Stp Config-Digest-Snooping - 3Com 8807 Command Reference Manual

14
Digest Snooping
Configuration
Commands
config-digest-snooping
D
IGEST
C
OMMANDS
stp Syntax

stp config-digest-snooping

undo stp config-digest-snooping
View
System view, Ethernet port view
Parameter
None
Description
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.
S
NOOPING
C
ONFIGURATION