Extreme 3804 Mode D'Emploi

7-2

S

UMMIT

 S

WITCH

 I

NSTALLATION

 

AND

 U

SER

 G

UIDE

S

PANNING

 T

REE

 P

ROTOCOL

 (STP)

A port can belong to only one STPD. If a port is a member of multiple VLANs, then all 
those VLANs must belong to the same STPD.

The key points to remember when configuring VLANs and STP are the following:

Each VLAN forms an independent broadcast domain.

STP blocks paths to create a loop-free environment.

When STP blocks a path, no data can be transmitted or received on the blocked port.

Within any given STPD, all VLANs belonging to it use the same spanning tree.

Care must be taken to ensure that STPD instances within a single Summit 
switch do not see each other in the same broadcast domain. This could happen 
if, for example, another external bridge is used to connect VLANs belonging to 

separate STPDs.

If you delete a STPD, the VLANs that were members of that STPD are also deleted. You 
must remove all VLANs associated with the STP before deleting the STPD.

The default device configuration contains a single STPD called s0. The default VLAN is 
a member of STPD s0. 

All STP parameters default to the IEEE 802.1D values, as appropriate.

STP C

ONFIGURATIONS

When you assign VLANs to an STPD, pay careful attention to the STP configuration 
and its effect on the forwarding of VLAN traffic. 

 illustrates a network that uses VLAN tagging for trunk connections. The 

following four VLANs have been defined:

Sales is defined on Switch A, Switch B, and Switch M.

Personnel is defined on Switch A, Switch B, and Switch M.

Manufacturing is defined on Switch Y, Switch Z, and Switch M.

Engineering is defined on Switch Y, Switch Z, and Switch M.

Marketing is defined on all switches (Switch A, Switch B, Switch Y, Switch Z, and 
Switch M).

Summit.bk : 7STP.FM  Page 2  Thursday, June 18, 1998  9:27 AM