Brocade Communications Systems 12.4.00 Manual De Usuario

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ServerIron ADX Global Server Load Balancing Guide
53-1002437-01
Round-trip times
1
In the example above, assume that the GSLB ServerIron ADX is configured as Mode 2. Also assume 
that this GSLB ServerIron ADX is providing GSLB for www.foo.com where the IP addresses for this 
domain are IP-1, IP-2, and IP-3. IP-1 is a VIP on ServerIron ADX-1. IP-2 is a VIP on ServerIron ADX-2. 
IP-3 is a VIP on ServerIron ADX-3. 
If a DNS resolution request comes from LDNS 201.53.10.1, then GSLB ServerIron ADX uses only 
the RTT information for IP-1 which is configured on ServerIron ADX 1.1.1.102 (rtt = 7ms, source = 
active). Since the GSLB ServerIron ADX in configured as Mode 2, only actively reported RTT values 
are used during the selection. The RTTs for IP-2 and IP-3 are not used since the source of these 
RTTs is passive.
The RTT algorithm mode can be configured globally in a global GSLB policy or locally in a host-level 
GSLB policy. Placing the modes in different policies allows you to use different RTT algorithm 
modes for different hosts. The default RTT algorithm mode for a global or host level GSLB policy is 
Mode 1. 
Using only passive RTT
To configure a global GSLB policy to use only passive RTT values for RTT algorithm (Mode 1), enter 
commands such as the following:
GSLB-ServerIronADX# configure terminal 
GSLB_ServerIronADX(config)# gslb policy
GSLB-ServerIronADX(config-gslb-policy)# round-trip-time active-rtt 
use-passive-rtts-only      
To configure a host-level GSLB policy to use only passive RTT values for RTT algorithm (Mode 1), 
enter commands such as the following:
GSLB-ServerIronADX# configure terminal
GSLB-ServerIronADX(config)# gslb-host-policy test
GSLB-ServerIronADX(config-gslb-host-policy-test)# round-trip-time active-rtt 
use-passive-rtts-only  
Syntax: round-trip-time active-rtt use-passive-rtts-only     
Using only active RTT
To configure a global GSLB policy to use only active RTT values for RTT algorithm (Mode 2), enter 
commands such as the following:
GSLB-ServerIronADX# configure terminal
GSLB_ServerIronADX(config)# gslb policy
GSLB-ServerIronADX(config-gslb-policy)# round-trip-time active-rtt 
use-active-rtts-only  
To configure a host-level GSLB policy to use only active RTT values for RTT algorithm (Mode 2), 
enter commands such as the following:
GSLB-ServerIronADX# configure terminal
GSLB-ServerIronADX(config)# gslb-host-policy test
GSLB-ServerIronADX(config-gslb-host-policy-test)# round-trip-time active-rtt 
use-active-rtts-only         
Syntax: round-trip-time active-rtt use-active-rtts-only 
Using both active and passive RTT
To configure a global GSLB policy to use both passive and active RTT values for RTT algorithm 
(Mode 3), enter commands such as the following: