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Single vs. Multiple Spanning Tree
In previous releases of the Omni Switch/Router 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 pack-
ets 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 Omni Switch/Router 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
The above diagram shows how traffic on VLAN 1 is blocked between Switch 1 and Switch 2,
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Switch 1
Switch 2
Switch 3
VLAN 1
VLAN 1
VLAN 2
VLAN 2
Blocked
Physical
Port
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Switch 1
Switch 2
Switch 3
VLAN 1 (Blocked)
VLAN 1
VLAN 2
VLAN 1
VLAN 2 (Blocked)
VLAN 2
Содержание Omni Switch/Router
Страница 1: ...Part No 060166 10 Rev C March 2005 Omni Switch Router User Manual Release 4 5 www alcatel com ...
Страница 4: ...page iv ...
Страница 110: ...WAN Modules Page 3 40 ...
Страница 156: ...UI Table Filtering Using Search and Filter Commands Page 4 46 ...
Страница 164: ...Using ZMODEM Page 5 8 ...
Страница 186: ...Displaying and Setting the Swap State Page 6 22 ...
Страница 202: ...Creating a New File System Page 7 16 ...
Страница 270: ...Displaying Secure Access Entries in the MPM Log Page 10 14 ...
Страница 430: ...OmniChannel Page 15 16 ...
Страница 496: ...Configuring Source Route to Transparent Bridging Page 17 48 ...
Страница 542: ...Dissimilar LAN Switching Capabilities Page 18 46 ...
Страница 646: ...Application Example DHCP Policies Page 20 30 ...
Страница 660: ...GMAP Page 21 14 ...
Страница 710: ...Viewing the Virtual Interface of Multicast VLANs Page 23 16 ...
Страница 722: ...Application Example 5 Page 24 12 ...
Страница 788: ...Viewing UDP Relay Statistics Page 26 24 ...
Страница 872: ...The WAN Port Software Menu Page 28 46 ...
Страница 960: ...Deleting a PPP Entity Page 30 22 ...
Страница 978: ...Displaying Link Status Page 31 18 ...
Страница 988: ...Displaying ISDN Configuration Entry Status Page 32 10 ...
Страница 1024: ...Backup Services Commands Page 34 14 ...
Страница 1062: ...Diagnostic Test Cable Schematics Page 36 24 ...
Страница 1072: ...Configuring a Switch with an MPX Page A 10 ...
Страница 1086: ...Page B 14 ...
Страница 1100: ...Page I 14 Index ...