432 APPENDIX D: 3COM XRN
DRR is an XRN-specific implementation that only operates on XRN within the
Distributed Fabric. However it will interoperate with other routers outside of the
XRN Distributed Fabric.
Figure 106 Network Example illustrating Distributed Resilient Routing
Distributed Link
Aggregation (DLA)
DLA ensures that all member ports of an aggregated link distribute the traffic flow
across the Distributed Fabric. This provides resilience and enhanced performance.
Failure in one of the member links in the Aggregated Link will not affect
communication to the Distributed Fabric as traffic will be forwarded via the
remaining member links. Distributed Link Aggregation Example
You can also use DLA to create highly resilient network backbones, supporting
multihomed links to the wiring closets as shown in
Figure 107.
Intelligent local forwarding ensures that each Switch in the XRN Distributed Fabric
forwards traffic to local Link Aggregation ports rather than across the Fabric
Interconnect, thereby reducing network traffic.
You can also use resilient links or STP/RSTP for resilience, however, this does not
provide the bandwidth advantage of link aggregation.
For more information about STP/RSTP refer to Chapter 5 “Network Protocol
Operation”.
VLAN1 VLAN 3VLAN 2
VLAN 3
VLAN 2VLAN 1
XRN Distributed
Fabric
Core Switches
Switch 5500 units
XRN Distributed
Fabric
R1 R2 R3
R1 R2 R3
R1 R2 R3
R1 R2 R3
To Next Page