Network Example using XRN 679
Figure180 A Dual XRN Distributed Fabric Network
How to Set up this Network
This section provides information on how to configure an XRN network as shown
in Figure 180. It assumes you have carried out step 1 to step 4 as detailed in “How
to Implement XRN—Overview” on page 676.
1Enable LACP on the required ports, ensuring you have not connected your devices
to the Distributed Fabric yet as you must configure your VLANs before the
aggregated links are configured. Individual port members of each aggregated link
must have VLAN membership explicitly set, that is, manually configured, before
the aggregated link is set up. You must not rely on port members inheriting VLAN
membership configuration from the aggregated link.
2Create the VLANs and assign VLAN membership to all ports.
3Connect up your ports. As LACP was enabled in step 1 the aggregated links will
now automatically configure themselves.
4Configure the router IP interfaces.
5Ensure that RSTP is enabled across the network.
Legacy aggregated links are not resilient to an interconnect failure. Hence the
3Com recommendation to use IEEE 802.3ad aggregated links (LACP) for maximum
resilience.
If an automatic aggregated link (created by LACP) contains ports with different
VLAN membership, the aggregated link will inherit the VLAN membership of the
first port that comes up in the aggregated link. It will override any pre-defined
VLAN membership for the aggregated link.
VLAN2
VLAN1
VLAN2
VLAN1
Switch5500 units
XRNDistributed Fabric
Servers on
1000 Mbps connections
802.3ad
AggregatedLinks
VLANID1, 2 VLANID1, 2 VLANID1, 2 VLANID1, 2
XRNDistributed Fabric