Dell PowerEdge VRTX - Manual (Page 312)

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FILE LOCATION: C:\Users\gina\Desktop\Checkout_new\Dell Plasma\User
Guide\Plasma_UGSwitching_VLAN.fm
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bridging domain. The bridging domain is supported on various pieces of
network equipment; for example, LAN switches that operate bridging
protocols between them with a separate bridge group for each VLAN.
VLANs are created to provide the segmentation services traditionally
provided by routers in LAN configurations. VLANs address scalability,
security, and network management. Routers in VLAN topologies provide
broadcast filtering, security, address summarization, and traffic flow
management.
None of the switches, within a defined group, will bridge any frames, not even
broadcast frames, between two VLANs.
Frame Flow
Figure 12-1 describes the flow of VLAN frames from the Ingress port to the
Egress port:
Figure 12-1. Frame Flow Through a VLAN
When a frame is received, it must be assigned a VLAN. VLAN assignment is
accomplished by the following steps:
1 If the frame contains a VLAN tag, that tag is used, otherwise the frame is
classified by the port's default VLAN (PVID), if it is defined.
2 After classification, the frame may pass (if enabled) through ingress
filtering, where the frame is dropped if the frame's VLAN ID is not one of
the VLANs to which the ingress port belongs.
3 A forwarding decision is made, as a function of the VLAN ID and the
destination MAC address.
Ingress Egress
VLAN
Classification
Ingress
Filtering
Egress
Filtering
Progress
Forwarding
Decision
Filtering
Database
Received
Frame
T ransmitted
Frame
Ingress Egress
VLAN
Classification
Ingress
Filtering
VLAN
Classification
Ingress
Filtering
Egress
Filtering
Progress
Forwarding
Decision
Filtering
Database
Received
Frame
T ransmitted
Frame