Split Trunking Support with HP Auto Port Aggregation

# nwmgr -g -S apa

Class Mode Load Speed- Membership

Instance Balancing Duplex

======== =========== ========= ==================== ===========================

lan900 LACP_AUTO LB_MAC 400 Mbps Full Duplex 9,10,11,12

lan901 Not_Enabled LB_MAC 0 Mbps -

lan902 Not_Enabled LB_MAC 0 Mbps -

lan903 Not_Enabled LB_MAC 0 Mbps -

lan904 Not_Enabled LB_MAC 0 Mbps -

Removing the LACP Aggregation on the Switches

To remove the LACP aggregation on the switches, disable LACP on all the ports added to the SMLT.

So on each switch, disable LACP on ports 2/31 and 2/32. Then delete the MLT-31. So on each

switch, enter the following commands:.

# conf ether 2/31-2/32 lacp disable

# conf mlt 31 delete

Removing the IST on the Switches

In order to remove an IST, you must first disable it. Then, delete the IST from the MLT and remove the

MLT. Enter the following commands on each switch:

# conf mlt 21 ist disable

# conf mlt 21 ist delete

# conf mlt 21 delete

Example: Create a SMLT Trunk in Manual Mode

To create an SMLT trunk running in Manual mode using the same ports as the previous example, you

must first create the IST. See the example on creating the LACP SMLT link aggregation to do that.

Then, create the SMLT trunk by entering the following commands on each switch:

Switch# conf mlt 31 create

Switch# conf mlt 31 add ports 2/31-2/32

Switch# conf mlt 31 smlt create smlt-id 31

On the server side, create the Manual mode link aggregation using the nwmgr command (available

only on HP-UX 11i v3) as follows:

# nwmgr –a –A mode=MANUAL –A links=9,10,11,12 –c lan900

Conclusion

Currently both Nortel SMLT and Cisco switches support LACP and Manual type split trunks.

When you can use switches configured for SMLT or stacking, HP recommends that you use a split

LACP link aggregation to provide a highly available link aggregation. In addition, this solution is also

an active-active failover solution as each member ports bandwidth can carry traffic. When switch

failure occurs, the link aggregation remains available but its bandwidth capability is reduced.

A split LACP link aggregation is preferred over a split Manual mode link aggregation. The Manual

mode link aggregations cannot handle switch failures. As a result, ports connected to the bad switch

might still be part of the link aggregation. This can cause traffic to be transmitted on the bad switch

ports, and might be dropped as a result. With the LACP protocol, ports connected to failed switches

are dropped from the LACP link aggregations. Consequently, traffic losses are eliminated.

If you do not have switches that can be configured to utilize SMLT or cross-stack EtherChannels, you

can still have the capability for a highly available network link by using a failover group of link