Brocade Communications Systems ServerIron ADX 12.4.00 - Manual (Page 237)

ServerIron ADX Global Server Load Balancing Guide 225
53-1002437-01
Advanced GSLB configuration for IPv6
2
High availability considerations for IPv6 sticky persistence
Sticky GSLB enables the GSLB controller to return the same IP address if a client sends multiple
DNS requests within a configurable period of time.
Controllers, when configured in HA scenarios, will need to sync their sticky sessions in order to
maintain persistence across the controllers. This is similar to the IPV4 sticky persistence behavior.
IPV4 and IPV6 sticky sessions will share the same special signature. All sticky GSLB ipv6 sessions
are identified by the client IP and the following three tuples that remain the same for all sticky
sessions:
• Dst-IP - 255.0.255.0
• S-port – 7
• D-port – 8
ServerIronADX(config)# show session all 0
Session Info:
Flags - 0:UDP, 1:TCP, 2:IP, 3:INT, 4:INVD, H: sessInHash, N: sessInNextEntry
Index Src-IP Dst-IP S-port
D-port Age Next Serv Flags
===== ====== ====== ====== ======
=== ==== ==== ======
0 0.0.0.5 100.1.1.10 5 80
0 000000 n/a SLB1 H
1 0.0.0.5 100.1.1.30 5 80
0 000000 n/a SLB1 H
2 2001:0DB8::78 255.0.255.0 7 8
57 000000 n/a SLB3 H
3 100.1.1.0 255.0.255.0 7 8
57 000000 n/a SLB3 H
In the example, the second and third rows show IPV6 and IPV4 sticky sessions.
Hash-based persistence for IPv6
GSLB ServerIron ADX offers two methods for site persistence: sticky persistence and hash-based
persistence.
Hash-based persistence is the best solution for site persistence in environments that utilize two
GSLB controllers (not in an HA configuration) for the same domain and where site persistence is
needed for a single client that is directed to those GSLB controllers. When users query for a host
name, they receive the same IP address for that domain regardless of which GSLB controller is
contacted.
Sticky persistence alone is sufficient for single-box and High Availability (hot standby, symmetric
active-standby, symmetric active-active) topologies. For more information, see
“Sticky persistence
for IPv6” on page 222.
Specifying hash-based persistence prefix lengths
By default, the ServerIron ADX does hash-based GSLB persistence for every IPv6 DNS client with a
prefix length of 128 bits. The ipv6-prefix-len-hash-persist parameter enables you to specify an
alternative prefix length.