlan YELS10-27TX Vlan Configuration Vlan IDPorts in Vlan Vlan Access PortsVlan Egress Figure A-2. Vlan Access Ports Index NumericsSnmp Index