Designated Forwarder Election
The Designated Forwarder (DF) election mechanism is used to determine a designated forwarder in dual-homed
or multi-homed devices or networks. The election is performed on a per service basis. The DF filtering function
for MHN differs from that for MHD in:
• Directionality—DF filtering for MHN is applied for traffic both ingress and egress on the access-facing
Ethernet interfaces; whereas, DF filtering for MHD is applied only to traffic that egress the access-facing
interfaces.
• Traffic Type—DF filtering for MHN impacts both unicast as well as flooded multi-destination traffic;
whereas, DF filtering for MHD only applies to flooded multi-destination traffic.
The following figure shows the various DF filtering rules for MHN and MHD.
Figure 48: DF Filtering Comparison for MHN/MHD
Access Auto-Sensing
PEs connected to a multi-homed or dual-homed device may support active-active per flow also known as
flow-based load balancing. PE services CEs via physical or bundle ports. An Ethernet segment identifier is
assigned per port. This value is calculated from the connected CE using information such as, CE system
priority, CE system ID and CE port key. The PE must auto-detect the access topology to determine the type
of load balancing. The load balancing could be active-active per flow load-balancing, per service load-balancing
or simply no load balancing.
MMRP for PBB VPLS Flood Optimization
In a PBB network, traffic (unknown unicast, multicast, or broadcast) is flooded to all the PE devices in the
network even if the devices do not host the service instance to which the traffic is destined.
The Multiple MAC Registration Protocol (MMRP) for PBB VPLS Flood Optimization feature optimizes the
impact of the flooded traffic on PE devices by sending the traffic only to the PE devices interested in a particular
service instance.
L2VPN and Ethernet Services Configuration Guide for Cisco ASR 9000 Series Routers, IOS XR Release 6.3.x
366
Implementing IEEE 802.1ah Provider Backbone Bridge
MMRP for PBB VPLS Flood Optimization
To Next Page
Loading...
Need help?
General
