| Title: | FDDI - The Next Generation |
| Moderator: | NETCAD::STEFANI |
| Created: | Thu Apr 27 1989 |
| Last Modified: | Thu Jun 05 1997 |
| Last Successful Update: | Fri Jun 06 1997 |
| Number of topics: | 2259 |
| Total number of notes: | 8590 |
Hi, Can someone give me some guidance on this one? Customer situation is this...When using FDDI for dumping a file system on Ultrix, they see a thruput of 200kb/sec. This is somewhat acceptable, but if they use the standard MTU of 4096 (I believe) they see a problem in the Cisco Routers CPU times getting eaten up w/ the fragmentation issues of 4096 fragments from FDDI and 1500 byte segments on the ethernet side. They have a hack for changing MTU to 1500 at boot time in rc.local, but then the performance of the FDDI system is about 1/4 of the 200kb/sec I mentioned above... Any suggestions, Dan Lowry
| T.R | Title | User | Personal Name | Date | Lines |
|---|---|---|---|---|---|
| 1040.1 | KONING::KONING | Paul Koning, A-13683 | Wed Jul 28 1993 18:44 | 4 | |
You mean the Cisco router gets into trouble fragmenting a mere 200 kb/s? If so, throw it away; a product like that is clearly trash. paul | |||||
| 1040.2 | rdump seems to be the problem | CSC32::D_LOWRY | Thu Jul 29 1993 12:01 | 20 | |
Hi,
>You mean the Cisco router gets into trouble fragmenting a mere 200 kb/s?
>If so, throw it away; a product like that is clearly trash.
That is what I thought but here is some more interesting data
From the customer...
1. In discussing this problem with my telecom rep, he reminded me that this is
a problem with rdump, and not necessarily in the FDDI component. I ran a
test using rcp, ftp, and NFS; and was able to get throughput of 520-980
kilobytes per second across the FDDI. This is with the 1500 MTU.
Any ideas?
Thanks
Dan Lowry
| |||||
| 1040.3 | KONING::KONING | Paul Koning, A-13683 | Thu Jul 29 1993 13:38 | 3 | |
Huh? Fragmentation/reassembly is invisible to applications, such as rdump. paul | |||||