Summary: Enabling multicast on Linux and windows.
OverviewMulticast is the delivery of information to a group of destinations simultaneously, using the most efficient strategy to deliver messages over each link of the network only once, and create copies only when the links to the destinations split. The word "multicast" is typically used to refer to IP Multicast, the implementation of the multicast concept on the IP routing level, where routers create optimal spanning tree distribution paths for datagrams sent to a multicast destination address in realtime. However, there are also other implementations of the multicast distribution strategy listed below. GigaSpaces uses multicast in the following cases:
To enable the important capabilities above, you should enable multicast on machines running clients, spaces or services.
Configuring Multicast on LinuxIn some cases, Linux distributions do not have multicast enabled by default and the /etc/hosts file does not include the IP address associated with the server's hostname. An error that is frequently met is: hostname associated with the localhost in /etc/hosts. The machine's hostname in /etc/hosts should be associated with the IP address set to the server's network interface, or to the external static NAT IP address of the server (the address clients should connect to). 127.0.0.1 localhost 192.168.10.127 Mylinux
Before running GigaSpaces, make sure your network interface supports multicast, and the appropriate routes are properly configured. To check if your network interface supports multicast, run the following ifconfig: $ /sbin/ifconfig -a eth0 Link encap:Ethernet HWaddr 00:30:48:2E:67:BA inet addr:192.168.10.127 Bcast:192.168.10.255 Mask:255.255.255.0 inet6 addr: fe80::230:48ff:fe2e:67ba/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:89049707 errors:34 dropped:0 overruns:0 frame:34 TX packets:79402911 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:24029278032 (22.3 GiB) TX bytes:52438225932 (48.8 GiB) Base address:0x3000 Memory:dc300000-dc320000 eth1 Link encap:Ethernet HWaddr 00:30:48:2E:67:BB inet addr:192.168.0.1 Bcast:192.168.0.255 Mask:255.255.255.0 inet6 addr: fe80::230:48ff:fe2e:67bb/64 Scope:Link UP BROADCAST MULTICAST MTU:1500 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:0 (0.0 b) TX bytes:0 (0.0 b) Base address:0x3040 Memory:dc320000-dc340000 lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:16436 Metric:1 RX packets:1366770822 errors:0 dropped:0 overruns:0 frame:0 TX packets:1366770822 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:319301580062 (297.3 GiB) TX bytes:319301580062 (297.3 GiB) sit0 Link encap:IPv6-in-IPv4 NOARP MTU:1480 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:0 (0.0 b) TX bytes:0 (0.0 b) If the MULTICAST attribute in the fourth line of the eth0 properties is not present, it's possible that your kernel has not been compiled with multicast support. Before re-compiling the kernel, try enabling multicast on your network interface (eth0 in this case) via ifconfig: $ /sbin/ifconfig etho multicast To check that multicast routing is configured, run the following route command: $ /sbin/route -n Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface 192.168.0.0 0.0.0.0 255.255.255.0 U 0 0 0 eth1 192.168.10.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0 169.254.0.0 0.0.0.0 255.255.0.0 U 0 0 0 eth1 224.0.0.0 0.0.0.0 240.0.0.0 U 0 0 0 eth0 0.0.0.0 192.168.10.1 0.0.0.0 UG 0 0 0 eth0 If the destination 224.0.0.0 entry is not present, you need to enable multicast routing. To enable multicast routing, run the following route command as root: $ /sbin/route -n add -net 224.0.0.0 netmask 240.0.0.0 dev eth0
Alternatively, try executing the command above as part of a startup script in /etc/rc.d/*.
Configuring Multicast on WindowsTo enable multicasting from a token ring on a Windows® 2000 workstation to any Windows 98/NT machine, set the TrFunctionalMcastAddress parameter to 0 in the Windows 2000 registry:
Configuring Multicast Scope Time-To-Live (TTL) ValueThe multicast Time-To-Live (TTL) value specifies the number of routers (hops) that multicast traffic is permitted to pass through before expiring on the network. For each router (hop), the original specified TTL is decremented by one (1). When its TTL reaches a value of zero (0), each multicast datagram expires and is no longer forwarded through the network to other subnets. Packet Sniffer/Network Analyzer ToolWireshark (formerly Ethereal) - accumulates years of network analyzing experience and is far more mature and known than other tools. It is a cross-platform packet sniffer/network analyzer tool (used both in Windows and Unix/Linux). It allows you to examine data from a live network, or from a capture file on disk. You can interactively browse the capture data, viewing summary and detail information for each packet. It has several powerful features, including a rich display filter language and the ability to view the reconstructed stream of a TCP session. ***Link required |
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