From: fwells12 (fwells12@xxxxxxxxxxx)
Date: Tue Feb 13 2001 - 18:38:47 GMT-3
I appreciate your feedback Fred. Solid advice. One thing I did not quite
grasp was your statement 'I would space my subnets acccordingly for all
routers' would you be kind enough to elaborate on what you meant by it
please.
----- Original Message -----
From: Fred Ingham <fningham@worldnet.att.net>
To: frank wells <fwells12@hotmail.com>; <ccielab@groupstudy.com>
Sent: Tuesday, February 13, 2001 11:13 AM
Subject: Re: IP addressing thoughts...
> Frank: The basic idea is sound but before you assign a given range to a
> router I suggest you read the instructions for any fixed addresses. If
> there is a required loopback of 172.16.225.0/30 on r2, for instance,
> your scheme falls apart.
>
> I suggest ranges of 32 rather than 16 (will work for 8 routers) and also
> space out the networks to the lowest mask requested. For instance if
> there is a required network of /22 somewhere in the network I would
> space my subnets acccordingly for all routers. This guarantees no
> overlaps.
>
> There are no points in the lab for saving address space. You should
> complete your addressing before configuring the routers and also draw a
> network diagram. Going into the lab with a fixed addressing scheme can
> cost you time. Rather, you should be able to construct addressing
> quickly after reading the requirements. On rebooting - in the lab I
> recommend you do this often - there are no points for not rebooting and
> it can
> clear up nagging problems.
>
> My opinion, Fred.
>
> frank wells wrote:
> >
> > I am giving a little thought to how I am going to handle the IP
addressing
> > in the lab. Regardless of the IP address/mask I am given I want to come
up
> > with a scheme which allows me easy summarization of all routers and
their
> > connected OSPF network segments.
> >
> > I am almost certain Cisco will throw the VLSM-FLSm issues at me and I
want
> > to be prepared.
> >
> > Lets say we get the following address/mask given to use: 172.16.0.0 and
we
> > are able to cut it up any way we want.
> >
> > Give me your thoughts on the following idea:
> >
> > 172.16.0.0 use mask 255.255.240.0 to get 14 useable subnets (not
including
> > subnet zero) I chose the 24 bit subnet mask to anticipate being given
> > possible RIP/IGRP FLSM addresses to
> > deal with. I assign a contiguous range of subnets to each router like
so:
> >
> > R1=172.16.16.0 - 172.16.31.0
> > R2=172.16.32.0 - 172.16.47.0
> > R3=172.16.48.0 - 172.16.64.0
> > R4=172.16.64.0 - 172.16.71.0
> > R5=172.16.72.0 - 172.16.87.0
> > R6=172.16.88.0 - 172.16.95.0
> > R7=172.16.96.0 - 172.16.111.0
> > R8=172.16.112.0 - 172.16.127.0
> >
> > Now when asked to do something like intra-area summarization to the max,
I
> > can easily summarize each routers connected networks with a simple
command
> > like area 1 range 172.16.16.0 255.255.240.0 right?
> >
> > Also, by planning this way I would like to be able to address my network
> > before I begin typing it into the routers. This would give me an
advantage
> > as I would be able to assign the highest IP addresses in the respective
> > subnets to a/the loopback addresses etc. Ultimately I want to not have
to
> > reboot the routers because I created an OSPF adjacency prior to adding
the
> > loopbacks etc.
> >
> > I am also thinking about drawing a line on top of my picture and
deviding it
> > into as many segemnts as I have routers like so:
> >
> > R1 R2 R3 R4 R5 R6 R7 R8
> > |-------|-------|-------|-------|-------|-------|-------|-------|
> > 16 32 48 64 72 88 96 112 127
> >
> > By doing this I can easily mark off along my line which subnets I have
> > already used too which may prove to be useful. Plus, it takes up little
to
> > no room on your paper.
> >
> > Hope the ASCII pic isn't mangled too bad...
> >
> > Good idea/bad idea?, thoughts please.
> >
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