Slow Network File Copies 1

[AdmanOK]

I have an ATM network between a site in Tulsa, OK and Houston, TX running between two Cisco 3662 routers. The circuit is 4Mb/s with a guaranteed availability of the whole channel. If I copy a file using a protocol like FTP or something I can get the full 4Mb/s speed, however if I try to copy a file from a Windows server using SMB then I only get around 2 - 3Mb/s... does any one know how to improve this performance? The ping times between the sites are around 45ms. The only networking protocol running at either site is TCP/IP and the two sites are directly connected; there are no hops in between other than the ATM cloud.

 

[gconnect]

yes, SMB sucks by nature. what is happening is that

1) your pc's are constantly negogiating with other PC's and Servers
2) the data transmissions are not optimized BY ANY MEANS. if you take a pkt capture you will notice ALL THE MINUTE pkts (16, 130, bytes ,etc) for READS, READ/WRITES, and connecting to the file system TREECONNECTandX. When you use FTP or HTTP to download the files you will be using 1460 bytes of data per pkt for data tranfers and less pkts instead of 13 bytes that will take ALL DAY LONG.

if you have ethereal (pkt sniffer), there is an option to see SMB performance and server responce time. Take a capture and go to Tools > Statistics > SMB Responce Time

I have this same problem at my job. We have an Interbase database that also depends on SMB for access and network printing. i configured Modular Quality of Service to make it a little better. i re-write all the SMB (tcp 139) and Interbase (tcp 3050) pkts with a IP Precedence of critical so that that traffic is routed first.

i made some documentation on my website on how to configure this. i rewrote it as a dummy company. scoll down to the section that reads "Cisco Quality of Service / Policy Routing". You need Adobe Reader (it's pdfs)

http://www.getconnected-it.com/infoarch.html

enjoy,
-gC-

 

[AdmanOK]

gconnect: Thanks for the reply... I kinda figured that was the case... but I wanted someone to confirm it for me. I'll check out the suggestions that you made in your documentation! I'm not sure that it's going to help in my case though because it's not like there's other traffic eating up the link... when I do an SMB copy it uses about 2MB and the other 2MB is sitting there idle... I just hate paying for something that I can't use!

 

[gconnect]

We have a 45Mbps capable WAN and SMB transfers were still horrible. MRTG (and 'show interface' commands) never showed anything out of the ordinary, but the SMB traffic was still very slow. it was taking 4+ minutes to print a page across the WAN (as no servers were located in that bldg). Although all other traffic (Web, FTP, Telnet - TermEmulation to AS400) was fine from the same bldg. Windows SMB is slow but also, don't get me started about the scaled down SMB implementation of Quantum Snap Servers............yuk!

as far as the routers........
i tried priority queuing at first but it was killing router processors and made the problem worse. it doesn't work with route-caching therefore every pkt had to be process switched (per ACL lookup).
Then i switched over to modular QoS. The great thing about it is that it works with route-caching/fast switching. Therefore it doesn't put a load on your routers and it does it's job.

hope it works out for you
-gC-

p.s. also

http://www.cisco.com/en/US/products...configuration_guide_book09186a00800b75e4.html