HP ProCurve 5300xl Series Management Manual page 267

Figure 7-18. Connecting a Switch Mesh Domain to Non-Meshed Devices
Note on the Edge-
Port Mode in RSTP
and MSTP
When using RSTP or MSTP and interconnecting 3400cl, 6400cl, or 5300xl in a
mesh with switches that are not in the mesh, all the non-mesh switch ports
(as indicated in the figure above) should have the edge-port parameter dis­
abled. For more information on RSTP edge-port parameter see "Optimizing
the RSTP Configuration" on page 6-11
STP or RSTP should be configured on non-mesh devices that use redundant
links to interconnect with other devices or with multiple switch mesh
domains. For example:
Mesh Domain
Figure 7-19. Interconnecting Switch Mesh Domains with Redundant Links
In the above case of multiple switch meshes linked with redundant trunks
there is the possibility that spanning-tree will temporarily block a mesh link.
This is because it is possible for spanning-tree to interpret the cost on an
external trunked link to be less than the cost on a meshed link. However, if
Operating Notes for Switch Meshing
= Non-mesh Switch Ports
Non-Mesh Switch
STP
Block
STP
Block
Mesh Domain
Non-Mesh Switch
Switch Meshing
7-21