Re: Switch Questions
- From: adykes@xxxxxxxxx (Al Dykes)
- Date: 22 Aug 2005 14:08:05 -0400
In article <decujq$rvu$1@xxxxxxxxxxxxxxxxxxxxxxx>,
Walter Roberson <roberson@xxxxxxxxxxxxxxxxxx> wrote:
>In article <1124726552.628160.58700@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>,
> <bpanders71@xxxxxxxxxxx> wrote:
>:I manage a small network (75 desktops, 4 servers) with a single HP
>:Procurve 4000m switch which has one 1-port gigabit module and the other
>:7 modules having ten 10/100 ports. I've got two HP Proliant DL servers
>:with dual gigabit NICS. Obvioulsy, with only one gigabit port, I can
>:only hook one of the NICS on one of the servers to it. What I'm
>:thinking of doing is purchasing a separate smaller Linksys 16 port
>:gigabit switch (under $400) so I can team the dual NICS on both of the
>:proliant servers to get 2GB on each. FWIW, the two servers are a
>:terminal server which hosts about 15-20 users (currently dual NIC'd at
>:200 Mbps), and our main database/file/print server (only one NIC at
>:1GBps) which sees some pretty heavy use. Both are win2k.
>
>I'd think it likely that that plan is headed for trouble.
>
>
>:My questions, therefore, are:
>
>:1) I'm guessing I can plug the Linksys into the Procurve through the
>:gigabit port, correct? Should I be using a CAT 6 cable for this or
>:will CAT 5e do?
>
>Cat5e will do, at least for moderate distances.
>
>
>:2) Since the Linksys is a managed switch
>
>Could you check that again? Last time I checked about 3 months ago,
>the least expensive *managed* gigabit switch I could find was about $1000.
>The $400 Linksys switches were NOT managed at the time.
>
>:I could configure Port
>:trunking. Is this something that should always be done when setting up
>:dual NICS (primary goal is load balancing with lesser emphasis on fault
>:tolerance)?
>
>Port trunking? As in putting in multiple 802.1Q VLANs? That's not going
>to help fault tolerance: if your fault tolerance is MAC based then
>the MAC in the other VLAN would not be visible; if your fault tolerance
>is IP based then the two ports would have to be in different subnets
>in order to be able to select the proper port during normal operations.
>
>
>: I tried port trunking when configuring dual 100 NICS on
>:the terminal server, but saw no readily apparent benefit.
>
>Do you perhaps mean port aggregation?
>
>Port aggregation depends on the algorithm being used to distribute
>the packets between the available links. I don't recall which algorithms
>the Procurves have available. Often the algorithms are based upon
>taking the last N bits (2^N >= number of aggregated ports) of the source
>or destination and using that as the link index; sometimes the source
>and destination bits are xor'd. Unless you have configured per-packet
>load balancing on your aggregation ports (I -seem- to recall seeing
>that the Procurve could do that), the result is that any one
>source + destination MAC pair will always use the same link. Aggregating
>N ports does not get you N times the bandwidth (unless per-packet):
>instead it gives you opportunities to parallelize up to N different
>streams. Like a multilane highway: your car can't drive at 180 miles
>per hour just because there are three lanes, but 3 cars can independantly
>drive at 60 miles per hour on the three lanes.
>
>
>:3) Will this scenario actually give me noticeable improvements? I
>:don't want to invest even a little bit of money if improvements are
>:minimal.
>
>If you are expecting heavy traffic over the gigabit ports, then
>chances are that you will be disappointed with the $400 Linksys.
>On the consumer gigabit devices, the aggregate throughput supported
>is usually fairly low. Many of the consumer gigabit devices use the
>same chipset, so you pretty much have to take a jump in price class
>in order to get serious simultaneous bandwidth. Something like a
>Cisco Cat2960 perhaps; I imagine others will pitch in with other
>reliable high-throughput devices. [Note: there have been some reports
>of bad experiences with Netgear's line of managed gigabit switches,
>which look nice on paper...]
>--
> Look out, there are llamas!
have you done some measurements and determined traffic to each of your
servers? Do you know that any of your servers are
bandwidth-bottlenecked?
--
a d y k e s @ p a n i x . c o m
Don't blame me. I voted for Gore.
.
- References:
- Switch Questions
- From: bpanders71
- Re: Switch Questions
- From: Walter Roberson
- Switch Questions
- Prev by Date: Re: Switch Questions
- Next by Date: Re: Switch Questions
- Previous by thread: Re: Switch Questions
- Next by thread: Re: Switch Questions
- Index(es):
Relevant Pages
|
