Chapter 15: Interface IP Configuration
STANDARD Revision 1.0
C4® CMTS Release 8.3 User Guide
© 2016 ARRIS Enterprises LLC. All Rights Reserved.
442
Multiple VRF Functionality
Both cable and network side interfaces can be configured and assigned to a VRF instance.
Network side interfaces must use QTAGs to create logical subinterfaces which may be assigned to a VRF. Cable side
interfaces use the SIP of the ingress packets to associate a logical subinterface with a VRF instance.
Note: For IPv6, ingress link local packets on cable-mac interfaces are handled differently than packets with globally
scoped SIPs.
All ingress IPv6 packets with a SIP and DIP that use a link local address are mapped to the lowest sub-interface
associated with the cable-mac with the following exceptions:
Neighbor Solicitations and Neighbor Advertisements with a destination address or a target address that is globally
scoped are mapped to the sub-interface and VRF of the globally scoped IP address prefix.
Router Solicitations are fanned out to all sub-interfaces associated with the cable-mac.
Multiple instances of VRFs can be created, each with its own route table, interfaces, protocol instances, and so on.
A
default
VRF instance is always automatically created. This VRF includes all of the interfaces not explicitly assigned to
other VRFs.
The
default
VRF has a special property that enables it to route traffic to any directly connected subnet in any other
VRF for which the auto-import property is enabled.
Data traffic is isolated by VRF.
Data traffic between two devices within the same VRF scope will be routed within the C4/c CMTS. Data traffic between
two devices in separate VRF scopes will not be routed within the C4/c CMTS unless explicitly configured.
The VRF feature supports IPv4 and IPv6.
There are limits to the number of VRFs and the number of configured routing protocol instances. See
(page 443). Contact ARRIS Tech Support when using this feature.
Note: When using multiple VRFs, a default route must exist in the default VRF. If not, the Multiple VRF feature will not
function correctly.