Networking broadcasts and excessive traffic

[lengoo]

Dear All,
I was speaking with another consultant with regards to his and my network.
I am currently using the network address 10.0.1.x with a subnet of 255.255.255.0 and he is using the network address 192.168.1.x, subnet 255.255.255.0
He is saying that mine is a class A range and his is a class C range which I agree but what I'm not 100% sure of is that he is saying that because of this, my network is probably a lot more busy due to all the broadcasting.
My subnetting is the same as that of a class C so in my mind, the amount of broadcasting traffic should be the same. Is there any truth as to what he is saying??
Thanks

 

[PalmTest]

Hi Lengoo

I agree with you.
You both have a /24 subnet which gives you 254 possible hosts.
There is no reason why a 10.0.1.x network would 'initiate' more broadcasting traffic than a 192.168.1.x, at least I do not know it.
It merely depends on the number of active hosts and the kind of applications and/or protocols you have running over your network.
If you also use AppleTalk/NetBIOS/IPX/DecNet instead of TCP/IP only one will expect more broadcast traffic.

... just my thought ...

 

[KiscoKid]

Agree with Palmtest. The actual class of your LAN subnet is not the cause of additional broadcast overhead traffic when compared to a Class C subnet. As Palmtest says this is usually due to 'chatty' LAN protocols that perhaps have been configured on servers or PC's and the type of applications that have been deployed. These are the kind of broadcast-generating sources you can eliminate.

You can't easily eliminate some broadcast types, e.g. ARP or DHCP without some kind of network topology overhaul but you can reduce them if the LAN is well-designed.

May be worth downloading a sniffer like Ethereal (

http://www.ethereal.com/download.html)

and trying to analyze what the bulk contributors are to all your broadcasts.

Hope this helps

 

[jneiberger]

Network classes are irrelevant in modern networks. It would help if you completely did away with classful thinking. Think classlessly, both of you have /24 subnets. All that means is that you could potentially have the same number of hosts, but that still has no bearing on the amount of broadcast traffic you'll see in production. That depends on how many real hosts you have, what OS they're running, and what applications they're running.

John

 

[PalmTest]

Hi Lengoo,

Do you think you have more broadcast traffic on your LAN than 'neccesary' ?
Does it bother you, or your users ?

In addition to KiscoKid, another free sniffer is packetyzer.
(

http://www.packetyzer.com)

This tool uses the engines from Ethereal but has a Windows GUI (which some admins prefer above the Motif look :-D ).
These tools allow you to hunt down the printers which still have AppleTalk/IPX enabled (Jetadmin boxes) or a server with NWLink active.

 

[lengoo]

brilliant! thanks

 

[BuckWeet]

Yea..

tell that guy to go read his IP Networks for dummies book again...