Pim Stub Routing - Cisco Catalyst 3850 series Configuration Manual

PIM Stub Routing

• PIM join and prune messages have more flexible encoding for multiple address families.
• A more flexible hello packet format replaces the query packet to encode current and future capability
• Register messages sent to an RP specify whether they are sent by a border router or a designated router.
• PIM packets are no longer inside IGMP packets; they are standalone packets.
Related Topics
Troubleshooting PIMv1 and PIMv2 Interoperability Problems, on page 181
PIMv1 and PIMv2 Interoperability, on page 122
PIM Stub Routing
The PIM stub routing feature, available in all of the device software images, reduces resource usage by moving
routed traffic closer to the end user.
The PIM stub routing feature supports multicast routing between the distribution layer and the access layer.
It supports two types of PIM interfaces, uplink PIM interfaces, and PIM passive interfaces. A routed interface
configured with the PIM passive mode does not pass or forward PIM control traffic, it only passes and forwards
IGMP traffic.
In a network using PIM stub routing, the only allowable route for IP traffic to the user is through a device
that is configured with PIM stub routing. PIM passive interfaces are connected to Layer 2 access domains,
such as VLANs, or to interfaces that are connected to other Layer 2 devices. Only directly connected multicast
(IGMP) receivers and sources are allowed in the Layer 2 access domains. The PIM passive interfaces do not
send or process any received PIM control packets.
When using PIM stub routing, you should configure the distribution and remote routers to use IP multicast
routing and configure only the device as a PIM stub router. The device does not route transit traffic between
distribution routers. You also need to configure a routed uplink port on the device. The device uplink port
cannot be used with SVIs. If you need PIM for an SVI uplink port, you should upgrade to the IP Services
feature set.
You must also configure EIGRP stub routing when configuring PIM stub routing on the device
Note
The redundant PIM stub router topology is not supported. The redundant topology exists when there is more
than one PIM router forwarding multicast traffic to a single access domain. PIM messages are blocked, and
the PIM asset and designated router election mechanisms are not supported on the PIM passive interfaces.
Only the nonredundant access router topology is supported by the PIM stub feature. By using a nonredundant
topology, the PIM passive interface assumes that it is the only interface and designated router on that access
domain.
IP Multicast Routing Configuration Guide, Cisco IOS XE Release 3.6E (Catalyst 3850 Switches)
128
options.
Configuring PIM
OL-32598-01