subnetmask and IP address

Hi All,
I have some qurries,Please answer
1.How exactly subnet mask will be used to identify the host by giving
the IP address?
2.suppose i have a subnet mask 255.255.248.0 and hosts
10.50.56.1 to 10.50.56.31
i)how exactly the network will resolve some packets addressed to
10.50.56.15 from outside
ii)if i want to send some packets to some ip, for example 171.17.89.10

from 10.50.56.15 what would be the source and destination address?
Thanking you
Prasi

prasi wrote:

> I have some qurries,Please answer

Homework?

prasi wrote:
> Hi All,
> I have some qurries,Please answer
> 1.How exactly subnet mask will be used to identify the host by giving
> the IP address?
> 2.suppose i have a subnet mask 255.255.248.0 and hosts
> 10.50.56.1 to 10.50.56.31


11111111.11111111.11111000.00000000 (255.255.248.0)
00001010.00110010.00111000.00000001 (10.50.56.1)
----------------------^ here is the net adress
-----------------------^----------^
between ^ ^ characters is the part of host address

11111111.11111111.11111000.00000000 (255.255.248.0)
00001010.00110010.00111000.00011001 (10.50.56.31)
----------------------^ here is the net adress
-----------------------^----------^
between ^ ^ characters is the part of host address


> i)how exactly the network will resolve some packets addressed to
> 10.50.56.15 from outside

if you have for ex. 192.168.0.0/24 and 10.50.56.0/21 then
if you sent packet form 192.168.0.1 to 10.50.56.15 there will be logical
equalizations done for dest adres, adres of the router and mask for
future routing decision.


> ii)if i want to send some packets to some ip, for example 171.17.89.10
>
> from 10.50.56.15 what would be the source and destination address?

this wont work, because the 10.0.0.0/8 net is local adress space, which
are not ruteable in the Internet. If the adres will be nated then src
address will be adress of your machine where the translation was done
and destination adres will be 171.17.89.10

> Thanking you
> Prasi
>

James Knott wrote:
> prasi wrote:
>
> > I have some qurries,Please answer
>
> Homework?
hi
NO not really
I just wanted to know i have got some confusion how exactly the bit
mask will be used (procedure) to find out IP
bye

prasi wrote:
> Hi All,
> I have some qurries,Please answer
> 1.How exactly subnet mask will be used to identify the host by giving
> the IP address?

The subnet mask identifies whether or not the host resides on the local
subnet. All bits in the IP that correspond to the 1 bits in the mask
identify the subnet.

> 2.suppose i have a subnet mask 255.255.248.0 and hosts
> 10.50.56.1 to 10.50.56.31
> i)how exactly the network will resolve some packets addressed to
> 10.50.56.15 from outside

This is the job of the router/gateway. The gateway has an IP on the
outside and will route packets to the local subnet.

> ii)if i want to send some packets to some ip, for example 171.17.89.10
>
> from 10.50.56.15 what would be the source and destination address?

The source is the from address (i.e. 10.50.56.15). However to travel
across the subnet, the mechanism is the MAC address. The source
determines if the destination is on the subnet by looking at the IP and
the subnet mask. If it's on the local subnet then the source gets the
MAC address of the destination using ARP. If the destination is not on
the subnet then the source sends the packet to a gatway that routes the
packet onto another network (i.e. the outside).

> Thanking you
> Prasi