3com 8807 참조 가이드

stp config-digest-snooping

undo stp config-digest-snooping

System view, Ethernet port view

None

Use the stp config-digest-snooping command to enable digest snooping.

Use the undo stp config-digest-snooping command to disable digest snooping.

Digest snooping is disabled by default.

According to IEEE 802.1s, two connected switches can communicate with each 
other through multiple spanning tree instances (MSTIs) in a multiple spanning tree 
protocol (MSTP) domain only when they are configured with the same domain 
settings. With MSTP employed, interconnected switches determine whether or not 
they are in the same domain by checking the configuration IDs of the bridge 
protocol data units (BPDUs) between them. (A configuration ID comprises 
information such as domain ID, configuration digest.)

As switches of some manufacturers come with some proprietary protocols 
concerning spanning trees employed, a switch of this type cannot communicate 
with other switches in an MSTP domain even if it is configured with the same 
domain settings as other switches in the MSTP domain.

This kind of problems can be overcome by implementing digest snooping. Digest 
snooping enables a switch to track and maintain configuration digests of other 
switches that are in the same domain and come from other manufacturers by 
examining their BPDUs. It also enables the switch to insert corresponding 
configuration digests in its BPDUs destined for these switches. In this way, 
switches of different manufacturers are capable of communicating with each 
other in an MSTP domain.