CSM(content switching module) supports the 2 tier server load balance ?

[mishao]

hi everyone,

Does any know the CSM support 2 tier server load balance ?

this means that CSM perform the server load balance for servers and the same servers require another time Server load balance. In the other word,

the CSM supports server port and client port for server load balance ?

thanks

fred.

[Gilles Dufour]

if you mean that you need a device that do the loadbalancing based on the source port, than the CSM does not do it.

If you want a device that can NAT both source port and destination port, than yes, the same does it.

[mishao]

I mean the servers behind CSM reqires to query other servers. eg. Clinet sends a query to CSM and send to servers behind CSM then the servers require to do another query to other servers. the same port on CSM do server load balance and client query.

[shamilton-wilkes]

As long as the client servers are on a different VLAN than the destination servers this will work fine. Stop thinking in ports - the CSM has none, think VLANs.

We've broken our servers up into functional groups, then we load balance public clients - public servers, and public servers - all the various other servers they contact.

Does this answer your question ?

[0gbalogh]

Is on the cisco site smaple configuration for this topology ?

[testas]

Hi, this seems to describe a typical case of multi-tier design where the CSM needs to handle 2 types of connections:

1. clients->CSM->serverfarm1

2. serverfarm1->CSM->serverfarm2

We usually refer to the second type of connections as server-to-server load balanced traffic.

There is no problem in handling that scenario with the CSM and you have a few options.

In particular, each virtual server on the CSM can be configured to only accept incoming connections from a specific VLAN, so you can use that as an additional security measure or to distinguish connections based on which VLAN they come in from.

If you want to, you could even configure the CSM with 2 virtual servers with the same exact virtual IP and L4 port, but listening on 2 separate VLANs (the client-side VLAN and serverfarm1 VLAN) and use a different server farm based on that.

One important thing to keep in mind when handling server-to-server load balanced connections: if serverfarm1 and serverfarm2 are on the same VLAN, you have to configure "client NAT" for the server-to-server connections, to force the return traffic back to the CSM.