Advanced Multicasting
NewsRoom 45 uses Port
5510
for the multicast port, and the address is
230.250.250.250
. This is where the refresh messages are sent from in NewsRoom 45. By default, this is normally turned off on a "smart router", and needs to be turned on. Some routers refer to it as IGMP (Internet Group Multicast Protocol).
Does your router support this ? If so, it can be set to this address, and will only be active for NewsRoom 45 clients. This document outlines the bandwidth, size, and packet volume of this protocol that carries dynamic updates within the NewsRoom 45 program.
Does your router support this ? If so, it can be set to this address, and will only be active for NewsRoom 45 clients. This document outlines the bandwidth, size, and packet volume of this protocol that carries dynamic updates within the NewsRoom 45 program.
Definition:
IGMP:
The protocol that governs the management of multicast groups in a TCP/IP network. To sign up for a multicast group, a Host Membership Report is sent by a user's machine to its nearest routers, which forward that data to routers outside the local network. The routers are kept current by polling the users' machines with Host Membership Query messages."
The NewsRoom 45 server will send out refresh packets when a user on the system adds to any of the databases (Wires, Audio, Contacts, Casts, Item stores). Also if the Wire/Audio Captures file to the system. If the system is idle, the only message is from the wires, as they purge old stories once a day at a specific preset time .. usually early in the morning ... 2 a.m. approx.
Below is a quick outline of the use of IGMP IP packets in the NewsRoom 4.5 system, from the programmer that wrote the software.
WHERE THEY ORIGINATE:
In the NewsRoom 45 software suite, only the services running on the server, and the audio capture programs generate IGMP packets. This includes the KLZ Wire Store service, the KLZ Cast Server service, and the main Netfileshare service. The current audio capture program generates its own IGMP content change packets.
In general, a message is generated any time any news content (text/audio) is: added, deleted, or updated. The IGMP packets are less then 512 bytes in size. The actual packet size will depend on the type of content, and how it was altered.
By default, NewsRoom uses the IGMP group address of
230.250.250.250
and a group port of
5510
. For support reasons we like to keep every site on the same group address, if possible. Should the default NewsRoom group address conflict with another system, we can change it.
PACKET VOLUME:
When the NewsRoom system is idle (no users/services changing content), no IGMP packets are generated. The volume of IGMP packets will increase as the system alters content.
As an example: if a user edited an item in the item store, the system would send out one IGMP packet to indicate that the item is being edited, and another when they post their changes, or cancel the edit operation of the item.
When a news story is posted to the KLZ Wire Store service, one IGMP message will be created for every wire queue the item is posted to.
When an audio clip is filed to the NewsRoom server, one IGMP packet will be sent at the start of the audio transfer, and one when the audio transfer to the server is completed.
Any content stored on a local computer running the NewsRoom 45 client software will
NOT
generate any IGMP packets when it is created, or altered.
EFFECT ON BANDWIDTH:
NewsRoom only generates an IGMP packet when content is changed. All changes to news content require a varying amount of bandwidth, depending on the size of the altered content item.
If you post an audio clip, the two IGMP change packets generated consume a small percentage of the bandwidth compared to transferring the audio.
When a short news story is transferred to the wire store service, the IGMP messages could consume the same bandwidth as the small text story filed.
NewsRoom 45 actually sends fewer IGMP packets than NewsRoom 4 sent Mail Slot messages. So if the broadcast bandwidth used by the mail slots in version NewsRoom 4 was not a problem, the IGMP packets in version NewsRoom 45 will not use any more bandwidth.
WHY IGMP:
The NewsRoom 45 software suite uses IGMP as a notification system to provide content change information. In NewsRoom 4 this was done using Windows Mail Slot messages, another form of broadcast packets.
A Mail Slot message can only be received by one application on a system at a time, and requires all computers to be members of the same network domain. With IGMP packets, many applications on the same computer can receive the same IGMP packets at the same time, and there is no Windows domain issues.
A mail slot message is sent as a broadcast packet, and is routed to all computers on the same subnet. In contrast, a multicast packet will only be routed to computers that have registered to be a member of a specific multi-cast group."