Archived from groups: comp.dcom.lans.ethernet (
More info?)
Hi there thanks for the help Walter.
Actually I made a typo.
It should have been:
"Question is, will the performace/speed of users in floor B be slow in
accessing the servers on switch A?"
Should have been 'A' not 'B'. Sorry.
Yes, same VLAN, same subnet, no router between the 2 floors.
From your post so I presume that's bad news for me?
The single uplink will be shared among the users?
Our applications are a file server and oracle database(blobs) which
consists of lots of .pdf scanned files that users consistently access.
So I presumed it was going to be a problem for a 100-base uplink to the
lower floor.
I think I'll start investing into giga-lan (1000) then.
One of our cisco switches has an optical module for gig-lan. Could look
into that too.
Any other suggestions? Thanks
On 8 Jan 2005 06:11:34 GMT, roberson@ibd.nrc-cnrc.gc.ca (Walter
Roberson) wrote:
>In article <1klut0hrunqam5or7cojcbsh1ci9tfhtfs@4ax.com>,
>AcCeSsDeNiEd <dillon@SpamMinuSaccessdenied.darktech.org> wrote:
>:Hi have a switch called A on level/floor A.
>:Some of it's ports are directly connected to some of our servers and end-users.
>
>:Now, we are also branching out to the floor below us.
>:I figured to cut costs/time we will uplink a single port from switch A to another Swtich called 'B'
>:located in floor B.
>
>:Question is, will the performace/speed of users in floor B be slow in accessing the servers on
>:switch B? Will it result in users B having to share the bandwidth of the single uplink? (e.g
>:100mbits/100 users)?
>
>Will everything be in the same VLAN? Will everything be in the same
>IP subnet? If the answer to both is Yes, then the users on switch B
>will not need to any of the bandwidth of the uplink when they
>are connecting to servers that are also on switch B. Similarily,
>the users on switch A will not need to use any of the bandwidth of
>the uplink when they are connecting to servers that are also on
>switch A.
>
>If you have users on switch B who are connecting to systems on
>switch A, or users on switch A who are connecting to servers on
>switch B, or if different subnets or VLANs are involved and there is only
>one router (attached to either one of the switches), then all the
>active connections will share the single link. Whether that is a problem
>or not will depend upon how much traffic is going over the link.
>
>
>There are a couple oi issues of varying importance to keep in mind:
>
>- If your users are all using the same nameserver, then the DNS traffic
>will have to cross the uplink for one of the two groups. Once the
>IP of the destination system has been determined, user traffic will
>only have to cross the uplink to get to the appropriate server
>if the server is on the other floor from the user.
>
>- If you are using NETBIOS, then you should be aware that NETBIOS
>uses broadcasts, and those broadcasts are going to cross the uplink.
>Broadcasts are an important part of NETBIOS resource locking, so you
>can't just filter the broadcasts without unwanted effects. [Well,
>without -more- unwanted effects, considering it is NETBIOS we're
>talking about.]
>
>- Internet traffic is going to end up crossing the uplink for
>one of the two floors, depending where your WAN router is.
>
>- If your filesystem backup device is on the other floor than
>the device being backed up, then the backup traffic will cross
>the uplink. Backups can often be automatically scheduled
>for hours when users won't be working, and so would not interfere
>with user traffic, but if you have any kind of decent backup
>device, your backup speeds are going to be limited by the
>speed of the network. If you have large filesystems, then you
>might find [as we do] that -user- traffic may rarely need
>more than the equivilent of 10 Mb/s, but that server-to-server
>traffic, or especially backups will use the full available
>bandwidth of the uplink for long periods (generating lots of
>alarms on whatever program you are using to monitor the
>health of your network...)
To e-mail, remove the obvious