09-20-2011 04:21 AM
Multi-hosted IP addresses allow the same traffic IP to be hosted on several traffic managers at the same time. This can provide benefits to traffic distribution and reduce the number of IPs needed to run a service. For more background, check out the article Feature Brief: Deep-dive on Multi-Hosted IP addresses in Stingray Traffic Manager.
Multi-hosted IPs make use of multicast messages that are broadcast by each traffic manager. These messages are received by network switches and routers to let them know where to send network packets for these IP addresses. Most switches and routers should work perfectly without any additional configuration, however sometimes you may need to tweak some settings on a switch. If you cannot contact a multi-hosted IP, first try pinging the IP in question from a machine on the same subnet as the traffic manager, and then from a machine outside of the subnet. If these ping packets are not replied to, you may need to reconfigure your switches.
Cisco Catalyst switches using the IOS software, need to be manually told about each Multi-Hosted IP's multicast MAC address, which is used to deliver the IP's incoming connections to all machines in the Traffic IP group. This can be done by logging into the CLI of the switch and using the following commands:
For each Multi-Hosted IP in the Traffic IP group:
arp [Multi-Hosted IP] [MAC]
Then, for Cisco Catalyst 6000/6500 series switches:
mac-address-table static [MAC] interface [Interfaces] disable-snooping
Or for all other Catalyst switches:
mac-address-table static [MAC] interface [Interfaces]
Replace [MAC] with the MAC address listed on the Edit Traffic IP Groups page, and [Interfaces] with the interfaces on the switch connected to the Stingray cluster. Refer to Cisco's documentation for details.
Please consult the documentation for your switch hardware, particularly any information regarding broadcast MAC addresses or multicast. When configuring the switch, you may need to take a note of the MAC address used for each multi-hosted IP. This information is shown on the Edit Traffic IP Groups page.