Technical data

6 ServerIron ADX Advanced Server Load Balancing Guide
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SIP SLB and call persistence using ServerIron ADX
1
SIP SLB and call persistence using ServerIron ADX
Figure 2 shows an overview of a ServerIron ADX SIP server load balancing implementation.
FIGURE 2 ServerIron ADX SIP Server Load Balancing implementation
There are three kinds of SIP servers:
• Proxy server
• Redirect server
• Registrar server
In Figure 2, the ServerIron ADX SIP SLB uses the Domain-1 VIP to load balance SIP requests from
Client A (user1) or Client B (user2) among Domain 1 proxy servers and registrar servers.
The SIP Server Load Balancing uses the Domain-2 VIP to load balance SIP requests from Client A
(user1) or Client B (user2) among Domain 2 proxy servers and registrar servers.
The ServerIron ADX offers support for the following SIP servers in accordance with RFC 3261:
• Proxy
• Redirect
• Registrar
The ServerIron ADX supports the following methods in accordance with RFC 3261:
• INVITE
• REGISTER
• ACK
ServerIron
From/To SIP Phone To/From VIP
L2/3
Infrastructure
INVITE F2
SIP
Proxy
Server
INVITE F1
RINGING F4
OK F6
TRYING F3
RINGING F5
OK F7
RINGING F4
OK F6
INVITE F2
TRYING F3
RINGING F5
OK F7
INVITE F1
User 2
User 1
ACK F8
MEDIA RTP
BYE F9 OK F10