Configuring Digest Snooping; Configuration Prerequisites; Configuration Procedure - 3Com MSR 50 Series Configuration Manual

Configuring Digest
Snooping
Configuration
Prerequisites

Configuration Procedure

Method 2: Perform mCheck in Ethernet interface view
<Sysname> system-view
[Sysname] interface ethernet 1/0
[Sysname-Ethernet1/0] stp mcheck
As defined in IEEE 802.1s, interconnected devices are in the same region only
when the region related configuration (domain name, revision level,
VLAN-to-instance mappings) on them is identical. An MSTP enabled device
identifies devices in the same MST region via checking the configuration ID in
BPDU packets. The configuration ID includes the region name, revision level,
configuration digest that is in 16-byte length and is the result computed via the
HMAC-MD5 algorithm based on VLAN-to-instance mappings.
Since MSTP implementations differ with vendors, the configuration digest
computed using private key is different; hence different vendors' devices in the
same MST region can not communicate with each other.
Enabling the Digest Snooping feature on the associated port can make a device
communicate with another vendor's device in the same MST region.
Associated devices of different vendors are interconnected and run MSTP.
Follow these steps to configure Digest Snooping:
To do...
Enter system view
Enter Ethernet Enter Ethernet
interface view interface view
or port group
Enter port
view
group view
Enable digest snooping on the
interface
Return to system view
Enable digest snooping
globally
c
CAUTION:
You can only enable the Digest Snooping feature on the device connected to
■
another vendor's device that use private key to compute the configuration
digest.
With the Digest Snooping feature enabled, comparison of configuration digest
■
is not needed for in-the-same-region check, so the VLAN-to-instance mappings
must be the same on associated ports.

Configuring Digest Snooping

Use the command...
system-view
interface interface-type
interface-number
port-group { manual
port-group-name |
aggregation agg-id }
stp config-digest-snooping Required
quit
stp config-digest-snooping Optional
475
Remarks
-
User either command
Configured in Ethernet
interface view, the setting is
effective on the current port
only; configured in port
group view, the setting is
effective on all ports in the
port group.
Not enabled by default
-
Not enabled by default