User`s manual

LOLA: Low Latency Audio Visual Streaming System
Appendix F – Known Issues
F.1 No timeout on remote partner unexpected disconnection
In some rare occasions, if the remote LOLA system occurs in an unexpected disconnection (system
or application problems, network disconnection, etc) and thus cannot notify the other system about its
closure, the local system remains “open and active” without warning (you of course immediately see you are
not receiving any more audio/video from the remote system). In such a case, just quit LOLA manually and
restart it to be ready for a new connection. If the remote system resumes transmission without requesting a
new “connect” (for example because it has been a network disconnection problem), both LOLA systems will
realign and restart normal operations without any action needed by you on both sides.
F.2 Windows Firewall and LOLA initial “check”
Windows 7 Firewall by default completely blocks ICMP (“ping”) packets. This makes the initial
LOLA “check” function unable to work correctly. To ensure that you can correctly use LOLA, without
risking to run with a Firewall completely disabled (if you are on the public Internet), you should configure
Windows Firewall with a rule enabling ICMP packets flow on your system (as well as on the remote system,
of course).
F.3 LOLA and antivirus software
LOLA uses an IP network packets building engine based on WinPcap libraries. Many antivirus
packages will detect this and list LOLA as a “malicious” software and try to block it. Until these antivirus
software will correctly recognize LOLA, you should disable them on your system. More over, in any case,
antivirus packages perform highly invasive activities on your PC, which can seriously compromise system
performances and LOLA itself. Thus you should carefully disable them while using LOLA.
F.4 Packet Per Second (PPS) and LAN Switches
LOLA produces a very high UDP packet per second (PPS) rate, especially when in color mode at
60fps. A number of LAN switches might be unable to cope with such a traffic, especially if there are other
applications running on the same switch which also requires a high PPS rate or packets priority handling
(like VoIP system/telephones, etc). If you see, for example via TaskMGR “network monitoring” application a
very irregular traffic pattern (and you get audio/video drops, clicks, artifacts), try to disable other
applications running on the same switches, or try to setup a direct connection between the LOLA system and
your border router, avoiding the LAN switches which cause the problem.
F.5 Packet Per Second (PPS) and NICs
Network Interface Cards (NICs) based on Realtek, Broadcom and some on Maverick chipset cannot
deliver correctly the PPS rate required by LOLA. This issue is know also when these NICs are used for other
kind of applications and depends on the the way the NIC drivers are handling traffic. There is no workaround
to this issue until the manufacturer fix it either in the NIC itself of the drivers. We suggest to use Intel based
NICs which work fine. Please see some important informations about “Interrupt moderation rate” settings for