Bpdu Tunneling Implementation - HP 3100 Series Configuration Manual

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Link Layer Discovery Protocol (LLDP)
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Per VLAN Spanning Tree (PVST)
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Spanning Tree Protocol (STP)
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Unidirectional Link Direction (UDLD)
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VLAN Trunking Protocol (VTP)

BPDU tunneling implementation

The BPDU tunneling implementations for different protocols are all similar. This section uses the
Spanning Tree Protocol (STP) to describe how to implement BPDU tunneling.
This document uses the term STP 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 "Configuring spanning tree protocols."
To avoid loops in your network, you can enable STP on your devices. When the topology changes at
one side of the customer network, devices at that side of the customer network send BPDUs to
devices 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 devices, 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.
BPDU tunneling allows each network to calculate an independent spanning tree with STP.
BPDU tunneling delivers the following benefits:
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BPDUs can be transparently transmitted. BPDUs of one customer network can be broadcast in
a specific VLAN across the service provider network, allowing that customer's geographically
dispersed networks to implement consistent spanning tree calculation across the service
provider network.
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BPDUs of different customer networks can be confined within different VLANs for transmission
on the service provider network. This enables each customer network to perform independent
spanning tree calculation.
Figure 29 BPDU tunneling implementation
The upper section of
section, including User A network 1 and User A network 2, represents the customer networks.
Enabling BPDU tunneling on edge devices (PE 1 and PE 2) in the service provider network allows
BPDUs of User A network 1 and User A network 2 to be transparently transmitted through the service
provider network. This ensures consistent spanning tree calculation throughout User A network,
without affecting the spanning tree calculation of the service provider network.
Assume that a BPDU is sent from User A network 1 to User A network 2. The BPDU is sent by using
the following workflow:
Figure 29 represents the service provider network (ISP network). The lower
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