A PM without a specified 'pool' size will have as many addresses in the
pool as there are ports configured with some combination of 'network dialin'.
The pool starts exactly at the ip address stated:
In your case it would be:
set assigned x.x.x.150 with a pool range from .150 to .197 (including .150),
46 addresses.
However, to satisfy the previous thread on IP pools (Sir Carpenter and
others) I have a recommendation to maximize the usable addresses in a network
range, say x.x.x.0 thru x.x.x.255, and the preservation of sanity in your
routing tables.
To fit the assigned IP address pools of five (5) PM3s with 48 addresses each
into one 256 address range, consider this:
(set pool to 48 even with PRI)
PM3-1 assigned address = x.x.x.16 pool = 48 routes = x.x.x.16/28,
x.x.x.32/27
PM3-2 assigned address = x.x.x.64 pool = 48 routes = x.x.x.64/27,
x.x.x.96/28
PM3-3 assigned address = x.x.x.112 pool = 48 routes = x.x.x.112/28,
x.x.x.128/27
PM3-4 assigned address = x.x.x.160 pool = 48 routes = x.x.x.160/27,
x.x.x.192/28
PM3-5 assigned address = x.x.x.208 pool = 48 routes = x.x.x.208/28,
x.x.x.224/27
One unused subnet is left over:
(maybe for your backbone, statically assigned users, or dialup routers?)
x.x.x.0/29 14 hosts = .1 - .14 broadcast = .15
By the use of 48 addresses in your pool, you will only have two routes
generated by OSPF - or statically set if your not up to OSPF - for each PM3.
NOTES:
If you use 48 addresses for your pool, though you are provisioned for PRI
with 46
usable ports, the loss of two addresses per PM3 (10 per network) is a
justifiable
loss for simplicity gained. Even though some may still disagree!
Because I like to avoid routing conflicts in general, I try never to use
the x.x.x.0 as a host address. Cisco and most UNIX routed/gated have an
attachment to subnet zero.
The last note concerns the x.x.x.255 address. In an otherwise peaceful
network, this address can safely be used due to the fact that the network
is fully subnetted INCLUDING the first subnet:
[[ x.x.x.0/29 14 hosts = .1 - .14 broadcast = .15 ]]
Furthermore, if you decide to use the range of addresses [hosts = .1 - .14]
with masks of 255.255.255.0, including the PMs, there may be an exposure to
the user assigned the x.x.x.255 address.
*** this I have not had the opportunity to check/test.
Happy pooling,
-- Tom Fellenz Technical Support Staff Engineer Lucent Technologies, Inc Data Networking Systems Group Remote Access Business Unit 4464 Willow Road, Pleasanton, CA 94588 tlf@livingston.com (800)458-9966 (1) http://www.livingston.com
At 06:21 PM 12/30/97 -0500, Stephen B. Henry wrote: > >I have a PM3 populated with 48 modems fed by two megalink T1s giving me >46 lines. I have set the pool 'Assigned IP_Address' to .150 (showing my full >Class C, of course!) which should use numbers from .150 to .195 only it >seems to use numbers upto .196. > >Is this an error? Does it start at 'Assigned IP_Address' +1 or does it >infact use numbers upto .197 (48 for the actual number of modems?) > >Whatever the answer to above, is it possible to limit it to the 46 IPs it >needs? > >Regards, > >Steve > >Stephen B. Henry >Director of Operations >headwaters network >A division of WebNET Corporation > >"If a man speaks in a forest, and no woman hears him, > is he still wrong?" > > > >- >To unsubscribe, email 'majordomo@livingston.com' with >'unsubscribe portmaster-users' in the body of the message. > > - To unsubscribe, email 'majordomo@livingston.com' with 'unsubscribe portmaster-users' in the body of the message.