OpenClovis Product Documentation

Revision as of 06:08, 6 June 2012

TIPC Configuration

Overview

OpenClovis uses the TIPC [[1]] Linux kernel module to provide low latency communications between nodes in the cluster. However, as configured out-of-the-box, TIPC sometimes has trouble handling the bandwidth required for telecom applications.

This can result in link "flapping" (several rapid link-level drops and reconnects) or dropped packets.

FAQ

• How can the TIPC configuration be changed to support higher bandwidth?

You need to recompile the TIPC module. Directions on compiling kernel modules are all over the internet so shall not be repeated here. Increase/modify the following macros in the tipc source code before recompiling tipc module:

• TIPC_DEF_LINK_WIN

to 250

in include/net/tipc/tipc_bearer.h

• TIPC_MAX_LINK_WIN

to 300

in include/net/tipc/tipc_bearer.h

• BCLINK_WIN_DEFAULT

to 150 (from 20)

in net/tipc/bcast.c

Optional and nice to have in case receiver/machine is running slow to avoid packet drops from tipc (flow control)

• OVERLOAD_LIMIT_BASE.

Change the default from 5000 to say 8000 (some tweaking may be necessary based on the difference in performance of your machines)

in net/tipc/socket.c

• TIPC_FLOW_CONTROL_WIN

from 512 to say 3000

in include/net/tipc/tipc_port.h

This will also alleviate the condition for the reliable or SOCK_STREAM tipc topology notification socket which can also be impacted.

Make sure that TIPC_FLOW_CONTROL_WIN*2 <= OVERLOAD_LIMIT_BASE

Then recompile and after reloading tipc and establishing both the links, confirm link window shows 250 instead of the default of 50 with tipc-config -ls=<link-name>

UDP configuration

Switch_your_model/image_from_TIPC_to_UDP