Overview
The Virtual Routing and Forwarding (VRF) feature allows Cisco Unified Border Element (CUBE) to have multiple instances of routing and forwarding table to co-exist on the same device at the same time.
With Multi-VRF feature, each interface or subinterface can be associated with a unique VRF.
Note |
The information in this chapter is specific to Multi-VRF feature beginning in Cisco IOS Release 15.6(2)T. However, there is some information on Voice-VRF feature for the reference purpose only. For detailed information on the Voice-VRF feature, see http://www.cisco.com/c/en/us/td/docs/ios/12_4t/12_4t15/vrfawvgw.html. |
Feature Information
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.
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.
Feature Name |
Releases |
Feature Information |
---|---|---|
Support for media flow-around using Multi-VRF |
Cisco IOS XE Gibraltar 16.12.2 |
This feature adds media flow-around support for the following intra-VRF call flows in standalone and high availability scenarios:
With media flow-around using Multi-VRF, only signalling is routed using VRFs and CUBE passes across the media IP and ports which it receives. For detailed information on media flow-around, see Media Path. |
Support up to 100 VRF instances |
Cisco IOS XE Amsterdam 17.3.1 |
This feature enhancement provides support up to 100 VRFs. Each of the VRFs supports up to 10 different RTP port ranges. |
Information About Voice-VRF
Support for Voice-VRF (also known as VRF-Aware) was introduced in Cisco IOS Release 12.4(11)XJ to provide support for configuring a VRF specific to voice traffic. Voice-VRF can be configured using voice vrf vrf-name command. For more information on voice-VRF, see http://www.cisco.com/c/en/us/td/docs/ios/12_4t/12_4t15/vrfawvgw.html.
Information About Multi-VRF
The Multi-VRF feature allows you to configure and maintain more than one instance of routing and forwarding tables within the same CUBE device and segregate voice traffic based on the VRF.
Multi-VRF uses input interfaces to distinguish calls for different VRFs and forms VRF tables by associating with one or more Layer 3 interfaces. Interface can be physical interface (such as FastEthernet ports, Gigabit Ethernet ports) or sub-interface. CUBE supports bridging calls on both intra-VRF and inter-VRF.
Note |
One physical interface or sub-interface can be associated with one VRF only. One VRF can be associated with multiple interfaces. |
As per the Multi-VRF feature, the dial-peer configuration must include the use of the interface bind functionality. This is mandatory. It allows dial-peers to be mapped to a VRF via the interface bind.
The calls received on a dial-peer are processed based on the interface to which it is associated with. The interface is in turn associated with the VRF. So, the calls are processed based on the VRF table associated with that particular interface.
VRF Preference Order
Voice-VRF and Multi-VRF configurations can coexist. The following is the binding preference order for call processing:
Preference Order |
Bind |
Recommendations |
---|---|---|
1 |
Dial-peer Bind |
— |
2 |
Tenant Bind |
Recommended for SIP trunk, especially when CUBE is collocated with Cisco Unified Survivability Remote Site Telephony. If Tenant bind is not configured, Voice-VRF is preferred for SIP trunk. |
3 |
Global Bind |
During device reboot, it is recommended to use global bind configuration to handle the early incoming traffic gracefully. |
4 |
Voice-VRF |
Recommended for hosted and cloud services configurations when CUBE is collocated with Cisco Unified Survivability Remote Site Telephony. |