Cisco Systems Internet slowness

Bookmark this page:  YahooMyWeb Yahoo!  Google Google  Windows Live Favorites Windows Live  del.icio.us del.icio.us  digg digg  Add to Netscape Netscape
Subject Author Date
Internet slowness Someone 12-19-05
Posted by Someone on December 19, 2005, 12:49 am
Please log in for more thread options
We have about 40 Switches in our network which span 9 buildings with
T1 connection between the buildings. Our Internet connections is very
very very slow. An analysis done by a consulting company suggested
that we add spanning-tree root value o all our core switches. Would
this improve our internet experince, or are ther other things the we
can do to improve or Internet performance. Thanks.

Posted by nazgulero on December 19, 2005, 5:42 am
Please log in for more thread options
Hello,

looking at the amount of buildings and switches you are mentioning, I
asume you have several hundred users ? I would have a look at the load
on the T1. Depending on the IOS version you are running on the router
connecting to the Internet, you could either turn on ip accounting on
the interface where the T1 is connecting to (with the =B4ip accounting=B4
interface command), and then look at the output with the =B4show ip
accounting=B4 command, this will show you the source and destination IP
address pairs, as well as the amount of packets sent. Possibly, your
users are running streaming audio or video over the T!, which would
quickly saturate the link.
You could also try and turn on NBAR protocol discovery, with the
interface command =B4ip nbar protocol-discovery=B4, and then look at the
output with the =B4show ip nbar protocol-discovery=B4 command.=20

HTH,

Naz


Posted by on December 20, 2005, 4:49 am
Please log in for more thread options
> We have about 40 Switches in our network which span 9 buildings with
> T1 connection between the buildings. Our Internet connections is very
> very very slow. An analysis done by a consulting company suggested
> that we add spanning-tree root value o all our core switches

As you seem to have concluded you need expert help
on site.

It is not clear if you have got it in this case or not.

Setting the STP 'root value' or more correctly Bridge Priority
may or may not change the topology. If it does change the
topology it may or may not be better for any particular traffic.

A half decent model is that to get between any two points
on the network traffic goes via the root. It is best if the root
is at the centre since if the root is at an edge some traffic
may have to traverse twice the diameter of the network
to get between two points. If the root is at the centre
then the max "distance" between two points is
only the network diameter.

Note that traffic does not necessarily go all the way to the root.
That is though the worst case.


Similar ThreadsPosted
Internet slowness December 19, 2005, 12:49 am
PIX TCP slowness when routing & doing NAT June 22, 2005, 4:17 am
Routing Question - How to send default internet traffic to PIX and VPN traffic from router out internet February 27, 2007, 1:58 pm
How does the internet really look like ? October 5, 2005, 5:47 pm
Pix-to-Pix & Internet May 22, 2006, 11:43 am
dmz with internet access September 4, 2005, 10:24 am
Access Internet through VPN October 7, 2005, 3:15 am
Slow Internet on T1 December 17, 2005, 2:31 am
VPN Internet Issues January 8, 2006, 8:56 am
VPN Internet Issues January 8, 2006, 8:55 am
VPN Internet Issues January 8, 2006, 8:57 am
PIX 515 to PIX 515 via Internet & IPSec, should I get a VAC? February 21, 2006, 12:27 pm
NAT/PAT + Internet connection April 17, 2006, 5:22 am
internet ip to local ip with pix June 6, 2006, 9:43 am
PIX 515 - Cant get to Internet, but VPN works? July 24, 2006, 2:09 pm