Foundry NetIron M2404C and M2404F Metro Access Switches
Configuring MSTP (Rev. 03)
Overview
© 2008 Foundry Networks, Inc
Page 20 of 70
Prerequisites
The MSTP implementation operates over MSTIs, which are in turn, mapped into groups of VLANs.
However, since MSTP does not enforce VLAN membership state for ports, a situation of
inconsistency between the MSTP port’s state and the real state of the port may arise. For example,
MSTP may set a port state on MSTI3 to be forwarding, when the instance is mapped to VLANs 3-
5. If the port is not a member of VLAN 4, it will effectively be blocked on that VLAN, although
MSTP will show a forwarding state.
Make sure that this consistency is maintained, either by matching the VLAN memberships to the
MSTP state or by changing MSTP parameters (such as path-cost and priority) so the traffic will be
diverted to correct ports.
NOTE
For more details on how to configure an H-VPLS application in a MSTP-guarded
fast-ring topology refer to chapter “
Configuring Multiprotocol Label Switching
(MPLS) and Hierarchical Virtual Private LAN Services (H-VPLS)
”.
NOTE
MSTP uses a single Access List resource for each Gigabit Ethernet port/each
group of 8 Fast-Ethernet ports.
To understand resource allocation of Access Lists please refer to chapter
“
Configuring Access Control Lists (ACLs)”.
MSTP Configuration Flow
The following flow chart shows the process of configuring the MSTP parameters.