Technical data

DATA CENTER and CAMPUS NETWORKS DEPLOYMENT GUIDE
Deploying Brocade Networks with Microsoft Lync Server 2010 27 of 52
• Configure VLAN 999, used for the sync connection between the hardware load balancer switches. Note
that you must turn off Spanning Tree.
Hardware load balance (config)# vlan 999
Hardware load balance (config)# untagged ethernet 1
Hardware load balance (config)# no spanning-tree
• To set the number of minutes that the primary hardware load balancer waits before retaking over the
primary role after an outage, enter the following command (only on the primary hardware load
balancer; 5 minutes is the minimum value):
Hardware load balance# server backup-preference 5
• To save the configuration to NVRAM, enter the following command:
Hardware load balance# write memory
Setting Up Active-Standby VIP Redundancy
The configuration uses an active and standby VIP for each VIP created. The active VIP and backup VIP are
determined by the sym-priority value associated with the VIP. The VIP with the highest sym-priority value is
considered the active VIP, and the others are considered standbys. The configuration does not require any changes
to Spanning Tree and does not require any sync connection between the hardware load balancer, as it uses the
network topology. Note that there cannot be a router hop between the two hardware load balancer switches, and
there must be Layer 2 connectivity.
The minimum configuration for Active VIP is as follows. Configure the VIP to use sym-priority:
Hardware load balance1 (config)# server virtual vip1 1.1.1.1
Hardware load balance1 (config)# sym-priority 10
The minimum configuration for Standby VIP is:
Hardware load balance2 (config)# server virtual vip1 1.1.1.1
Hardware load balance2 (config)# sym-priority 5
Setting Up Active-Active Redundancy
Active-active SLB uses session information to ensure that the same hardware load balancer load balances all
requests for a given VIP. The first hardware load balancer that receives a request for the VIP load balances the
request, creates a session table entry for the VIP, and sends the session information to the other hardware load
balancer. Both hardware load balancer switches in the configuration use the session information, so that the same
hardware load balancer is used for subsequent requests for the VIP.
In this example, hardware load balancer A and hardware load balancer B each have been configured to provide
active-active Symmetrical Server Load Balancing (SSLB) for the HTTP port on VIP1 and VIP2. The first hardware load
balancer to receive a request for an HTTP port on one of these VIPs load balances the request, creates session
entries for the VIP, and sends the session information to the other hardware load balancer. Both hardware load
balancer switches use the session information for the VIP to ensure that the same hardware load balancer load
balances subsequent requests for the same application port and VIP.
Either hardware load balancer can use session information to forward the server reply back to the client. For
example, if hardware load balancer A is the load balancer for a client request, and the server reply comes back
through hardware load balancer B, hardware load balancer B can use the session information received from
hardware load balancer A, through session synchronization, to perform the required address translations and send
the reply to the client. Hardware load balancer B does not need to forward the reply to hardware load balancer A for
address translation and forwarding.