Symantec 5 manual Broadcast address in the /etc/llttab file, Link command in the /etc/llttab file

158Advanced VCS installation topics Using the UDP layer for LLT

■Make sure that the LLT private links are on different physical networks.

If the LLT private links are not on different physical networks, then make sure that the links are on separate subnets. Set the broadcast address in /etc/llttab explicitly depending on the subnet for each link.

See “Broadcast address in the /etc/llttab file” on page 158.

■Make sure that each NIC has an IP address that is configured before configuring LLT.

■Make sure the IP addresses in the /etc/llttab files are consistent with the IP addresses of the network interfaces.

■Make sure that each link has a unique not well-known UDP port. See “Selecting UDP ports” on page 160.

■Set the broadcast address correctly for direct-attached (non-routed) links. See “Sample configuration: direct-attached links” on page 161.

■For the links that cross an IP router, disable broadcast features and specify the IP address of each link manually in the /etc/llttab file.

See “Sample configuration: links crossing IP routers” on page 163.

Broadcast address in the /etc/llttab file

The broadcast address is set explicitly for each link in the following example.

■Display the content of the /etc/llttab file:

#cat /etc/llttab set-node Node0 set-cluster 1

link link1 udp - udp 50000 - 10.20.30.1 10.20.30.255

link link2 udp - udp 50001 - 10.20.31.1 10.20.31.255

■Verify the subnet mask using the ifconfig command to ensure that the two links are on separate subnets.

# ifconfig

eth2 Link encap:Ethernet HWaddr 00:04:23:AC:2B:E4

inet addr:10.20.30.1 Bcast:10.20.30.255 Mask:255.255.255.0 eth3 Link encap:Ethernet HWaddr 00:04:23:AC:2B:E5

inet addr:10.20.31.1 Bcast:10.20.31.255 Mask:255.255.255.0

The link command in the /etc/llttab file

Review the link command information in this section for the /etc/llttab file. See the following information for sample configurations: