Wireshark-users: Re: [Wireshark-users] [Bulk] [Wireshark-announce] What is a good average for mal
From: "Martin Katz" <[email protected]>
Date: Tue, 10 Jun 2008 14:26:48 -0700

That depends on your NIC speeds and the load on each subnet (between switches). It is natural to get malformed packets when two NICs try to transmit at the same time. At the “throughput limits” discussed below, you will usually get about 10% malformed packets (at half the throughput, you get about half the malformed packets, etc.).

 

10baseT has a 75-80% throughput limit (8 Mb/s). A subnet running with a higher load gets a lot of malformed packets. If you have any device on a subnet that requires 10baseT, the whole subnet runs as 10baseT. Using switches instead of hubs should limit this effect and filter out malformed packets. On the other hand, that means that you cannot easily see the malformed packets.

 

Higher speed NICs should have a throughput limit closer to 90%.

 

This is why companies spend the extra money to use switches instead of hubs where they can.  If you have a lot of hubs, as you expand the network (or replace equipment), add more switches. They still have problems, but fewer. When you do add switches, make sure your servers are on switches, not hubs and try to keep each connection to the switch under 50% throughput (limits malformed packets to under 10%).

 

If you are well under the throughput limit and have more than 10% malformed packets, you can assume that you have a bad piece of equipment.

 

I hope this helps

Martin Katz

 


From: [email protected] [mailto:[email protected]] On Behalf Of Wireshark announcements
Sent: Monday, June 09, 2008 7:19 AM
To: [email protected]
Subject: [Bulk] [Wireshark-announce] What is a good average for malformed packets

 

Hello,

 

I’m in the process of analyzing traffic from our network and I’m coming across some malformed packets.  Before I start going capture crazy.   What is a good (average) of malformed packets on a network?

 

-Albert -