Forum Discussion
Sumanta_88744
Cirrus
CirrusCreating an active-active DSC configuration with OSPF routing on 11.x
Hi Experts
I have to do a deployment of active/active VIPRION 2400 chassis, running 2250 blades. As per below link, we need to create two traffic groups for each VLAN. How will the default routi...
Kevin_Davies_40
Nacreous
NacreousIn order to use active-active you must use SNAT. Then default routing does not come into play. The return address will be the server side floating IP address of whichever traffic group passed the traffic. The return path to the client will use auto-lasthop feature.
Each traffic group must have a unique floating IP address assigned to it. They can be consecutive addresses in the same subnet. When traffic passes through a VS using an virtual address assigned to a traffic group then address translation will use the floating IP address assigned to that traffic group as the SNAT address for traffic on the way to the servers.
Sumanta_88744Thanks Kevin, I was wondering how server pool would behave in case of two different VIPs (default gateway of the servers) in two Traffic Groups. Also, I was thinking if the F5 OSPF peer (both for upstream/downstream routers) has to be on self IP (part of local traffic group) or has to be on VIP in one of the floating traffic groups (traffic group - 1 or traffic group - 2)? As per doc, Active/active DSC mandates creation of more than one traffic groups and then shifting the second traffic group to be active on the F5 LB unit 2. So, shall we create the self IPs (running OSPF) and make it part of traffic groups or keep it as local traffic group only? In case of /30 segment, we can only create local traffic group (single self IP per LB). For floating traffic groups, we need /29 or more IP subnet for including self and the floating VIPs. The network design is such that both units receive traffic from OSPF neighbors. We also have VCMP enabled, if needed at all in this scenario. There is also the consideration of internal server pool having two gateways for 2 different TG.- Sumanta_88744Also, Kevin, SNAT can not be enabled since we need to preserve source IP information for logging purposes.
mimlo_61970Cumulonimbus
I believe Kevin is correct that you must use SNAT for active/active configurations. It is the only way to ensure the response traffic returns through the same LTM. If these are http/https websites, you can use the x-forwarded-for header to pass the original IP information to the server for logging purposes- Sumanta_88744thanx a lot. I still have doubts about keeping OSPF peer local to the self unit and not part of any floating traffic group.