Cisco 2950 - Catalyst Switch Configuration Manual page 399

Chapter 18 Configuring VTP
Figure 18-1 Flooding Traffic without VTP Pruning
Switch F
Figure 18-2
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
Flooded traffic
is pruned.
Switch E
Switch F
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 device
only (not on all switches in the VTP domain). See the
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) are
also pruning-ineligible.
78-11380-10
Switch D
Switch E
Switch B
Switch C
shows a switched network with VTP pruning enabled. The broadcast traffic from Switch A
Switch D
Port 2
Port
4
Switch B
Flooded traffic
is pruned. Port
5
Switch C
Port 2
Red
VLAN
Port 1
Switch A
Red
VLAN
Port 1
Switch A
"Enabling VTP Pruning" section on page
Catalyst 2950 and Catalyst 2955 Switch Software Configuration Guide
Understanding VTP
18-14.
18-5