Bpdu Tunneling Implementation - HP A6600 Configuration Manual

• HGMP
• LACP
• LLDP
• PAGP
PVST
•
STP
•
UDLD
•
VTP
•

BPDU tunneling implementation

The BPDU tunneling implementations for different protocols are all similar. This section describes how
BPDU tunneling is implemented by taking the STP as an example.
The term STP in this document is in a broad sense. It includes STP, RSTP, and MSTP.
STP calculates the topology of a network by transmitting BPDUs among devices in the network. For more
information, see the chapter "MSTP configuration."
To avoid loops in your network, enable STP on your routers. When the topology changes at one side of
the customer network, the routers at this side of the customer network send BPDUs to routers on the other
side of the customer network to ensure consistent spanning tree calculation in the entire customer network.
However, because BPDUs are Layer 2 multicast frames, all STP-enabled routers, both in the customer
network and in the service provider network, can receive and process these BPDUs. In this case, neither
the service provider network nor the customer network can correctly calculate its independent spanning
tree.
To allow each network to calculate an independent spanning tree with STP, BPDU tunneling was
introduced.
BPDU tunneling delivers the following benefits:
• BPDUs can be transparently transmitted. BPDUs of the same customer network can be broadcast in a
specific VLAN across the service provider network, so that the geographically dispersed networks of
the same customer can implement consistent spanning tree calculation across the service provider
network.
BPDUs of different customer networks can be confined within different VLANs for transmission on the
•
service provider network. Thus, each customer network can perform independent spanning tree
calculation.
Figure 26 Network diagram for BPDU tunneling implementation
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