Cisco Catalyst 3850 series User Manual

Enable ECMP multicast load splitting on the device that is to be the receiver for traffic from more than
one incoming interfaces, which is opposite to unicast routing. From the perspective of unicast, multicast
is active on the sending device connecting to more than one outgoing interfaces.
Note
Before You Begin
•
You must have an adequate number of sources (at least more than two sources) to enable ECMP multicast
load splitting based on source address.
•
You must have multiple paths available to the RP to configure ECMP multicast load splitting.
Use the show ip route command with either the IP address of the source for the
ip-addressargument or the IP address of the RP to validate that there are multiple paths
available to the source or RP, respectively. If you do not see multiple paths in the output
of the command, you will not be able to configure ECMP multicast load splitting.
Note
•
When using PIM-SM with shortest path tree (SPT) forwarding, the T-bit mus be set for the forwarding
of all (S, G) states.
•
Before configuring ECMP multicast load splitting, it is best practice to use the show ip rpf command
to validate whether sources can take advantage of IP multicast multipath capabilities.
•
BGP does not install multiple equal-cost paths by default. Use the maximum-paths command to configure
multipath (for example in BGP). For more information, see the Use of BGP with ECMP Multicast Load
Splitting, on page 359 section.
SUMMARY STEPS
1.
enable
2.
configure terminal
3.
ip multicast multipath
4.
Repeat step 3 on all the devices in a redundant topology.
5.
exit
6.
show ip rpf source-address [group-address]
7.
show ip route ip-address
DETAILED STEPS
PurposeCommand or Action
Enables privileged EXEC mode.enable
Step 1
Example:
Device> enable
•
Enter your password if prompted.
IP Multicast Routing Configuration Guide, Cisco IOS XE Release 3.6E (Catalyst 3850 Switches)
362 OL-32598-01
IP Multicast Optimization: IP Multicast Load Splitting across Equal-Cost Paths
Enabling ECMP Multicast Load Splitting

Cisco Catalyst 3850 series Specifications

General

Model	Cisco Catalyst 3850 Series
RAM	4 GB
Flash Memory	4 GB
Stacking Bandwidth	480 Gbps
Device Type	Switch
Enclosure Type	Rack-mountable
Routing Protocol	OSPF, EIGRP, BGP, RIP
Remote Management Protocol	SNMP, CLI, HTTP, HTTPS
Features	Quality of Service (QoS)
Stacking	Yes
Memory	4 GB RAM
Operating System	Cisco IOS
Relative Humidity	10 - 95% (non-condensing)
Power Supply Options	AC or DC
Ports	24 or 48 10/100/1000 Ethernet ports