Implementing IBM System Networking 10Gb Ethernet Switches

80 Implementing IBM System Networking 10Gb Ethernet Switches

You may select a physical port, static trunk, or an LACP adminkey as a Hot Link interface.

Forward Delay

The Forward Delay timer allows Hot Links to monitor the Master and Backup interfaces for

link stability before selecting one interface to change to the active state. Before the transition

occurs, the interface must maintain a stable link for the duration of the Forward Delay interval.

For example, if you set the Forward Delay timer to 10 seconds, the switch selects an interface

to become active only if a link remains stable for the duration of the Forward Delay period. If

the link is unstable, the Forward Delay period starts again.

Preemption

You can configure the Master interface to resume the active state whenever it becomes

available. With Hot Links preemption enabled, the Master interface transitions to the active

state immediately upon recovery. The Backup interface immediately changes to the standby

state. If Forward Delay is enabled, the transition occurs when an interface maintains link

stability for the duration of the Forward Delay period.

FDB update

Use the FDB update option to notify other devices on the network about updates to the

Forwarding Database (FDB). When you enable FDB update, the switch multicasts addresses

in the FDB over the active interface, so that other devices on the network can learn the new

path. The Hot Links FBD update option uses the station update rate to determine the rate at

which to send FDB packets.

2.7.4 Fast Uplink Convergence

Fast Uplink Convergence enables IBM System Networking switches to quickly recover from

the failure of the primary link or trunk group in a Layer 2 network using STP/PVST+ mode.

Normal recovery can take up to 50 seconds, while the backup link transitions from Spanning

Tree Blocking to Listening to Learning and then Forwarding states. With Fast Uplink

Convergence enabled, the IBM System Networking switch immediately places the secondary

path into Forwarding state, and multicasts the addresses in the FDB and ARP table over the

secondary link so that upstream switches can learn the new path.

2.7.5 NIC teaming and Layer 2 failover

The primary application for Layer 2 Failover is to support Network Adapter Teaming. With

Network Adapter Teaming, all the NICs on each server share an IP address, and are

configured into a team. One NIC is the primary link, and the other is a standby link. For more

details, see the documentation for your Ethernet adapter.

Failover: Only two links per server can be used for Layer 2 Trunk Failover (one primary

and one backup). Network Adapter Teaming allows only one backup NIC for each

server blade.