Alcatel OmniAccess 512 Manual de usuario descargar pdf (Pagina 4)

Page 13-4

Single vs. Multiple Spanning Tree

In previous releases of the OmniAccess 512 software (4.0 and earlier), spanning tree support

was done on a per port basis. In other words, a physical port could only participate in one

instance of a spanning tree on the network. If a network is passing both untagged and IEEE

tagged frames, single spanning tree support could lead to packets being lost. Lost packets

could occur if a port specifically assigned to handle one type of traffic (e.g. IEEE 802.1Q) is

blocked by spanning tree, forcing traffic for that port to move to a port not assigned to handle

IEEE 802.1Q traffic.

Port Based Spanning Tree

In the above diagram, the physical connection between Switch 1 and Switch 2 is blocked by

spanning tree. No traffic can pass over the connected ports.

Release 4.1 (and later) of the OmniAccess 512 allows for multiple spanning tree instances on

a single port. Put another way, a port can be part of separate spanning trees, with no impact

on packet delivery. This is done by basing spanning tree configuration on groups rather than

physical ports.

Group Based Spanning Tree

Switch 1

Switch 2

Switch 3

VLAN 1

VLAN 2

Blocked

Physical

Port

Switch 1

Switch 2

Switch 3

VLAN 1 (Blocked)

VLAN 1

VLAN 2

VLAN 1

VLAN 2 (Blocked)

VLAN 2

1 2 3 4 5 6 7 8 9 10

Sin comentarios

Alcatel OmniAccess 512 Manual de usuario Pagina 4