18-8
Cisco IE 2000 Switch Software Configuration Guide
OL-25866-01
Chapter 18 Configuring VTP
Information About Configuring VTP
Figure 18-1 Flooding Traffic without VTP Pruning
Figure 18-2 shows a switched network with VTP pruning enabled. The broadcast traffic from Switch A
is not forwarded to Switches C, E, and F because traffic for the Red VLAN has been pruned on the links
shown (Port 5 on Switch B and Port 4 on Switch D).
Figure 18-2 Optimized Flooded Traffic with VTP Pruning
With VTP versions 1 and 2, enabling VTP pruning on a VTP server enables pruning for the entire
management domain. Making VLANs pruning-eligible or pruning-ineligible affects pruning eligibility
for those VLANs on that trunk only (not on all switches in the VTP domain). In VTP version 3, you must
manually enable pruning on each switch in the domain.
See the “Enabling VTP Pruning” section on page 18-13. VTP pruning takes effect several seconds after
you enable it. VTP pruning does not prune traffic from VLANs that are pruning-ineligible. VLAN 1 and
VLANs 1002 to 1005 are always pruning-ineligible; traffic from these VLANs cannot be pruned.
Extended-range VLANs (VLAN IDs higher than 1005) a re also pruning-ineligible.
Switch D
Switch E
Switch CSwitch F Switch A
Switch B
Port 1
Port 2
Red
VLAN
89240
Switch D
Switch E
Switch CSwitch F Switch A
Switch B
Port 1
Port 2
Red
VLAN
89241
Port
4
Flooded traffic
is pruned.
Port
5
Flooded traffic
is pruned.