Inhibiting PIM-DM Traffic from Flooding the Core

The Inhibiting PIM-DM Traffic from Flooding the Core feature enhances Multicast-VPNs (MVPNs) by introducing an intelligent mechanism to determine the Protocol Independent Multicast (PIM) mode of operation used by multicast distribution tree (MDT) tunnel interfaces. This feature is useful in preventing PIM dense mode (PIM-DM) traffic from flooding across an MVPN Multiprotocol Label Switching (MPLS) core when a Customer Edge (CE) router sends dense mode traffic into a Provider Edge (PE) router. Preventing dense mode traffic from flooding the core is important to conserving valuable bandwidth in the core.


Release	Modification
12.3(11)T	This feature was introduced.
12.2(27)SBC	This feature was integrated into Cisco IOS Release 12.2(27)SBC.

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Information About Inhibiting PIM-DM Traffic from Flooding the Core

To understand the Inhibiting PIM-DM Traffic from Flooding the Core feature, you should be familiar with the following concept:

How the Cisco IOS Software Intelligently Determines the PIM Mode of Operation Used by MDT Tunnel Interfaces

The Inhibiting PIM-DM Traffic from Flooding the Core feature inhibits dense mode traffic from flooding across an MVPN MPLS core by intelligently determining the PIM mode of operation for an MDT tunnel interface according to the PIM mode configured on the native interfaces that belong to a Multicast Virtual Routing and Forwarding (MVRF) instance.

Note The PIM mode of operation used by an MDT tunnel interface cannot be explicitly configured, and in previous Cisco IOS software releases, MDT tunnel interfaces only operated in sparse-dense mode, which potentially allowed dense mode traffic flooding if a CE router sent dense mode traffic into a PE router.

The following bulleted list describes the three possible MVRF native interface configuration scenarios and the corresponding PIM mode intelligently determined by MDT tunnel interfaces:

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If all native interfaces in the MVRF are configured to operate in sparse-dense or in dense mode, the MDT tunnel operates in sparse-dense mode.

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If all native interfaces in the MVRF are configured to operate in sparse mode, the MDT tunnel operates in sparse mode.

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If some native interfaces in the MVRF are configured to operate in sparse mode and some native interfaces are configured to operate in sparse-dense or dense mode, the MDT tunnel operates in sparse-dense mode.

Additional References

The following sections provide references related to the Inhibiting PIM-DM Traffic from Flooding the Core feature.

Related Documents


Related Topic	Document Title
IP multicast conceptual information	IP Multicast Technology Overview module in the Cisco IOS IP Multicast Configuration Guide, Release 12.4
Basic IP multicast configuration concepts, configuration tasks, and examples	"Configuring Basic IP Multicast" module in the Cisco IOS IP Multicast Configuration Guide, Release 12.4
Multicast-VPN concepts, configuration tasks, and examples	"Configuring Multicast-VPN" module in the Cisco IOS IP Multicast Configuration Guide, Release 12.4

Standards


Standard	Title
No new or modified standards are supported by this feature, and support for existing standards has not been modified by this feature.	—

MIBs


MIB	MIBs Link
No new or modified standards are supported by this feature, and support for existing standards has not been modified by this feature.	To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL: http://www.cisco.com/go/mibs

RFCs


RFC	Title
No new or modified RFCs are supported by this feature, and support for existing RFCs has not been modified by this feature.	—

Technical Assistance


Description	Link
The Cisco Technical Support website contains thousands of pages of searchable technical content, including links to products, technologies, solutions, technical tips, and tools. Registered Cisco.com users can log in from this page to access even more content.	http://www.cisco.com/techsupport

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