ServerIron ADX Server Load Balancing Guide
Release 12.0.00
June 15, 2009

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Server Load Balancing > Source-Port Based BP Distribution

Source-Port Based BP Distribution
This feature provides additional flexibility for traffic distribution across the Barrell Processors (BP). It helps achieve even distribution across all BPs, even if client traffic is originated from proxy server or fewer source IP addresses.
You can select this method of barrell distribution as an option to the existing default method.
This feature contains the following sections:
Configuring Source-Port Based BP Distribution
To enable this feature use the following command:
ServerIron(config)# server jc-source-port-hash
NOTE:  
 
Limitations
Source-Port Based BP Distribution has the following limitations:
This feature does not support combinations such as SLB + IP NAT and SLB + TRL.
System with Single Management Module
 
Value of the four least significant bits of source port in Hexadecimal

1
BP#1 refers to BP1 on active M6/M7.

2
BP#1 and BP#2 refer to BP1 and BP2 on M6/M7 respectively.

3
BP#1, BP#2 and BP#3 refer to BP1, BP2 & BP3 on M6/M7 respectively.

For 1-BP M6/M7, source port hashing results in 100% of the traffic going to the single BP in the system.
For a 2-BP M6/M7, source port hashing results in 50% of traffic to each of the BPs.
For a 3-BP M6/M7, source port hashing results in BP1 receiving 37.5% of the traffic, and BP2 and BP3 each receive 31.25% of the traffic. This assumes that the traffic is received from contiguous source ports.
On the reverse direction, traffic is hashed based on destination ports. Note that there are 4 more bits of destination port used in the hashing but that will not affect the distribution. This is the exact scheme we use in source IP hashing.
System with Dual Management Modules
 
Value of the four least significant bits of source port in Hexadecimal

1
BP#1 refers to BP1 on active M6/M7.

2
BP#1 and BP#2 refer to BP1 and BP2 on M6/M7 respectively.

3
BP#1, BP#2 and BP#3 refer to BP1, BP2 & BP3 on M6/M7 respectively.

For 1-BP M6/M7, source port hashing results in 50% of the traffic going to the BP on the active module and 50% of the traffic going to the BP on the secondary module.
For 2-BP M6/M7, source port hashing results in 25% of the traffic going to each of the 2 BPs on the active module and each of the 2 BPs on the secondary module.
For a 3-BP M6/M7, source port hashing results in 18.75% of the traffic going to each BP of the active management module. On the secondary management module, BP1 receives 18.75% of the traffic, while BP2 and BP3 receive 12.5% of the traffic. This assumes that the traffic is received from contiguous source ports.

Server Load Balancing > Source-Port Based BP Distribution

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