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BigIron RX Series Configuration Guide
341
53-1002253-01
IEEE Single Spanning Tree (SSTP)
12
SSTP uses the same parameters, with the same value ranges and defaults, as the default STP
supported on the device. Refer to
“Default STP bridge and port parameters”
on page 328.
SSTP defaults
SSTP is disabled by default. When you enable the feature, all VLANs on which STP is enabled
become members of a single spanning tree. All VLANs on which STP is disabled are excluded from
the single spanning tree:
•
To add a VLAN to the single spanning tree, enable STP on that VLAN.
•
To remove a VLAN from the single spanning tree, disable STP on that VLAN.
When you enable SSTP, all the ports that are in port-based VLANs with STP enabled become
members of a single spanning tree domain. Thus, the ports share a single BPDU broadcast
domain. The device places all the ports in a non-configurable VLAN, 4095, to implement the SSTP
domain. However, this VLAN does not affect port membership in the port-based VLANs you have
configured. Other broadcast traffic is still contained within the individual port-based VLANs.
Therefore, you can use SSTP while still using your existing VLAN configurations without changing
your network. In addition, SSTP does not affect 802.1q tagging. Tagged and untagged ports alike
can be members of the single spanning tree domain.
NOTE
When SSTP is enabled, the BPDUs on tagged ports go out untagged.
If you disable SSTP, all VLANs that were members of the single spanning tree run MSTP instead. In
MSTP, each VLAN has its own spanning tree. VLANs that were not members of the single spanning
tree were not enabled for STP. Therefore, STP remains disabled on those VLANs.
Enabling SSTP
NOTE
If the device has only one port-based VLAN (the default VLAN), then it is already running a single
instance of STP. In this case, you do not need to enable SSTP. You need to enable SSTP only if the
device contains more than one port-based VLAN and you want all the ports to be in the same STP
broadcast domain.
To configure the device to run a single spanning tree, enter the following command at the global
CONFIG level.
BigIron RX(config)# spanning-tree single
NOTE
If the device has only one port-based VLAN, the CLI command for enabling SSTP is not listed in the
CLI. The command is listed only if you have configured a port-based VLAN.
To change a global STP parameter, enter a command such as the following at the global CONFIG
level.
BigIron RX(config) spanning-tree single priority 2
This command changes the STP priority for all ports to 2.
To change an STP parameter for a specific port, enter commands such as the following.
BigIron RX(config) spanning-tree single ethernet 1/1 priority 10
Summary of Contents for BigIron RX Series
Page 228: ...152 BigIron RX Series Configuration Guide 53 1002253 01 Enabling WAN PHY mode support 6 ...
Page 312: ...236 BigIron RX Series Configuration Guide 53 1002253 01 Displaying IP information 7 ...
Page 356: ...280 BigIron RX Series Configuration Guide 53 1002253 01 Resetting LLDP statistics 9 ...
Page 402: ...326 BigIron RX Series Configuration Guide 53 1002253 01 Transparent firewall mode 11 ...
Page 432: ...356 BigIron RX Series Configuration Guide 53 1002253 01 SuperSpan 12 ...
Page 500: ...424 BigIron RX Series Configuration Guide 53 1002253 01 MRP CLI example 14 ...
Page 591: ...BigIron RX Series Configuration Guide 515 53 1002253 01 Displaying traffic reduction 19 ...
Page 592: ...516 BigIron RX Series Configuration Guide 53 1002253 01 Displaying traffic reduction 19 ...
Page 598: ...522 BigIron RX Series Configuration Guide 53 1002253 01 Viewing Layer 2 ACLs 20 ...
Page 656: ...580 BigIron RX Series Configuration Guide 53 1002253 01 Trunk formation 22 ...
Page 754: ...678 BigIron RX Series Configuration Guide 53 1002253 01 Displaying RIP filters 24 ...
Page 814: ...738 BigIron RX Series Configuration Guide 53 1002253 01 Displaying OSPF information 25 ...
Page 980: ...904 BigIron RX Series Configuration Guide 53 1002253 01 Clearing IS IS information 28 ...
Page 1000: ...924 BigIron RX Series Configuration Guide 53 1002253 01 Using secure copy 30 ...
Page 1088: ...1012 BigIron RX Series Configuration Guide 53 1002253 01 IP source guard 35 ...
Page 1108: ...1032 BigIron RX Series Configuration Guide 53 1002253 01 Reading CDP packets 37 ...
Page 1126: ...1050 BigIron RX Series Configuration Guide 53 1002253 01 Clearing sFlow statistics 39 ...
Page 1324: ...1248 BigIron RX Series Configuration Guide 53 1002253 01 Displaying OSPFv3 information 48 ...
Page 1363: ...BigIron RX Series Configuration Guide 1287 53 1002253 01 Continuous System Monitor 51 ...
Page 1364: ...1288 BigIron RX Series Configuration Guide 53 1002253 01 Continuous System Monitor 51 ...
Page 1404: ...1328 BigIron RX Series Configuration Guide 53 1002253 01 Commands That Require a Reload D ...
Page 1458: ...1382 BigIron RX Series Configuration Guide 53 1002253 01 VSRP E ...