Brocade Multi-Service IronWare Switching Configuration Guide (Supporting R05.6.00) - Manual (Page 475)

Multi-Service IronWare Switching Configuration Guide 445
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RSTP support for PB and PBB
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Figure 97 shows that BEB-1 and BEB-2 are connected via an IB tagged endpoint. The topology
convergence is the same as in Figure 96 . The difference comes in the BPDU transmitted out of the
IB tagged endpoint that will be a tunneled packet which will have a PBB header. In this topology the
IB- tagged end point should be always in the forwarding state by configuring either BEB-1 or BEB-2
as a ROOT bridge.
FIGURE 97 RSTP convergence when two AS connected via IB tagged endpoint
BPDU behavior on VPLS endpoints
1. By default, the BPDU generated from the VPLS end point will be with destination MAC of
00-00-00-00-00-08.
2. Upon receiving a BPDU with destination MAC 00-00-00-00-00-00, the RSTP will start
responding with that MAC on next transmitted BPDUs. (This is applicable for the VPLS VLAN
acting as a C-VLAN or S-VLAN.)
3. The VPLS B-VLAN end point will not respond for a tunneled BPDU with the STP MAC
00-00-00-00-00-00. It will be considered as a tunneled BPDU from customer bridges and be
tunneled across S-VLAN as well as C-VLAN.
4. The VPLS B-VLAN end point will be consuming the BPDU. Only when RSTP is enabled on the IB
tagged end point and received tunneled BPDU, it has a PBB-STP MAC. If RSTP is not enabled,
the received BPDU with PBB-STP MAC will be send to S-VLAN
Limitations
• Total RSTP instances is limited to 128, including regular VLAN and VPLS instances.
• RSTP Single is not supported in VPLS VLAN.
• The is no MIB support for PBB RSTP.
• Do not use the same VLAN ID for a regular VLAN and VPLS instance in the network. Enabling
RSTP on a regular VLAN and VPLS instance which has a VPLS VLAN with the same VLAN ID as
the regular VLAN ID can lead to an undesirable topology convergence.
• It is not possible to enable RSTP on a PBB VPLS instance if that instance has multiple VLANS
configured with same member ports.
BEB BEB
PB
DF DF
RF AD
DF - Designated Forwarding
RF - Root Forwarding
AD - Alternate Discarding
IB tagged endpoints
ROOT