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Spirent KB Article
Doc ID: FAQ18804
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Landslide: Can a TS be deployed remotely from a TAS?
Supporting (v)TS deployed in a remote geo-location from (v)TAS with increased latency and reduced reliability
FAQ current from version 17.6
Sometimes it is convenient or desired to deploy a Landslide Test Server in a separate geo-location (closer to DUT or where host server equipment exists) from a Test Administration Server that is already in use. While it is important for the management link between the TAS and TS be reliable with sufficient bandwidth there are features within Landslide to improve communication over less than perfect links.
During test execution, the TAS will reliably upload test configuration and download results at the start and stop of every test session using SSH/SFTP and has a one minute time out for these operations. It follows that the bandwidth necessary for the comm link then is variable and depends on the number of remote TS and how many test cases are running at the same time.
During a live test, status and heartbeat communication is done via UDP. This is also true for the initial TS registration. Messages are normally large and if they are segmented or fragmented and not arriving completely whole there will communication issues. The MTU's should be high enough across the network path to make sure this is avoided. There are two features within Landslide that can improve the reliability of this communication
During TS/TAS ipcfg phase, a TCP VPN can be enabled to carry control messaging which should prevent problems of UDP packets being lost/reordered/dropped. This does change the ports required for TAS Manager and Test Server messaging (8889-8897 for UDP, 1194 for TCP VPN)
Remote TS Control Messaging:
On a per test session basis in Test Session Settings drop-down menu, "Remote TS Control Messaging" feature can be enabled. Normally control messages are sent with the assumption they are received by TS and state is polled moving forward. On less reliable links, this feature can be used to cause the TAS to wait for an ACK from the TS for each control message sent and allow a retransmit of each command up to two times. This would have the expected side effect of causing tests to take a bit longer to start/stop than usual.
This feature is only available if activated first in the license (ts_reliable_msg)
Product : TAS Manager,Landslide Client