Understanding the network.pdf - Back to Home

ULP-based VLANs are a comparatively new and useful class of VLAN.
Depending on VLAN implementation, VLAN membership can be based
on IP, IPX, AppleTalk, and other popular LAN protocols. However,
Layer 3-based VLANs operate at a slower processing rate. Examining
each packet well into the datagram portion of the packet is time
consuming in comparison to looking at a MAC address. Multicast
VLANs consume even more switch resources than basic Layer 3 switch
VLAN variations. This is because the switch not only needs to examine
the Layer 3 portion of the packet, it also needs to maintain
membership lists of the hosts involved in the multicast groups, along
with maintaining distinct VLANs for each multicast group.
VLAN Configuration and Implementation
Regardless of the VLAN membership methodology, VLAN
implementations represent an additional level of network complexity
beyond the traditional plug-and-play "one network, one wire"
approach. When VLANs first appeared, they were limited to a
standalone switch, which meant that VLANs in large networks were
really only useful for creating broadcast domain port groups, which
could be connected to another switch or router that was part of the
same Layer 3 network. Figure 6.13 provides a simple example.