On the Multicast updates tab, you can configure updates transmission on workstations via the multicast protocol.
Set the Enable multicast updates flag to enable transmission of updates to stations via the multicast protocol.
General principles of multicast updates:
1.If multicast updates are enabled, when for all stations connected to this Dr.Web Server updating is performed in two stages:
a)Stations are listening the specified multicast groups into which Dr.Web Server is included. When multicast updates are ready, stations download them via multicast over UDP.
b)After multicast updates are transmitted, Dr.Web Server sends standard notification to stations about updates to get. All that failed to download via the multicast updates, stations download using a standard TCP update.
2.If multicast updates are disabled, updating of all stations is performed only in general mode—via the TCP protocol.
To setup multicast updates, use the following parameters:
•UDP datagram size (bytes)—size of UDP datagrams in bytes.
Allowed range is 512–8192. To avoid fragmentation, it is recommended to set a value less than MTU (Maximum Transmission Unit) of the network.
•File transmission time (ms.)—during specified time, single update file is transmitted, after that Dr.Web Server starts sending the next file.
All files which failed to transmit at the step of multicast protocol update, will be transmitted at standard update process over the TCP protocol.
•Multicast updates duration (ms.)—duration of update process via multicast protocol.
All files that failed to transmit during update stage via multicast protocol will be transmitted in process of standard update via TCP protocol.
•Packages transmission interval (ms.)—interval of packages transmission to a multicast group.
The low interval value may cause significant losses during package transfer and network overload. It is not recommended to change this parameter.
•Interval between retransmission requests (ms.)—with this interval Agents send requests for retransmission of lost packages.
Dr.Web Server accumulates these requests after that sends lost blocks.
•“Silence” interval on the line (ms.)—when a file transmission is over before allowed time has expired, if during specified “silence” interval no requests from Agents for retransmission of lost packages are received, Dr.Web Server considers that all Agent received updates files and starts sending the next file.
•Retransmission requests accumulation interval (ms.)—during specified interval, Dr.Web Server accumulates requests from Agents for retransmission of lost packages.
Agent request lost packages. Dr.Web Server accumulates these requests during specified time slot after that sends lost blocks.
To specify the list of multicast groups from which multicast updates is available, setup the following parameters in the Multicast groups section:
•Multicast group—IP address of multicast group in which stations receive multicast updates.
•Port—port number of Dr.Web Server network interface, to which transport multicast protocol is bound for updates transmission.
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For multicast updates, you must specify any unused port, particularly, different from the port that is specified in the settings of transport protocol for the Dr.Web Server operating. |
•Time to live—Time to live of a datagram for data transfer during multicast updates.
•Interface—IP address of Dr.Web Server network interface, to which transport multicast protocol is bound for updates transmission.
Every line contains setup of one multicast group. To add one more multicast group, click 
.
When you configure several multicast groups, please note the following features:
•For different Dr.Web Servers, which will distribute multicast updates, must be different multicast groups specified.
•For different Dr.Web Servers, which will distribute multicast updates, must be different Interface and Port parameters specified.
•For using several multicast groups, sets of stations which are included into these groups must not overlap. Thus, each station of anti-virus network can be included only into one multicast group.
In the Access control list section, you can configure restrictions for network addresses of stations to which multicast updates can be sent:
•Stations that are allowed to receive multicast updates, listen specified multicast groups and receive updates using the standard scheme (see procedure 1).
•Stations that are denied to receive multicast updates, do not listen specified multicast groups for updates but download all updates via TCP (see procedure 2).
Configuration of the lists is the same as the configuration of the lists in the Security section.