Specifications
Table Of Contents
- Table of Contents
- Preface Template Formats
- Web-based (GUI) Configuration
- Configuration
- Device Information
- System Information
- Serial Port Settings
- IP Address Settings
- IPv6 Address Settings
- IPv6 Route Settings
- IPv6 Neighbor Settings
- Port Configuration Folder
- Static ARP Settings
- User Accounts
- System Log Configuration Folder
- DHCP Relay Folder
- MAC Address Aging Time
- Web Settings
- Telnet Settings
- CLI Paging Settings
- Firmware Information
- SNTP Settings Folder
- SMTP Settings Folder
- SNMP Settings Folder
- Layer 2 Features
- Jumbo Frame
- VLANs
- 802.1Q Static VLAN
- Q-in-Q Folder
- 802.1v Protocol VLAN Folder
- GVRP Settings
- Asymmetric VLAN Settings
- MAC-based VLAN Settings
- PVID Auto Assign Settings
- Port Trunking
- LACP Port Settings
- Traffic Segmentation
- IGMP Snooping Folder
- MLD Snooping Settings
- Port Mirror
- Loopback Detection Settings Page
- Spanning Tree Folder
- Forwarding & Filtering Folder
- LLDP Folder
- Quality of Service (QoS)
- Security
- Access Control List (ACL)
- Monitoring
- Save and Tools
- System Log Entries
- Trap List
VLANs
Extreme Networks EAS 100-24t Switch Software Manual
49
● Untagging - The act of stripping 802.1Q VLAN information out of the packet header.
● Ingress port - A port on a switch where packets are flowing into the Switch and VLAN decisions
must be made.
● Egress port - A port on a switch where packets are flowing out of the Switch, either to another
switch or to an end station, and tagging decisions must be made.
IEEE 802.1Q (tagged) VLANs are implemented on the Switch. 802.1Q VLANs require tagging, which
enables them to span the entire network (assuming all switches on the network are IEEE 802.1Q-
compliant).
VLANs allow a network to be segmented in order to reduce the size of broadcast domains. All packets
entering a VLAN will only be forwarded to the stations (over IEEE 802.1Q enabled switches) that are
members of that VLAN, and this includes broadcast, multicast and unicast packets from unknown
sources.
VLANs can also provide a level of security to your network. IEEE 802.1Q VLANs will only deliver
packets between stations that are members of the VLAN.
Any port can be configured as either tagging or untagging. The untagging feature of IEEE 802.1Q
VLANs allows VLANs to work with legacy switches that don't recognize VLAN tags in packet headers.
The tagging feature allows VLANs to span multiple 802.1Q-compliant switches through a single
physical connection and allows Spanning Tree to be enabled on all ports and work normally.
The IEEE 802.1Q standard restricts the forwarding of untagged packets to the VLAN of which the
receiving port is a member.
802.1Q VLAN Tags
The figure below shows the 802.1Q VLAN tag. There are four additional octets inserted after the source
MAC address. Their presence is indicated by a value of 0x8100 in the EtherType field. When a packet's
The main characteristics of IEEE 802.1Q are as
follows:
● Assigns packets to VLANs by filtering.
● Assumes the presence of a single global
spanning tree.
● Uses an explicit tagging scheme with one-
level tagging.
● 802.1Q VLAN Packet Forwarding
● Packet forwarding decisions are made based
upon the following three types of rules:
● Ingress rules - rules relevant to the
classification of received frames belonging to
a VLAN.
● Forwarding rules between ports - decides
whether to filter or forward the packet.
● Egress rules - determines if the packet must
be sent tagged or untagged.