The below config is referring a server-to-server load balance same
vlan.
The config is based on:
- csm routed mode
- server source address "natted" as soon as initiate session
- server source session pointing a Vserver to balanced again on the
same server farm
- two server farm has been defined one for each way of the session
The questions are?
- My I adopt the same configuration idea in a csm bridge mode?
- The server source session pointing a Vserver can balance again a
different server farm in a bridge mode implementation?
- Are there any drawbacks on a bridge mode implementation?
Any hel is appreciated.
Thanks.
Best regards, Fabio.
******************************************************
**** Server-to-server load balanced connections ******
****
same VLAN
******
******************************************************
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This example shows a CSM configuration to support
client and server originated connection to the same
virtual IP address, performing source NAT only on
server originated connections.
This configuration allows servers to originate
connections to a VIP, which will balance them back
to the same serverfarm, and eventually even to the
same server: source NAT takes care of redirecting
the return traffic back to the CSM
********* Relevant portions of the config ************
module ContentSwitchingModule 4
vlan 110 server
ip address 10.10.110.2 255.255.255.0
alias 10.10.110.1 255.255.255.0
!
vlan 111 client
ip address 10.10.111.5 255.255.255.0
gateway 10.10.111.1
!
natpool POOL-1 10.10.110.99 10.10.110.99 netmask 255.255.255.0
!
real SERVER1
address 10.10.110.10
inservice
real SERVER2
address 10.10.110.20
inservice
!
serverfarm FARM-A
nat server
no nat client
real name SERVER1
inservice
real name SERVER2
inservice
!
serverfarm FARM-B
nat server
nat client POOL-1
real name SERVER1
inservice
real name SERVER2
inservice
!
vserver EXTERNAL
virtual 10.10.111.100 tcp telnet
vlan 111
serverfarm FARM-A
persistent rebalance
inservice
!
vserver INTERNAL
virtual 10.10.111.100 tcp telnet
vlan 110
serverfarm FARM-B
persistent rebalance
inservice
!
********** Output of some show commands **************
Cat6k-1#sh
mod csm 4 arp
Internet Address Physical Interface VLAN
Type
Status
-------------------------------------------------------------------10.10.110.99
00-02-FC-E1-65-CF
0
CLNTNAT
local
10.10.111.100
00-02-FC-E1-65-CF
0
VSERVER
local
10.10.110.1
00-02-FC-E1-65-CF
110
-ALIASlocal
10.10.110.2
00-02-FC-E1-65-D0
110
--SLB-local
10.10.110.10
00-D0-B7-81-C1-AB
110
REAL
up(0 misses)
10.10.111.1
00-50-3E-9F-7C-0A
111
GATEWAY
up(0 misses)
10.10.111.5
00-02-FC-E1-65-D0
111
--SLB-local
10.10.110.20
00-D0-B7-81-C1-AB
110
REAL
up(0 misses)
Cat6k-1#
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At this point, we open a connection from a client 10.10.1.100
to the VIP. The connection is sent to server1 (10.10.110.10).
No source NAT is applied.
Then we open a connection from server1 to the same VIP.
In this case, it gets balanced to server2.
Cat6k-1#show
mod csm 4 real
real
server farm
weight state
conns/hits
-----------------------------------------------------------------------SERVER1
FARM-A
8
OPERATIONAL
1
SERVER2
FARM-A
8
OPERATIONAL
0
SERVER1
FARM-B
8
OPERATIONAL
0
SERVER2
FARM-B
8
OPERATIONAL
1
Cat6k-1#show
mod csm 4 conn deta
prot vlan source
destination
state
---------------------------------------------------------------------In TCP 111 10.10.1.100:34014
10.10.111.100:23
ESTAB
Out TCP 110 10.10.110.10:23
10.10.1.100:34014
ESTAB
vs = EXTERNAL, ftp = No, csrp = False
In TCP 110 10.10.110.10:32947
10.10.111.100:23
Out TCP 110 10.10.110.20:23
10.10.110.99:8192
vs = INTERNAL, ftp = No, csrp = False
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ESTAB
ESTAB
Note that the first connection comes in from VLAN 111 and is sent
out on VLAN 110, while the second connection comes in and goes out
on the same VLAN.
The second connection is also source NAT'ed using the unique IP
configured in the NAT pool (the NAT pool could have multiple IP
addresses, if needed - keep in mind that a single IP can support
up to 56k concurrent connections)
Cat6k-1#show mod csm 4 vser detail
EXTERNAL, type = SLB, state = OPERATIONAL, v_index = 10
virtual = 10.10.111.100/32:23 bidir, TCP, service = NONE, advertise =
FALSE
idle = 3600, replicate csrp = none, vlan = 111, pending = 30, layer 4
max parse len = 2000, persist rebalance = TRUE
ssl sticky offset = 0, length = 32
conns = 1, total conns = 1
Default policy:
server farm = FARM-A, backup = <not assigned>
sticky: timer = 0, subnet = 0.0.0.0, group id = 0
Policy
Tot matches Client pkts Server pkts
----------------------------------------------------(default)
1
167
116
INTERNAL, type = SLB, state = OPERATIONAL, v_index = 11
virtual = 10.10.111.100/32:23 bidir, TCP, service = NONE, advertise =
FALSE
idle = 3600, replicate csrp = none, vlan = 110, pending = 30, layer 4
max parse len = 2000, persist rebalance = TRUE
ssl sticky offset = 0, length = 32
conns = 1, total conns = 1
Default policy:
server farm = FARM-B, backup = <not assigned>
sticky: timer = 0, subnet = 0.0.0.0, group id = 0
Policy
Tot matches Client pkts Server pkts
----------------------------------------------------(default)
1
46
35
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Now, we close the server-originated connection and we open a new
one, which now gets balanced back to the same server1
Also in this case, there are no problems, since source NAT is
enabled and masks the original source IP of the requester so
the server does not know that it's "talking with itself".
Cat6k-1#show
mod csm 4 real
real
server farm
weight state
conns/hits
-----------------------------------------------------------------------SERVER1
FARM-A
8
OPERATIONAL
1
SERVER2
FARM-A
8
OPERATIONAL
0
SERVER1
FARM-B
8
OPERATIONAL
1
SERVER2
FARM-B
8
OPERATIONAL
0
Cat6k-1#
Cat6k-1#
Cat6k-1#
Cat6k-1#show mod csm 4 conn deta
prot vlan source
destination
state
---------------------------------------------------------------------In TCP 111 10.10.1.100:34014
10.10.111.100:23
ESTAB
Out TCP 110 10.10.110.10:23
10.10.1.100:34014
ESTAB
vs = EXTERNAL, ftp = No, csrp = False
In TCP 110 10.10.110.10:32946
10.10.111.100:23
Out TCP 110 10.10.110.10:23
10.10.110.99:8193
vs = INTERNAL, ftp = No, csrp = False
ESTAB
ESTAB