all 5
of these "edge" switches connect to another switch of
the same model with a 100Mbit multi-mode (1300
nanometer) fiber uplink which connects to a Cisco
Catalyst 5500 for our routing needs.
hmmm....... "connects to a Cisco Catalyst 5500 for our routing needs."
How is the 5500 doing routing? Do you have vlans and a RSM (or MSFC)
installed?
Is there a real router here somewhere that is actually taking packets from
one network and putting them on another? Are all the router interfaces 100
mbit?
DHCP is out of your control? I'm afraid it sounds like you have bigger
problems (layer 8). If whoever is doing this migration can't the DHCP I
can't imagine how the project can succeed.
You're giving us info little by little but still not enough to see your
network.
If you see good performance on a local subnet and degraded performance
crossing subnets then whatever is between them is a bottleneck. Normally a
Cat5500 shouldn't be that bottleneck especially if it's doing the routing
(with a RSM/MSFC).
Can you elaborate on how traffic is getting from one subnet to another?
Kevin Wigle
----- Original Message -----
From: "jeongwoo park" <[EMAIL PROTECTED]>
To: "Groupstudy" <[EMAIL PROTECTED]>
Sent: Wednesday, 08 November, 2000 17:13
Subject: Why not supernetting?
> Hi All,
>
> I am looking for advice on a LAN performance issue. i
> am running primarily NT4 and win2K boxes on a 100Mbit
> UTP Ethernet LAN.
>
> my servers are on static IPs on one subnet while my
> clients pick up DHCP addresses (assigned out of my
> control) in any one of half a dozen other subnets.
> file transfer and printing performance between client
> and server is averaging 1Mbit/sec when computers are
> in different subnets. switch the same two computers to
> static IPs in the same subnet and throughput jumps to
> a respectable 30-70Mbit/sec. i need to keep the
> clients on DHCP as i don't have enough static IPs to
> go around for the subnet the servers are in.
>
> all clients and servers are attached to one of 5
> Allied Telesyn 8126XL 24-port managed switches. all 5
> of these "edge" switches connect to another switch of
> the same model with a 100Mbit multi-mode (1300
> nanometer) fiber uplink which connects to a Cisco
> Catalyst 5500 for our routing needs.
>
> When the clients are on different subnets the file
> transfers appear to take a long trip through the
> router with a huge performance penalty (1Mbit/sec).
> when the client and server are on the same subnet the
> packets do NOT appear to be routed (perhaps they are
> handled using ARP?) and the performance is very good.
> ping response times on both switches and routers is
> under 20ms. This is where I believe supernetting could
> be a solution to this slowness, because I think
> supernetting allows me to put all stations in the same
> subnet, witch avoids routing needs.
>
> I got some responses to my previous post from people
> saying that supernetting would slow down the speed
> because there would be too many stations in big
> broadcast domain, which contradicts what I am willing
> to do.
>
> Am i missing some key concepts here that might improve
> my understanding of this tragic performance?
>
>
> any help would be greatly appreciated.
>
> take care,
>
> jw
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