Specifications

Multilayer Switching Overview
Introduction to IP Multicast MLS
8
Figure 67 Basic IP Multicast MLS Network Topology
Benefits of multicast MLS are as follows:
• Improves throughput—The improves throughput feature improves the router’s multicast Layer 3
forwarding and replication throughput.
• Reduces load on router—If the router must replicate many multicast packets to many VLANs, it can
be overwhelmed as the input rate and number of outgoing interfaces increase. Configuring the
switch to replicate and forward the multicast flow reduces the demand on the router.
• Provides IP multicast scalability—If you need high throughput of multicast traffic, install a
Catalyst 5000 series switch and configure the Provides IP Multicast Scalability feature. By reducing
the load on your router, the router can accommodate more multicast flows.
• Provides meaningful flow statistics—IP multicast MLS provides flow statistics that can be used to
administer, plan, and troubleshoot networks.
IP Multicast MLS Components
An IP multicast MLS network topology has two components:
Router
Trunk link
VLANs 100, 200, 300
Trunk link
VLANs 100, 200, 300
G1
member
G1
member
G1
member
G1
source
VLAN 300
VLAN 200
VLAN 100
Router
(MMLS-RP)
G1
member
G1
member
G1
member
G1
source
VLAN 300
VLAN 200
VLAN 100
Switch
Switch
(MMLS-SE)
18952
Before IP multicast MLS
After IP multicast MLS
(completely switched)