Optimized Edge Routing Configuration Guide, Cisco IOS Release 15.1M&T
Using Performance Routing to Control EIGRP Routes with mGRE DMVPN Hub-and-Spoke Support
Using Performance Routing to Control EIGRP Routes with mGRE DMVPN Hub-and-Spoke Support
Last Updated: May 29, 2012
The PfR EIGRP mGRE DMVPN Hub-and-Spoke Support feature introduces the ability to inject routes into the EIGRP routing table, which allows Performance Routing (PfR) to control prefixes and applications over EIGRP routes. This feature also adds support for multicast Generic Routing Encapsulation (mGRE) Dynamic Multipoint Virtual Private Network (DMVPN) deployments that follow a hub- and-spoke network design.
Performance Routing is an extension of the Optimized Edge Routing (OER) technology and many of the commands and command modes still use the OER naming conventions. All of the original OER features are incorporated into the Performance Routing technology. Some of the early OER features have been superseded by newer techniques, and the more recent configuration module titles now use Performance Routing naming.
Finding Feature Information
Your software release may not support all the features documented in this module. For the latest feature information and caveats, see the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the Feature Information Table at the end of this document.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.
Prerequisites for Using PfR to Control EIGRP Routes
This feature assumes that EIGRP is already configured in your network and that basic OER functionality is also configured. See the Cisco IOS Optimized Edge Routing Overview and Setting Up OER Network Components modules for more details. For other OER and PfR features, see the Where to Go Next section or the Additional References section for more details.
Restrictions for Using PfR to Control EIGRP Routes
If you are deploying EIGRP in an mGRE DMVPN topology in your network, it must conform to a hub- and-spoke network design.
Information About Using PfR to Control EIGRP Routes
PfR EIGRP Route Control
The PfR EIGRP mGRE DMVPN Hub-and-Spoke Support feature introduces PfR route control for EIGRP. When enabled, a parent route check is performed in the EIGRP database for controlling PfR prefixes and routes in addition to the existing BGP and static route databases.
PfR can only optimize paths for prefixes, which have an exact matching route or a less specific route (also called as parent route) in the routing protocols. The route being controlled by PfR can be an exact match of the parent route or can be a more specific one. For example, if PfR wants to control 10.1.1.0/24 but the EIGRP routing table has only 10.1.0.0/16 then the parent route is 10.1.0.0/16 and PfR will inject 10.1.1.0/24 in the EIGRP routing table.
If an exact matching parent route in the EIGRP routing table is found, PfR will attempt to install a route on an exit selected by the master controller by influencing the metric. If an exact match parent is not found, then PfR introduces a new route in the EIGRP table that matches the attributes of the parent. If the route installation in the EIGRP table is successful, PfR saves the EIGRP parent and registers for any updates to the parent route. If the parent route is removed, PfR will uncontrol any routes it has installed in the EIGRP table based on this parent route.
PfR monitors traffic performance for prefixes it is controlling either passively using NetFlow or actively using IP SLA probes. Performance statistics such as delay, loss, and reachability are gathered and compared against a set of policies configured for the prefixes. If the traffic performance does not conform to the policies, the prefix is said to be out-of-policy (OOP). PfR tries to find an alternate path when the prefix goes into the OOP state.
While both BGP and static route control are enabled by default, EIGRP route control must be configured. PfR always attempts to control a prefix using BGP first. If BGP route control fails, static route control is tried. When EIGRP route control is enabled, PfR will attempt to control a prefix using BGP first. If no parent route is found, PfR will try to use EIGRP route control. If EIGRP route controls fails, static route control is tried.
To find an alternate path for a prefix, PfR tries to send active probes from all the external interfaces on the border routers to a set of hosts in the destination prefix network. Before an active probe can be sent on an external interface, a parent route lookup is performed in routing protocol tables. When the PfR EIGRP mGRE DMVPN Hub-and-Spoke Support feature is enabled, PfR checks EIGRP routing tables, in addition to BGP and static routing tables, for a parent route, before sending active probes on external interfaces. Active probes are initiated on all the external interfaces that have a parent route in the EIGRP routing table. When the probe activity completes and the timer expires, statistics are sent from the border router to the master controller for policy decision and selection of an optimal exit.
When an exit is selected, a control prefix command is sent to the border router with the selected exit, specifying EIGRP as the protocol to install or modify the route. When the border router receives the command, it checks the EIGRP table to find a parent route. If a parent route is found, OER will install or modify the route in the EIGRP table and will notify the master controller about the route control status.
If an EIGRP route is successfully installed and advertised into the domain, OER continues to monitor traffic performance for this prefix and takes further action as mentioned above if the prefix goes OOP.
For more details about the PfR control mode and details about other PfR exit link selection control techniques including BGP, static routes, policy-based routing, and Protocol Independent Route Optimization (PIRO), see the Using OER to Control Traffic Classes and Verify the Route Control Changes module.
PfR and mGRE Dynamic Multipoint VPN
Dynamic Multipoint VPN (DMVPN) enables zero-touch deployment of IPsec encrypted VPN networks. The DMVPN topology leverages protocols like multipoint GRE (mGRE) for hub-to-spoke functionality, and for spoke-to-spoke functionality it utilizes the Next Hop Resolution Protocol (NHRP). Many DMVPN deployments use EIGRP networks, and support was added to PfR to allow DMVPN network deployments to use EIGRP route control within the DMVPN network. In the PfR EIGRP route control implementation, only hub-to-spoke network designs are supported.
For more details about configuring mGRE DMVPN networks, see the Dynamic Multipoint VPN module. For general information about DMVPN, go to http://www.cisco.com/go/dmvpn .
How to Configure PfR to Control EIGRP Routes
Enabling PfR EIGRP Route Control and Setting a Community Value
Perform this task on the master controller to enable EIGRP route control. While both BGP and static route control are enabled by default, EIGRP route control must be enabled using a command-line interface (CLI) command, mode route metric eigrp. PfR always attempts to control a prefix using BGP first. If BGP route control fails, static route control is tried. When EIGRP route control is enabled, PfR will attempt to control a prefix using BGP first. If no parent route is found, PfR will try to use EIGRP route control. If EIGRP route controls fails, static route control is tried.
This task can also set an extended community value for an injected EIGRP route to allow the routes to be uniquely identified. An EIGRP route may be injected by PfR to control the traffic defined by a traffic class when it goes out-of-policy (OOP). In this task, the PfR route control mode is configured globally with the mode route control command in OER master controller configuration mode, and any injected EIGRP routes will be tagged with a value of 700.
Disabling PfR EIGRP Route Control
Perform this task on the master controller to disable EIGRP route control.
2. configure terminal
3. oer master
4. no mode route metric eigrp
Manually Verifying the PfR EIGRP-Controlled Routes
PfR automatically verifies route control changes in the network using NetFlow output. PfR monitors the NetFlow messages and uncontrols a traffic class if a message does not appear to verify the route control change. Perform the steps in this optional task if you want to manually verify that the traffic control implemented in the PfR control phase actually changes the traffic flow, and brings the OOP event to be in-policy.
All the steps in this task are optional and are not in any order. The information from these steps can verify that a specific prefix associated with a traffic class has been moved to another exit or entrance link interface, or that it is being controlled by PfR. The first two commands are entered at the master controller, the last two commands are entered at a border router.
Only partial command syntax for some of the show commands used in this task is displayed. For more details about OER show commands, see the Cisco IOS Optimized Edge Routing Command Reference.
If the show commands are not displaying output that verifies the EIGRP route control, use the debug oer border routes eigrp command with the optional detail keyword for more information. Debugging must be enabled before entering the required commands, and the debug output depends on which commands are subsequently entered.
Configuration Examples for Using PfR to Control EIGRP Routes
Enabling PfR EIGRP Route Control and Setting a Community Value Example
Where to Go Next
This module covers PfR EIGRP route control. To learn more about PfR, start with the Cisco IOS Optimized Edge Routing Overview and the Setting Up OER Network Components modules. To learn more about the OER phases (same as Performance Routing phases) identified in the Cisco IOS Optimized Edge Routing Overview module, read through the other modules in the following list:
Feature Information for Using PfR to Control EIGRP Routes
The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.
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