| Why does the TruCluster product require a separate
subnet for the MC, memory channel, network?
There are several answers to this question
The cluster memory channel is a separate and
distinct physical network on which only cluster
members reside. If you attempt to use/share another
network subnet address with the TruCLuster MC subnet
you will run into the following problems:
1. The current RIP protocol does not support routing of
broadcasts across a subnet which spans multiple physical
networks. This will break any networked application which
utilizes broadcasts.
2. Since at least two cluster members must be acting as
gateways to provide application availability there would be
multiple gateways interconnecting two physical networks
within the same subnet. This condition is not supported
by the current proxy ARP protocol.
3. The traffic on the MC physical network needs to
be tightly controlled to prevent saturation
from outside sources.
4. The traffic on the MC physical network needs to
be contained such that the cluster does not
saturate an outside subnet with its internal
subnet traffic.
5. Subnet based security with ifaccess.conf is used to
prevent an outside node from spoofing or impersonating
a cluster member.
What subnet address can I use for my cluster?
The best answer to this question is to use your local
network configuration and administrative methods and
allocate a subnet according to your current model of
subnet allocation. If you have no such method or if
subnet addresses are a scarce commodity you must be a
bit more creative.
NOTE: IP addresses must be managed carefully to prevent
colisions of the address space.
It is important that you choose a subnet address which
is not already in use. The Internet Assigned Numbers Authority
(IANA) has reserved, in RFC 1918, the following three blocks
of the IP address space for private internets:
10.0.0.0 - 10.255.255.255 (10/8 prefix)
172.16.0.0 - 172.31.255.255 (172.16/12 prefix)
192.168.0.0 - 192.168.255.255 (192.168/16 prefix)
It is also important to choose addresses and netmasks that are
suitably subnetted to match any already existing subnets or
networks in your distributed environment. In general this means
to be sure to use a compatible broadcast mask with respect
to the other subnets in your network.
Use commands like "nslookup" to check if an IP address is
already in use.
NOTE: RFC 1918: http://andrew2.andrew.cmu.edu/rfc/rfc1918.html
[Posted by WWW Notes gateway]
|
|
> It is important that you choose a subnet address which
> is not already in use. The Internet Assigned Numbers Authority
> (IANA) has reserved, in RFC 1918, the following three blocks
> of the IP address space for private internets:
>
> 10.0.0.0 - 10.255.255.255 (10/8 prefix)
> 172.16.0.0 - 172.31.255.255 (172.16/12 prefix)
> 192.168.0.0 - 192.168.255.255 (192.168/16 prefix)
Thank you! Now I understand why we can do this!
- Sean
|