Netgear XCM8806 - 8800 SERIES 6-SLOT CHASSIS SWITCH 사용자 설명서

desirable to have multiple STP domains operating in a single VLAN, one for each looped 
area. 

The justifications include the following:

The complexity of the STP algorithm increases, and performance drops, with the size and 

complexity of the network. The 802.1D standard specifies a maximum network diameter 
of seven hops. By segregating a big VLAN into multiple STPDs, you reduce complexity 
and enhance performance.

Local to each site, there may be other smaller VLANs that share the same redundant 

looped area with the large VLAN. Some STPDs must be created to protect those VLANs. 
The ability to partition VLANs allows the large VLAN to be “piggybacked” in those STPDs 
in a site-specific fashion.

 has five domains. VLANs green, blue, brown, and yellow are local to each domain. 

VLAN red spans all of the four domains. Using a VLAN that spans multiple STPDS, you do 
not have to create a separate domain for VLAN red. Instead, VLAN red is “piggybacked” onto 
those domains local to other VLANs.

In addition, the configuration in 

 has these features:

Each site can be administered by a different organization or department within the 

enterprise. Having a site-specific STP implementation makes the administration more 
flexible and convenient.

Between the sites the connections usually traverse distribution switches in ways that are 

known beforehand to be “safe” with STP. In other words, the looped areas are already 
well-defined.

EMISTP Deployment Constraints

Although EMISTP greatly enhances STP capability, these features must deployed with care. 
This section describes configuration issues that, if not followed, could lead to an improper 
deployment of EMISTP. This section also provides the following restrictive principles to abide 
by in network design:

EX_051

VLAN yellow

VLAN red

VLAN red

VLAN brown

VLAN red

VLAN green

VLAN red

VLAN blue