H3C Technologies H3C SecBlade LB Cards - Manual (Page 35)

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Item Description
Persistence Method
Select a method for associating real services and connections that access the
same virtual service.
Using a persistence method can reduce the number of times for an LB product to
distribute services and traffic.
• If you do not select any method, no association is performed.
• Cookie Insert—If no Set-Cookie field with server information is carried in a
response sent by the server, the LB product adds a Set-Cookie field including
server information. Then the client will carry the Cookie field that contains the
server information in the next request. LB product will match the Cookie
information, and then select a corresponding real server to send the request
to it.
• Cookie Get—The response sent by the server carries the Set-Cookie
information. The LB product gets the Cookie value in the response according
to the user-configured Cookie ID. For the subsequent packets sent by the
client, if the packets match the cached Cookie value, the LB product sends the
packets to the corresponding real service.
• Cookie Rewrite—If the response sent by the server carries the Set-Cookie
field that contains the H3C-SrvID=xxxxxxxx character string, the LB product
replaces the "xxxxxxxx" character string in the Set-Cookie field with the
server information. Then the client will carry the Cookie field that contains the
server information in the next request, and the LB product will sends the
request to the corresponding real service according to the server information
in the Cookie field. Cookie Rewrite improves the Cookie Insert mode.
• SIP—Keeps sessions according to the Call-ID in a SIP packet. SIP connection
over TCP/UDP is supported.
• HTTP Header—Keeps sessions according to the HTTP header information.
• SSL—Keeps sessions according to the Session ID of the SSL protocol packets.
• RADIUS—Keeps sessions according to the RADIUS attributes
(Framed-IP-Address or User-Name).
• DHCP—Keeps sessions according to the DHCP attributes (Transaction ID or
Client Hardware Address).
IMPORTANT:
• If you select TCP as the protocol, the Cookie Insert, Cookie Get, Cookie
Rewrite, SIP, HTTP Header, and SSL persistence methods are supported. If
you select UDP as the protocol, the RADIUS, SIP, and DHCP persistence
methods are supported.
• If you select RTSP URL as the real service group method, set the persistence
method to none. Otherwise, load balancing cannot work properly.
• If you adopt the Cookie Rewrite method, you need to configure
H3C-SrvID=xxxxxxxx on the server, and the length of xxxxxxxx depends on
the aging time configured on the LB product. If the aging time is Session Age,
the length of xxxxxxxx cannot be smaller than 8 bytes. If you manually set the
aging time, the length of xxxxxxxx cannot be smaller than 47 bytes.
Otherwise, Cookie Rewrite performance will be greatly reduced.
• If you adopt the Cookie Insert method, H3C recommends that you reduce the
TCP MSS value (maximum segment size for TCP) by 40 bytes for the
interfaces on the network path between the LB product and the client.
Otherwise, TCP fragments might be too large to be processed by the client.
For more information about TCP MSS configuration, see Network
Management Configuration Guide or System Maintenance Configuration
Guide.