Re: probably an easy routing question, so please help

On May 16, 10:18 am, Trendkill <jpma...@xxxxxxxxx> wrote:
On May 16, 9:57 am, pk <philip.kl...@xxxxxxxxx> wrote:



On May 15, 2:55 pm, Trendkill <jpma...@xxxxxxxxx> wrote:

On May 15, 3:33 pm, pk <philip.kl...@xxxxxxxxx> wrote:

I'm not routing master, so this might be obvious, but I've been
curious about the answer to this question. Say an individual was
issued two IP blocks from their ISP.

IP Block 1 : 123.123.123.0 /28
IP Block 2 : 123.123.123.128 /28

If the individual doesn't really care to separate the two networks for
any reason and was just unfortunately issued two /28 blocks instead of
one /27 block, isn't the link between the two networks going to suffer
unnecessarily? For instance, if Server A located in Block 1 is
plugged into the same gigabit switch as Server B in Block 2 and they
want to initiate a file transfer, they are required to run out to the
default gateway (ISPs router) through a T1 (perhaps) connection and
back in when it would have been much faster for them to go directly to
the other's gigabit ethernet port on the switch? If this is the case,
would this be remedied, albeit poorly, by just subnetting both of
these ranges together into one giant class C address range? (I
understand fully that they wouldn't be able to access the rightful
owners of the rest of the IP addresses in that range as they would
search on their local LAN for them and time out, but this is a
hypothetical situation and only serves to educate myself on the
concept.) That said, how SHOULD this be handled in order to keep the
connection between the subnets optimal?

I'm quite sure that I'm missing some key concepts here, so please be
kind and explain them to me.

Thanks.

pk

Provided both of those networks are off the same edge router, and
routing is enabled, the traffic will not have to go across the WAN/
Internet link, and will instead route to the directly connected
network. This should work without issue.

OK, that makes sense, but if the uplink is coming out of the switch
from a 10Mb link to the router and the computers are both hooked into
gigabit ports then it is a big difference right? There's no way for
that switch to be a bit smarter (without turning into a router) and
not run out the 10Mb port to the router with all of its traffic,
correct? Whereas before they would have transferred at gigabit rate,
they now will be 100 times slower?

Technically yes you are correct. Unless you have a L3 switch or a
router with gig ports, you will potentially have limits for any
bandwidth going inter VLAN. I've been trying to think through your
option of running a /24 behind the scenes and simply not addressing
nodes in the two networks you don't own. I'm not really sure if this
would work or not, as it your router technically would have to
advertise the /24, unless of course you could use distribution lists
or something to split it up as necessary. I think your best bet is to
sit down and really analyze your servers/nodes and come up with a
design that keeps your high traffic boxes on one switch/subnet or the
other. I doubt you have 126 boxes that are the same application, etc,
and probably could be split into some kind of logical groups by high
traffic. Thus ensuring that intra VLAN traffic is maximized, and
inter-vlan traffic is minimized. If you do have a server (database or
such) that is central to both networks, perhaps its better to just
dual home it to each network. All depends on your requirements......

Well, the issue is that there is one computer that will need to access
every other computer at a very high rate, our backup server. I've
spent the last 45 minutes wading through the poorly organized Cisco
website just trying to find the most inexpensive non end-of-sale/end-
of-life Layer 3 switch with 2 gigabit (non-fiber) uplink ports and
probably 24 10/100 ports. You're correct in presuming that all of the
network devices don't need gigabit connections (iLOs and such) so I
have no problem placing them on 10/100 ports on a new Layer 3 switch.
What's the deal with end-of-sale/end-of-life products? Are they to be
avoided? Can you guys offer me any suggestions as to hardware devices
I should be looking at? I'm lost...the product catalog is so
extensive.

.

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