- Mobile computing:
- Internet host computer
can travel from
one geographical location
to another (arbitrarily far)
geographical location
- While the mobile host is
traveling:
- The existing TCP connections must not be interrupted !!!
- Internet host computer
can travel from
one geographical location
to another (arbitrarily far)
geographical location
- Mobile computing solutions are
available at
2 different levels:
different levels:
- (Data) Link layer
solutions
- This solution is similar to 802.11 wireless network with hand off
- Network (IP) layer solutions
- (Data) Link layer
solutions
- The Datalink Layer
mobility is
accomplished by using a:
- Mobile (cellular) telephone modem connection
I.e.:
- Connect a Cell phone modem to a laptop
- Example: AD3700 from Verizon
- Delivering messages to a
mobile host:
- A mobile host's
wireless modem has a
built-in
hardware address (K)
- The mobile host is
assigned a
IP address
(X) of the
infra-structure wireless network:
Each gateway of the wireless provider has an association table that maps:
Assigned IP address ---> Hardware address
- Packets from the
Internet are
transmitted to
the mobile host through the
wireless network
in a Layer 2 frame:
- A mobile host's
wireless modem has a
built-in
hardware address (K)
- Disadvantage:
- The operation requires
the Datalink Layer to
route the
message to
the destination
Therefore:
- There is one (large) physical network
- Mobile user
must remain on the
same physical network
- So the solution may be limited in geographical scope
- The operation requires
the Datalink Layer to
route the
message to
the destination