Multicast and localhost

Maybe not exactly a Java question, but it seems to apply to two disparate Java packages so people around here might know.
When, some time ago, I set up Eclipselink cache coordination I found that the default discovery method was to advertise the presence of an instance with a multi-cast to tell other instances where to connect. However the connection information that was sent in the multicast was "localhost", completely useless, of course. I actually had to override some methods to force the multicast to contain the actual domain name of the server doing the broadcast. There was no properties setting to change it.
Now I seem to be getting exactly the same thing trying to set up activeMQ. When each machine receives the broadcast from the other it tries to connect to itself, rather than the other machine.
On both the machines localhost resolves to the loopback address, not the actual IP of the machine in question.
What gives here? It seems more than a coincidence that two well-established packages appear to make the same fundamental error.
Of course I'm setting up activeMQ from the examples given in the web site, I'm not deeply into it yet, but the documentation never shows anything other than localhost as a host name.
Should localhost resolve to the machine's actual IP?

malcolmmc wrote:
EJP wrote:
Trying to connect to itself, or to the other broker?
Clearly it should be connecting to the other broker. It tries to connect to itself on a port that it's not listening on, and it doesn't connect to the other broker.
If it's trying to connect to itself on the loopback interface it all seems reasonable to me: why do you care?For one thing it keeps trying, producing copious log records but more importantly it doesn't connect to the other broker.
If it's trying to connect to the other broker and the other broker isn't on the localhost that could be a problem, but it's not what you've described so far.The other broker isn't on localhost, what would be the point?
Edited by: malcolmmc on 27-Jun-2011 18:32http://wiki.eclipse.org/EclipseLink/Examples/JPA/CacheCoordination seems to suggest you need to configure EclipseLink on each server with its own URL (with its external hostname) for access. Maybe if this is not specified, this setting will defauts to localhost?
It is old, but I think this thread may also be helpful: Cache Coordination RMI in Weblogic - problems

Similar Messages

What is the diffrence between multicasting and broadcasting?

hi friends
What is the diffrence between multicasting and broadcasting?
i'm bit confused in multicasting and broadcasting.

Broadcasts go everywhere within a range determined by the sender.
Broadcasting is deprecated and unliikely to go beyond the nearest router.
Multicasts go everywhere where receivers have declared they are present.
Multicast can be implemented beyond routers in a WAN which you control but ISP routers generally don't support it.

I have to send messages through UDP multicast and unicast from same port. In Labview I tried that it throws error. I heard it is possible by means of Datagram (UDP unicast and multicast) Port Sharing. How can it be achieved in Labview?

I have to send UDP multicast and Unicast messages to a remote port from a single source/local port. I tried by opening UDP unicast and multicast in the same port and got the expected error. I tried by opening a unicast connection and sending unicast messages.After that when multicast messages has to send I closed unicast and opened multicast in the same port.This is not throwing any error. But my requirenment is to comminicate with another application in C ++ which recieves this data, throwing an error of lost connectivity and both the applications are not abled to communicate properly.
In the other application with C++ this is implemented using port sharing. So how port sharing can be implemented in labview so that I can send both multicast and unicast messages from the same port?
Thanks in advance

UDP is a sessionless protocol, meaning that anyone listening on the specified port CAN receive the data. CAN because as you noted there is no guarantee in the protocol that it will be received. And if you send the data not to a specific address but a multicast address not only one computer can receive it but in fact every computer on the same subnet listening to that multicast address and depending on the TTL of the packet also computers in neighbouring subnets, although that last one is not a very reliable operation since routers can be configured to drop multicast packages anyhow despite of a different TTL saying otherwise.
Accordingly there is no real way to make sure that a receiving UDP port is not already in use, since you don't build up a connection. UDP is more or less analogous to shouting your messages through a megaphone, and anyone listening on the right frequency (port) can hear it. You do bind the sender socket to a specific port number but that makes little difference.
Rolf Kalbermatter
CIT Engineering Netherlands
a division of Test & Measurement Solutions

Multicast and wirerless

I have a 4404 controller running 6.0.202 code and more more people have Mac running bonjour and wanting to use Airplay. I see how to turn on Multicasting and even provide a Multicast address for IGMP snooping but does anyone have a good feel as to the overall load Multicast adds to the wireless network?
Thanks,
Gary

It depends on the type of deployment you have.
If the network infrastructure supports multicast, you should enable Multicast - Multicast as the controller multicast mode and choose a multicast address in the 239.X.X.X range.
If your network is not capable of supporting multicast, you would want to select Multicast - Unicast mode. This mode puts a load on the controller and on the wireless network as the Multicast is then sent as a unicast to each access point instead.
These support articles should help you.
Bonjour Deployment Guide
http://www.cisco.com/en/US/products/hw/wireless/ps4570/products_tech_note09186a0080bb1d7c.shtml
Multicast Deployment Guide
https://supportforums.cisco.com/docs/DOC-14713

ACL restriction of multicast and broadcast on SRW2016

Hello all,
I seem to be having difficulty setting up an ACL that restricts multicast and broadcast packets to a specified port on the SRW2016.
In brief, I have one (physical) port that I need to prevent any broadcast or multicast packets from being sent to. I need to allow clients which are on that port to send broadcast, however. My take on this was to create an ACL with one rule of the type:
Type: Deny
Protocol: Any
Source IP: 10.0.0.0/255.255.255.255
Destination IP: 224.0.0.0/0.255.255.255
Another type I tried was a 2-rule ACL to explicitly allow only a valid sender and deny all:
Type: Allow
Protocol: UDP
Dest Port: 1234
Source IP: 10.1.0.100/0.0.0.0
Dest IP: 10.1.0.101/0.0.0.0
Type: Deny
Protocol: All
I have tried various permutations these types of ACL (changing ordering, etc) but everything I have tried so far has allowed the multicast packets through unless I block it at the sending port (which obviously blocks it from all ports).
Any suggestions or comments would be appreciated. Is what I'm trying to do even possible in the SRW2016?
Thanks,
Mike

Just to make sure I was creating/applying the ACLs correctly, I did a simple test with a very basic rule: I just set type to deny (basically a deny all rule). I applied this rule to one port of the switch and verified that it was working by attempting to access the switch's web configuration interface (which correctly was inaccessable). However, the multicast packets were still being delivered (verified via both an Ethernet dump and visual inspection of the switch's LED).
Based on the above information, I feel it's fairly safe to say that Multicast is not filtered correctly via ACLs on the SRW2016. Apparently Multicast packets take a different logical path than "normal" packets. Since I don't expect an immediate firmware patch, I suspect that I need to see if I can get a router in addition or as a replacement for the switch.
Edit: I found a method that appears to restrict the multicast packets via the "Bridge Multicast" interface (basically created a rule for the MAC related to my multicast address, set to Forbidden on one port, but this is not a generic solution for all multicast and I don't seem to be able to have more than 1 MAC address in the list...), but broadcast still gets through, regardless of the ACL I set up for the port.
I'm beginning to wonder if my understanding of ACLs is flawed - does anyone know if they're applied to incoming packets for a port, outgoing packets for a port or both? My assumption was both, but if the rule were only applied to incoming packets, it would explain the behavior I'm observing.
Message Edited by michael.beresford on 03-02-2009 02:46 PM

Display dashboards simultaneously from company's server and localhost

Hi Experts,
We have a laptop that we have installed SAP B1 (Server and Client) locally. This laptop can connect to two servers;
localhost and to company's server. We would like to ask whether there is a way to display dashboards
from company's server using Sap Client when laptop is connected to company's network. Also if it is possible to
display dashboards simultaneously from company's server and localhost.
Thank you in advance,
Vassilis Korolis

Hello,
Well, as far as I know it is not possible to make it automatically using SAP Business One Client, but we have made a wrapper for standard client that might help.
The idea behind is to create two (or even more, if required) connections in Skybuffer SBO LogonPad and then to click the connection that you would like to start (either local server or remote server that is accessible at company network).
Additionally, it is possible to open two SAP Business One Client instances that are connected to two different servers from one machine simultaneously with help of Skybuffer SBO LogonPad, but I have never tested how stable the connects are, so please be careful with this. But in case of read only access (like you've mentioned - dashboards display), I can say that it is safe enough.
Here is the picture that shows that I can access two different servers from one machine:
And you can download Skybuffer SBO LogonPad from here:
Skybuffer SBO LogonPad (version 0.2)
P.S. that's a freeware wrapper to facilitate different license servers connectivity for SAPB1 consultants.
Kind Regards,
Siarhei

Weechat Highlight Monitor Script for IRC and Localhost (Bitlbee)

Hey guys.. I've been struggling with this one for some time now, thought I might as well get some feedback
So bacically, I have the weechat plugin 'highmon.pl' and I have the Channel, Nick, and Message (when highlited) output to conky on my desktop.
Now the part I cant figure out is how can I get the same scripts that do that to also output the highlights i get from my bitlbee session (which is open in a separate terminal window connected to localhost)
As long as I am in my home dir, I can get this to work for each individually, but as I like to use tmux, weechat in one tab, weechat --dir ~/.weechat/bitlbee in another so I can watch my facebook chat and irc chat without having to log in and out of servers. But because my Bitlbee session is started in ~/.weechat/bitlbee my scripts no longer work...
further to this, I've tried to modify them to work just in ~/.weechat/bitlbee but havent succeeded there either...
ok, the scripts
highmon_channel.sh
echo -e $(cat ~/.weechat/logs/perl.highmon.weechatlog | awk 'END{split($2,a,"#"); print a[2]}')
highmon_msg.sh
echo -e $(cat ~/.weechat/logs/perl.highmon.weechatlog | awk 'END{print $4, $5, $6, $7, $8, $9, $10, $11, $12, $13, $14, $15, $16, $17, $18}')...
highmon_nick.sh
echo -e $(cat ~/.weechat/logs/perl.highmon.weechatlog | awk 'END{print $3}' | cut -f1 -d'>' | cut -f2 -d'<' | cut -f3 -d '!' )
these scripts get called by conky to output my highlighted message on the desktop..
If anyone knows how I can ammend these scripts to also work with a weechat instance started in the directory of ~/.weechat/bitlbee that wold rock my world
[i tried changing the directories in these scripts to ~/.weechat/bitlbee/logs/perl.highmon.weechatlog ... that didn't really work tho]
If anyone can tell me its possible to connect to both freenode and localhost in the same weechat session id also be impressed!
you know how there is always just one more thing you'ld like to do to your desktop... that one last thing that if you achieved it, it would make you relax and feel complete? this is that for me
any help is much appreciated..
(for the record, I didn't write these scripts, I came across them throughout my life)
Last edited by CoolWhip (2011-11-03 01:20:04)

Of the second and third scripts, the latter could perhaps be deemed the "most secure"; however, it might block more than you want. If you really want to use one of those, then I'd suggest using the second script. Otherwise, I'd recommend that you take a look here. (I only slightly examined the first script.... I do not understand the language of the comments, and I'm no iptables whiz. )
Also, note that you don't have to use an actual script to set up the rules; rather, you can save the rules you want to a file that will be read by iptables automatically (/etc/iptables/iptables.rules). Here's a modified version of mine:
# /etc/iptables/iptables.rules
# These rules (and the commented instructions) derived from:
# http://ubuntuforums.org/showthread.php?t=159661
*nat
:PREROUTING ACCEPT [163:50538]
:POSTROUTING ACCEPT [40:2451]
:OUTPUT ACCEPT [40:2451]
COMMIT
*filter
:INPUT ACCEPT [0:0]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [0:0]
:FIREWALL - [0:0]
:TRUSTED - [0:0]
-A INPUT -j FIREWALL
-A FORWARD -j DROP
-A FIREWALL -m state --state RELATED,ESTABLISHED -j ACCEPT
-A FIREWALL -i lo -j ACCEPT
-A FIREWALL -j TRUSTED
-A FIREWALL -j DROP
# put your own exceptions here, like so (replacing <tcp/udp> with either "tcp" or
# "udp" -- minus the quotes -- and <port number> with the port you'd like to open):
# -A TRUSTED -p <tcp/udp> -m <tcp/udp> --dport <port number> -j ACCEPT
COMMIT
Of course, there are benefits to keeping the rules in a script. For instance, you could then easily set the default iptables rules, allow all traffic, etc. Plus, some firewall-related things (such as the various echo commands in the scripts you provided) cannot (to my knowledge) be done by iptables alone.
If you already have a script that sets up the rules you would like to use, you can save yourself the hassle of creating a rules file by following the directions outlined here.
Last edited by ssjlegendx (2008-08-06 20:17:00)

[svn:osmf:] 16975: Fix bug FM-964, add media factory item for RTMFP multicast and remove the item from OSMFPlayer

Revision: 16975
Revision: 16975
Author:   [email protected]
Date:     2010-07-19 15:20:00 -0700 (Mon, 19 Jul 2010)
Log Message:
Fix bug FM-964, add media factory item for RTMFP multicast and remove the item from OSMFPlayer
Ticket Links:
    http://bugs.adobe.com/jira/browse/FM-964
Modified Paths:
    osmf/trunk/apps/samples/framework/OSMFPlayer/src/OSMFPlayer.as
    osmf/trunk/framework/OSMF/org/osmf/media/DefaultMediaFactory.as

Welcome guy -
Unless you are using Spry menus as a learning experience, you should move forward to a menus system that will display properly on the millions of portable devices that won't work with Spry which was deprecated 2 years ago.
Many are using JQuery menus or pure HTML/CSS menus.
If you wish to continue your Spry for learning experience, we'll be glad to assist; please let us know.
By the way, your submenus are not showing because you need to add the red value to this rule in your vertical CSS
ul.MenuBarVertical ul.MenuBarSubmenuVisible{
    width: 220px;
    left: 180px;

'unable to connect' and 'localhost' and index.php and dreamweaverCC

Hi.
I am developing a Web Site and index.php is my point of entry.
Document Root Library/WebServer/Documents
so my path is: Library/WebServer/Documents/dwwdSite
httpd.conf file is modified to add index.php and have it listed first.
<IfModule dir_module>
DirectoryIndex index.php index.html
<IfModule>
Troubleshooting:
I was using Netbeans IDE and when I ran index.php it opened in the browser.
When I launched 'any' of my index.php files from Netbeans IDE, they opened correctly in the brower
I am now using DreamweaverCC and when I run the index.php Error Message ' Unable to Connect'.
For the last 2 days I have been working on this and I am completely stuck.
This morning I thought of another way to test the 'unable to connect' error.
I decided to copy this same file into Netbeans IDE and I NOW get the same Error Message ' Unable to Connect'
when running index.php from Netbeans.
Somehow, my settings are not correctly configured anymore.
Here are my screenshots from Dreamweaver > manage sites.
I believe that this is a rather simple fix that I am somehow not seeing.
Maybe some can spot some mistake.
I appreciate your help and explanation.

Site window settings.
Site Name: dwwdSite
Local site folder: /Library/WebServer/Documents/dwwdSite
Server window settings.
Server Name: testing Server
Address: Macintosh HD/Library/WebServer/Documents/dwwdSite
Connect using: Local/network
Testing: yes (checked)
Server folder: /Library/WebServer/Documents/dwwdSite
(I also tried this: Server folder: /Library/WebServer/Documents)
Web URL: http://www.localhost/dwwdSite
Server Advanced tab: (within server window settings)
Testing server: PHP MySQL
Advanced Settings window.
Local info: Web URL: http://www.localhost/dwwdSite
Enable cache: yes (checked)

Verity spider and localhost

Verity Spider is licensed to only spider a local server.
Because of this, it indexes my collection with
http://localhost/ instead of
http://www.mydomain.com/
My problem is that none of my users outside the network can
access search results because all of the search result URLs look
something like:
http://localhost/index.cfm?go=main.default
when they should look like
http://www.mydomain.com/index.cfm?go=main.default
This is the command I am using to run vspider.exe:
vspider.exe -collection
d:\cfusionmx\verity\collections\mycollection -start
http://localhost/ -indinclude * -cgiok
If I use my actual domain as a start, i.e. -start
http://www.mydomain.com/, I
get "Connection refused" (presumably because Verity Spider is only
licensed for local spidering)
Is there a vspider param that will let me declare localhost =
http://www.mydomain.com as far
as the indexed records are concerned?
Also if I am limited to spidering localhost, how can I use
the -indexclude and -exclude options if I wanted to limit something
like
http://sub.mydomain.com (using
anything other than localhost in exclusions also gives me a
"Connection refused")?
Any insight is appreciated, thanks for your time

Roger,
I looked over the code and it looks fine. I think the problem
might be that you are a complete retard.

P2P multicast and upstream bandwidth

Hi,
I'm in the process of developing a realtime video chat application where multiple users can send video streams simultanuously. The number of users receiving the streams can be very big, e.g. 10 broadcasters and 500 receivers, each receiver should get all streams.
I use RTMFP connections to an FMS and streams are published in P2P multicast groups by passing the groupspec to the NetStream constructor. Currently I'm having problems with audio/video synchronization and video stream 'jumps' (not continuous). From what I read on other threads, this is related to the fact that there is not enough upstream bandwidth for sending the streams. So my questions are:
How to calculate the required upstream bandwidth on every peer for the given example of 10 broadcasters and 500 receivers (is it 10*bandwidth of one stream)?
What settings (on NetStream, Camera, Microphone etc.) should be used for best results and how to adapt them based on the number of broadcasters?
I hope my questions make sense!
Thanks,
Haykel

I have done some tests to find out how much upstream bandwidth is used for different situations. The data is taken from the 'multicastInfo' property of all involved 'NetStream' objects as follows:
Multicast Data: average of 'multicastInfo.sendDataBytesPerSecond' of all streams.
Multicast Control : average of 'multicastInfo.sendControlBytesPerSecond' of all streams.
Different measurements have been done for different situations:
The user is broadcasting and not broadcasting
Varying number of connected users
Varying number of users broadcasting
I have limited the maximum video bandwidth to 16 KBytes with 'Camera.setQuality(1024 * 16, 0)'.
The application uses only application level multicast (passing a groupspec to the NetStream constructor). In this test all peers are on the same LAN and the FMS server is on a remote machine.
The results in Bytes/s (click to enlarge):
What I have noticed is that the outgoing multicast data volume grows by ~15 KByte with every new connected user (receiver) and goes down when the number of broadcasters grows. Is that normal? Does it mean that only the broadcasters are sharing the streams with the other peers? I thought that every peer would share the data with a number of neighbours (i.e. 3) which would share with their neighbours and so on.
During the tests I have also checked for a/v delays and noticed the following:
For every new stream, at the beginning audio and video are in sync but have a delay of ~3 seconds
After ~20 seconds the video delay becomes marginal but the audio remains delayed and so goes out of sync with video
After ~30 seconds the audio delay becomes marginal and goes in sync with video (a/v are now stable)
The delays of 20 and 30 seconds grow up to more than a minute when the number of broadcasters grows
My questions:
Are my measurements correct?
Why is the outgoing multicast data volume growing with every new receiver? Is the publishing stream sending the data to all peers?
Should I expect the bandwidth to grow indefinitly with the number of receivers or will it stabilize at some value?
How to decrease the time required for a/v to become stable (in-sync with a small delay)?
Is P2P multicast a good choice for this kind of applications (up to 10 broadcasters and a very big number of receivers)?
Any advices???
Thanks.

The application level multicast and VoD/LiveTV application

Hi,
As I read from the document, so far only user's video published out from a Flash Player 10.1 could take advantage of the new application level multicast. But can other video applications scenarios, such as VoD and Live TV (encoded by Flash Live Media Encoder) , also take advantage of this new feature? Please advise. Thanks.

Thanks for the answer, but does Adobe has any plan to enable it and when?

Multicast and WebcamSubscriber issues for 10.1

Hi,
I'm trying to subclass WebcamSubscriber in 10.1 lib to create a custom video subscriber.
When multicast is on, a subclass of WebcamSubscriber for flash 10.1 does not always act as expected. Specially, after playing a stream, it does not seem to send a "NetStream.Play.Start" event.
Since the 10.1 lccs library is not open source (why?), the best I could do was by subclassing and overriding, here is a simple test to reconstruct the problem:
public class TestSub extends WebcamSubscriber {
     public function TestSub() { super(); }
     override protected function onNetStatus(e:NetStatusEvent):void {
          trace(">> onNetStatus: " + e.info.code);
          super.onNetStatus(e);
Given the above code, a full cycle events of a subscriber in a p2p state (multicast = true) is like this:
>> onNetStatus: NetGroup.Neighbor.Connect
>> onNetStatus: NetGroup.MulticastStream.PublishNotify
>> onNetStatus: NetStream.MulticastStream.Reset
>> onNetStatus: NetGroup.MulticastStream.UnpublishNotify
>> onNetStatus: NetGroup.Neighbor.Disconnect
The above shows a publisher playing an stream, waiting for some time and then closing the connection.
The question is: why is that the 10.1 version never sends a "NetStream.Play.Start" event in the p2p state?
The problem could be traced to WebcamSubscriber#playStream(), but the source code for 10.1 is not available. Also when I tried overriding playStream() using the code in 10.0 lib, I got a peer timeout message. Is the code for WebcamSubscriber#playStream() in 10.0 the same as 10.1?

Raff. wrote:
Can you try to run your application linked to the 10.1 LCCS lib on a machine that only has FlashPlayer 10.0 installed ?
Can an application which is linked to lccs for player 10.1, run on a 10.0 player?
This sounds like a problem in lccs. Could you check the difference in code in WebcamSubscriber#playStream() between 10.0 and 10.1? (I cannot do this as 10.1 is not open source.) Whatever the problem is, it's initiated from that method.

Distribution Point Multicast and Unicast at same time

Hi,
Scenario: SCCM 2012 R2. All in one server.
The server is distribution point (PXE and Multicast enabled).
The questions are:
If any Multicast dependency fails (i.e firewall blocks ports for multicast traffic),
Does the OS image will be deployed using unicast?
Is mandatory the multicast deployment method?
Thanks!

Hi,
No, when the multicast fail the TS would failed.
If you select the checkbox “Transfer this package only via multicast” in Configuration Manager Client Package Properties, which is mandatory.
We
are trying to better understand customer views on social support experience, so your participation in this
interview project would be greatly appreciated if you have time.
Thanks for helping make community forums a great place.

Broadcast, multicast and bandwidth

multi-casting and broad-casting consume the same amount of
bandwidth, right?
switches know the (ip ----> MAC) mappings.
however, in the run-time, multi-cast groups are entered and exited.
so only java knows what datagrams to drop.
so, switches/routers must propogate all
datagrams to all targeted sub-nets and
then to ALL mac addresses.
logically there are plenty of reasons to use multicast groups.
bandwidth-wise, there are none.
rights?

Dead wrong.
Routers only propagate multicasts if they know there is a member of that group on the other side.
That's what the IGMP protocol is for.

Multicast and localhost

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