User`s guide
Table Of Contents
- Title
- Notice
- Contents
- Figures
- Tables
- About This Guide
- Introduction
- Local Management Requirements
- Accessing Local Management
- 3.1 Navigating Local Management Screens
- 3.2 Password Screen
- 3.3 Main Menu Screen
- 3.4 Module Selection Screen
- 3.5 Module Menu Screen
- 3.6 Overview of Security Methods
- 3.7 Security Menu Screen
- 3.8 Passwords Screen
- 3.9 Radius Configuration Screen
- 3.10 Name Services Configuration Screen
- 3.11 System Authentication Configuration Screen
- 3.12 EAP (Port) Configuration Screen
- 3.13 EAP Statistics Menu Screen
- 3.14 MAC Port Configuration Screen
- 3.15 MAC Supplicant Configuration Screen
- Chassis Menu Screens
- 4.1 Chassis Menu Screen
- 4.2 Chassis Configuration Screen
- 4.3 SNMP Configuration Menu Screen
- 4.4 SNMP Community Names Configuration Screen
- 4.5 SNMP Traps Configuration Screen
- 4.6 Chassis Environmental Information Screen
- 4.7 Redirect Configuration Menu Screen (Chassis)
- 4.8 Port Redirect Configuration Screen
- 4.9 VLAN Redirect Configuration Screen
- Module Configuration Menu Screens
- 5.1 Module Configuration Menu Screen
- 5.2 General Configuration Screen
- 5.2.1 Setting the IP Address
- 5.2.2 Setting the Subnet Mask
- 5.2.3 Setting the Default Gateway
- 5.2.4 Setting the TFTP Gateway IP Address
- 5.2.5 Setting the Module Name
- 5.2.6 Setting the Module Date
- 5.2.7 Setting the Module Time
- 5.2.8 Entering a New Screen Refresh Time
- 5.2.9 Setting the Screen Lockout Time
- 5.2.10 Configuring the COM Port
- 5.2.11 Clearing NVRAM
- 5.2.12 Enabling/Disabling IP Fragmentation
- 5.3 SNMP Configuration Menu Screen
- 5.4 SNMP Community Names Configuration Screen
- 5.5 SNMP Traps Configuration Screen
- 5.6 Access Control List Screen
- 5.7 System Resources Information Screen
- 5.8 FLASH Download Configuration Screen
- Port Configuration Menu Screens
- 6.1 Port Configuration Menu Screen
- 6.2 Ethernet Interface Configuration Screen
- 6.3 Ethernet Port Configuration Screen
- 6.4 HSIM/VHSIM Configuration Screen
- 6.5 Redirect Configuration Menu Screen
- 6.6 Port Redirect Configuration Screen
- 6.7 VLAN Redirect Configuration Screen
- 6.8 Link Aggregation Screen (802.3ad Main Menu Screen)
- 6.9 Broadcast Suppression Configuration Screen
- 802.1 Configuration Menu Screens
- 802.1Q VLAN Configuration Menu Screens
- 8.1 Summary of VLAN Local Management
- 8.2 802.1Q VLAN Configuration Menu Screen
- 8.3 Static VLAN Configuration Screen
- 8.4 Static VLAN Egress Configuration Screen
- 8.5 Current VLAN Configuration Screen
- 8.6 Current VLAN Egress Configuration Screen
- 8.7 VLAN Port Configuration Screen
- 8.8 VLAN Classification Configuration Screen
- 8.9 Protocol Port Configuration Screen
- 802.1p Configuration Menu Screens
- 9.1 802.1p Configuration Menu Screen
- 9.2 Port Priority Configuration Screen
- 9.3 Traffic Class Information Screen
- 9.4 Traffic Class Configuration Screen
- 9.5 Transmit Queues Configuration Screen
- 9.6 Priority Classification Configuration Screen
- 9.7 Protocol Port Configuration Screen
- 9.8 Rate Limiting Configuration Screen
- Layer 3 Extensions Menu Screens
- Module Statistics Menu Screens
- Network Tools Screens
- VLAN Operation and Network Applications
- 13.1 Defining VLANs
- 13.2 Types of VLANs
- 13.3 Benefits and Restrictions
- 13.4 VLAN Terms
- 13.5 VLAN Operation
- 13.6 Configuration Process
- 13.7 VLAN Switch Operation
- 13.8 VLAN Configuration
- 13.9 Summary of VLAN Local Management
- 13.10 Quick VLAN Walkthrough
- 13.11 Examples
- 13.12 Example 1, Single Switch Operation
- 13.13 Example 2, VLANs Across Multiple Switches
- 13.14 Example 3, Filtering Traffic According to a Layer 4 Classification Rule
- 13.15 Example 4, Securing Sensitive Information According to Subnet
- 13.16 Example 5, Using Dynamic Egress to Control Traffic
- 13.17 Example 6, Locking a MAC Address to a Port Using Classification Rules
- Generic Attribute Registration Protocol (GARP)
- About IGMP
- Index

VLAN Switch Operation
13-10 VLAN Operation and Network Applications
13.7.1 Receiving Frames from VLAN Ports
When a switch is placed in 802.1Q Operational Mode, every frame received by the switch must
belong, or be assigned, to a VLAN.
The switch will now make a forwarding decision on the frame, as described in Section 13.7.2.
Untagged Frames
The switch receives a frame from Port 1 and examines the frame. The switch notices that this
frame does not currently have a VLAN tag. The switch recognizes that Port 1 is a member of
VLAN A and classifies the frame as such. In this fashion, all untagged frames entering a VLAN
switch assume membership in a VLAN.
The switch will now make a forwarding decision on the frame, as described in Section 13.7.2.
Tagged Frames
In this example, the switch receives a tagged frame from Port 4. The switch examines the frame
and notices the frame is tagged for VLAN C. This frame may have already been through a
VLAN-aware switch, or originated from a station capable of specifying a VLAN membership. If a
switch receives a frame containing a tag, the switch will classify the frame in regard to its tag
rather than the PVID for its port.
The switch will now make a forwarding decision on the frame, as described in Section 13.7.2.
13.7.2 Forwarding Decisions
The type of frame under consideration and the filter setting of a VLAN switch determines how the
switch forwards VLAN frames.
13.7.2.1 Broadcasts, Multicasts, and Unknown Unicasts
If a frame with a broadcast, multicast, or other unknown address is received by an 802.1Q
VLAN-aware switch, the switch checks the VLAN classification of the frame. The switch then
forwards the frame out all ports that are identified in the Egress List for that VLAN. For example,
if Port 3, shown in Figure 13-2, received the frame, the frame would then be sent to all ports that
had VLAN C in their Port VLAN List.
NOTE: A VLAN ID is always assigned to a port. By default, it is the Default VLAN
(VLAN ID = 1).