9-26
Cisco ONS 15327 User Documentation, R3.3
June 2002
Chapter 9 Ethernet Operation
Spanning Tree (IEEE 802.1D)
Step 3
To put a port in a VLAN, click the port and choose either Tagged or Untag.
shows valid port
settings.
If a port is a member of only one VLAN, go to the row of that VLAN and choose
Untag
from the Port
column. Choose
--
for all the other VLAN rows in that Port column. The VLAN with
Untag
selected can
connect to the port, but other VLANs cannot access that port.
If a port is a trunk port, it connects multiple VLANs to an external device, such as a switch, that also
supports trunking. A trunk port must have tagging (IEEE 802.1Q) enabled for all VLANs that connect
to that external device. Choose
Tagged
for
all VLAN rows that need to be trunked. Choose
Untag
for
each of the VLAN rows in the trunk port column that do not need to be trunked, for example, the default
VLAN. Each Ethernet port must attached to at least one untagged VLAN.
Step 4
After each port is in the appropriate VLAN, click
Apply
.
Note
If Tagged is chosen, the attached external devices must recognize IEEE 802.1Q VLANs.
9.6 Spanning Tree (IEEE 802.1D)
The Cisco ONS 15327 operates Spanning Tree Protocol (STP) according to IEEE 802.1D when an
Ethernet card is installed. STP operates over all packet-switched ports including Ethernet and SONET
ports. On Ethernet ports, STP is disabled by default but may be enabled with a check box under the
Provisioning > Port tabs at the card-level view. On SONET interface ports, STP activates by default and
cannot be disabled.
The Ethernet card can enable STP on the Ethernet ports to allow redundant paths to the attached Ethernet
equipment. STP spans cards so that both equipment and facilities are protected against failure.
STP detects and eliminates network loops. When STP detects multiple paths between any two network
hosts, STP blocks ports until only one path exists between any two network hosts (
). The
single path eliminates possible bridge loops. This is crucial for shared packet rings, which naturally
include a loop.
Figure 9-23 STP-blocked path
Table 9-4
Port Settings
Setting
Description
--
A port marked with this symbol does not belong to the VLAN.
Untag
The ONS 15327 tags ingress frames and strips tags from egress frames.
Tagged
The ONS 15327 handles ingress frames according to VLAN ID; egress frames
do not have their tags removed.
43388
Redundant path (blocked)
Primary path (forwarding)
Содержание ONS 15327
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Страница 30: ...Figures xxviii Cisco ONS 15327 User Documentation June 2002 ...
Страница 44: ...Procedures xlii Cisco ONS 15454 Installation and Operations Guide R3 2 June 2002 ...
Страница 82: ...1 32 Cisco ONS 15327 User Documentation R3 3 June 2002 Chapter 1 Hardware Installation Hardware Specifications ...
Страница 166: ...4 22 Cisco ONS 15327 User Documentation R3 3 June 2002 Chapter 4 IP Networking ONS 15327 Routing Table ...
Страница 254: ...7 22 Cisco ONS 15327 User Documentation R3 3 June 2002 Chapter 7 Card Provisioning Using Virtual Wires ...
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Страница 540: ...Glossary GL 16 Cisco ONS 15327 User Documentation R3 3 June 2002 ...