I just recently was called out to a customer site who was complaining that
while they were using Norton Ghost sometimes they would get great throughput
and other times it would be dog slow. The workstation being ghosted was
plugged into a switch port at 100 full on a cat 5000 and the server was
plugged into the same switch at 100 full. The problem was they are using
secondary addresses so the traffic must bounce off the Cisco 3640 to and
from the server were the images are. The workstation would DHCP an address
on one of the other subnets. I had them set a static address on the same
subnet that the server was on and we would get 5 times the throughput. The
ghosting went from taking over an hour to about 5 minutes.
Since the addresses are already contiguous we are planning on changing the
subnet mask in an upcoming project so it's all the same address space.
Jim
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of
Diegmueller, Jason (I.T. Dept)
Sent: Thursday, July 06, 2000 1:06 PM
To: '[EMAIL PROTECTED]'; [EMAIL PROTECTED]
Subject: RE: Secondary IP address
: What are the advantages of using a secondary IP on and
: ethernet interface
Advantage? Other then the fact it can be used to "patch together"
two networks in a bind, none. It can be considered harmful for
performance. Imagine:
Router: 10.0.0.1/24, and 172.16.0.1/24 secondary
Host A: 10.0.0.2/24
Host B: 172.16.0.2/24
Both hosts and the router are going to a single hub. Host A needs
to communicate with Host B. By utilizing it's IP and subnet mask,
Host A determines Host B is NOT on it's local network and thus
sends the packet to it's default gateway (the router).
The router, having the secondary address, knows that the destination
network (172.16.0.0/24) is actually on the same interface it just
received the packet from. So it ends up ARPing for Host B and
reencapsulating the packet right back out the same interface it just
came in from.
All return communication by Host B must go along the same path (Router-->
Host A) even though they are technically on the same wire.
Obviously, you would never want to design a network like this from the
ground up, but it's sometimes necessary until you're able to readdress,
redesign, or whatever the case may call for.
___________________________________
UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html
FAQ, list archives, and subscription info: http://www.groupstudy.com
Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
___________________________________
UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html
FAQ, list archives, and subscription info: http://www.groupstudy.com
Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
