BES Server and Network Latency

Below article has been taken from RIM website explaining the latency and its side effects to the Exchange server. We will also attaching to this e-mail official RIM document "Capacity Planning and Performance Tuning for Environments Using the BlackBerry Enterprise Solution".

Pinging nhqbes1.SMTp25.net [10.160.10.112] with 32 bytes of data:

Reply from 10.160.10.112: bytes=32 time=358ms TTL=124

Reply from 10.160.10.112: bytes=32 time=328ms TTL=124

Reply from 10.160.10.112: bytes=32 time=358ms TTL=124

Reply from 10.160.10.112: bytes=32 time=345ms TTL=124

Reply from 10.160.10.112: bytes=32 time=367ms TTL=124

Reply from 10.160.10.112: bytes=32 time=362ms TTL=124

Reply from 10.160.10.112: bytes=32 time=372ms TTL=124

Reply from 10.160.10.112: bytes=32 time=426ms TTL=124

Reply from 10.160.10.112: bytes=32 time=354ms TTL=124

Reply from 10.160.10.112: bytes=32 time=357ms TTL=124

Reply from 10.160.10.112: bytes=32 time=205ms TTL=124

Ping statistics for 10.160.10.112:

Packets: Sent = 11, Received = 11, Lost = 0 (0% loss),

Approximate round trip times in milli-seconds:

Minimum = 205ms, Maximum =  426ms, Average =  348ms

When latency between the BlackBerry Enterprise Server and the Microsoft Exchange Server increases, the number of factors that may impede the successful delivery of UDP notifications increases as well. Increased latency lengthens the time required for data transfer--which uses TCP/IP--between applications, for instance, the higher the latency between the BlackBerry Enterprise Server and the Microsoft Exchange Server, the longer it takes for data to travel between them. The increased data transfer time is relational to the latency of the WAN connection, and not necessarily its bandwidth. This is because TCP acknowledgements take longer to be sent if network latency exists, which delays the occurrence of the next data transfer.

If latency exists between the BlackBerry Enterprise Server and the Microsoft Exchange Server, it is expected that latency exists in the messaging environment. To help achieve optimal BlackBerry Enterprise Server performance, refer to the recommendations made in the Capacity Planning and Performance Tuning for Environments Using the BlackBerry Enterprise Solution document.

Problem:

users are having interruption on their BlackBerry devices. Blackberry users are not getting mail on their hand due to high latency on the network.

Root Cause:

The Current bandwidth seems to be the bottleneck at this point. The extended ping fluctuates dramatically, which indicates the pipe/bandwidth problem from site Exchange server to the national BES server. The connections also are not stable since it spikes at all the times.

• Overall picture how BES will work when a user receives a message:
  
• BES servers will open several worker treats similar to MAPI connections to the Exchange mailbox server to scan the new mails, upon arriving into each BES users mailboxes. Worker treats will pull these mails back to BES servers and push it to RIM facility, and RIM finally will let wireless ISP to deliver these to the handhelds
  

The latency is indentified by BES support is fact and worker treats to get hang and resulting similar issues is addressed on their best practices.

Identifying latency as root cause:

We have created test account on Local exchange server, reside within the same data canter as BES servers and asked Client to activate his Black berry by using this account. The account was successfully activated and Client was able to send and receive mails by using his black Berry

• This shows us clearly the latency was the bottleneck.
  

Recommended Solution:

• RIM recommends centralized architecture when it is possible. RIM also advices to make sure the latency is less than 35 millisecond between the black Berry server and the mailbox server. SMTP25 Exchange Team also recommends centralizing all mailbox servers along with Black Berry server to prevent such problems happening in the future.
  

Best regards,

Oz Ozugurlu